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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 549-563 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Visualization of stainable material in the neural lobe of the rat provided the most reliable index of the age at which secretory activity can first be recognized, though preceded by both hypothalamic synthesis and axonal transportation. A problem of interpretation was encountered in the neural lobes of fetal and infant animals, due to different staining responses obtained during this age period, to the two methods of staining employed; chrome alum hematoxylin-phloxin and aldehyde fuchsin after oxidation by either acidified potassium permanganate or performic acid. With aldehyde fuchsin the material of the neural lobe is stainable selectively from the eighteenth day of fetal life to adulthood. With hematoxylin phloxine the first staining response also occurred in the posterior lobe but much later, at the end of the first postnatal week.The staining situation in the pars neuralis has its counterpart in the differentiating hypothalamic nuclei; complicated by the differentiation of the supraoptic nuclei some days in advance of the paraventricular nuclei. After aldehyde fuchsin staining, evidences of neurosecretory activity were present in the perikarya of the supraoptic nuclei at birth, but mature neurons were rarely seen in the paraventricularis until at least 24 hours later. Nuclei of fetal hypothalami were not studied, but the demonstration of stainable material in the fetal neural lobes constitutes circumstantial evidence of functional competence of some neurons of either one or both types of nucleus, most likely the supraoptic.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 1-5 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Small crenulated erythrocytes appear in the circulation of Rana pipiens during metamorphosis, increases in number as metamorphosis proceeds and gradually lose their wrinkled appearance. At the end of metamorphosis the entire red cell population has been replaced by these new cells. Thyroxine induces the premature appearance of these new cells in young tadpoles.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 39-50 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The distribution and morphology of the argentaffin cell population within the stomach of the albino rat has been investigated histologically. The argentaffin cell's situation is restricted to and evenly distributed over the antrum, lying usually in the basal third of the mucosa among mucous cells. A band of mucosa, less than a millimeter wide, containing argentaffin cells, extends from the antrum and encircles the stomach just caudal to the forestomach. The argentaffin cell population is found in less than three-tenths of the total stomach by weight, a point for consideration in serotonin assay.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 89-100 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This report presents a study of cataracts seen in a random-bred strain of Swiss mice with Balb/c mice used as a control group. The embryonic development, and histological and slit lamp observations of the lenses in the two groups of animals are contrasted.The cataract is dominant in its inheritance (Tissot, '62). It appears either unilaterally or bilaterally as a dense white opacity in the lens substance. The earliest sign of abnormal formation occurs at 14 days of embryonic development. This is associated with a defect in the primary lens fibers formation. Progressive degeneration of these fibers occurs until they are reduced to a mass of cellular debris seen at the last day of gestation. The secondary fibers are also laid down in an abnormal manner. The normal lamellar arrangement of the secondary fibers is not seen in cataractous lenses.The abnormal lens fiber development leads to progressive vacuolization.The mature cataract seen in the adult is filled with many vacuoles, the largest ones occurring at the equatorial region. The nuclear region consists of a clumpy eosinophilic mass with scattered calcified areas. The rate of growth of the secondary fibers is different from that of the normal group. Most of the mature cataracts in the adult contain a vascularized epithelium.There are three possible areas of primary involvement which may lead to the development of the cataract. This are: (1) A defect in the development of the primary lens fibers; (2) A defect in the development of the secondary lens fibers; (3) An abnormal lens epithelium which may interfere with nutrition of the lens and thus initiate cataract formation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Spiroid orientation of the circumferential heart wall muscles is described for Centruroides sculpturatus Ewing. This muscle arrangement accounts for differences in ostial position when the heart of this species is compared to that of Uroctonus mordax Thorell. Other differences, such as number of lateral arteries present, cannot be explained on the basis of circumferential muscle orientation.The histology of the heart and associated vessels, but not the supraneural vessel, was found to be similar in both species. The lateral, posterior, communicating and sternal arteries all possess a muscularis composed of irregularly spaced, apparently branched, striated muscle fibers. External to this is a covering of connective tissue. The lumina of these arteries, the aorta, and the supraneural vessel are lined with a homogeneous, PAS-positive membrane. This membrane is also seen in blood vessels which penetrate the nervous system. It was not observed in vessels accompanying major nerves.Findings are compared to those of other authors. Differences in the structure of the hearts of these two species are discussed in relation to the microanatomy of other arachnid hearts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 233-240 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development and replacement of teeth in the frog Rana temporaria is analyzed by dividing the life cycle of the tooth into a number of stages. These stages are identified by the examination of alizarin whole mounts. The dentition in this species is fairly complete and the percentage of functional loci is approximately 74. The teeth in alternate loci are usually at about the same stage in development. The low percentage of non-functional loci is accounted for by the retention of functional teeth over a large fraction of the total life cycle time and the relatively rapid ankylosis of replacement teeth. It is suggested that tooth replacement is essentially a process which involves teeth in alternate loci and that the replacement waves (which connect alternate loci) run parallel to the longitudinal axis of the jaw and are of infinite length. This basic pattern is obscured by many breaks which occur in the replacement waves. The presence of such breaks may be accounted for by variations in the time intervals between the successive stimuli which initiate the Zahnreihen, or simply by the acceleration or deceleration of the development of teeth in one or more loci.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The major features of the morphogenesis of the muscles of the hindlimb, exclusive of the foot, are described and illustrated for the frog, Rana pipiens The description is carried through the stage XII larva, in which stage most of the muscles of the adult limb are present in essentially the definitive condition. As is true of other vertebrates which have been studied, the muscles of the hindlimb develop from two major premuscular masses. One of these lies along the dorsolateral margin of the limb and the other along the ventro-medial margin. Each of the two masses is subsequently divided into smaller and smaller subdivisions as the different muscle groups and the individual muscles are differentiated. In general, the more proximally located muscles differentiate before those which are located more distally and those of the dorso-lateral mass before those of the ventro-medial mass.The following muscles of the thigh, shank and tarsus develop from the dorsolateral mass: ileo-fibularis, glutaeus magnus, cruralis, ileo-femoralis, iliacus externus, iliacus internus, tensor fasciae latae, pectineus, adductor longus, peroneus, tibialis anticus brevis, tibialis anticus longus, extensor cruris brevis, tarsalis anticus, extensor digitorum communis longus and abductor brevis dorsalis. The following develop from the ventro-medial mass: compressor cloacae, circumflexor arteriae, pyriformis, semimembranosus, gemellus, gracilis major, gracilis minor, semitendinosus, adductor magnus, obturator internus, obturator externus, quadratus femoris, sartorius, plantaris longus, tibialis posticus, tarsalis posticus, plantaris profundus, intertarsalis and flexor digitorum brevis superficialis.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Tissues of White Leghorn embryos of stages 17-45 and chicks of one day, two days, and three weeks of age were frozen, sectioned in a cryostat and, where appropriate, were fixed in cold calcium formol. Acid phosphatase, non-specific esterase, adenosine triphosphatase, 5-nucleotidase, non-specific glycerophosphatase, nucleotidediphosphatase, and glucose-6-phosphatase were localized in these tissues. Ribonucleic acid, acid mucopolysaccharides, triglycerides, and neutral fats were localized in tissues fixed with FAA and embedded in paraffin.Positive acid phosphatase reactions were obtained in the epithelium of the trachea and esophagus at all stages of development. 5-nucleotidase was found in the muscularis mucosae of the esophagus at all stages. Non-specific esterase appeared with histodifferentiation of the esophageal epithelium. Ribonucleic acid was localized in the basal regions of the epithelium.Mucous glands of the esophagus are rich in ribonucleic acid and acid phosphatase at all stages of development. With histodifferentiation and the onset of secretion of sulfated acid mucopolysaccharides, the glands and their ducts become highly reactive for adenosine triphosphatase and nucleotide-diphosphatase, indicating a role of these enzymes in secretion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 277-281 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Testicular structure in bisexual teiid lizards (Cnemidophorus and Ameiva) is apparently unique among vertebrates in having a circumtesticular subtunic band of Leydig (interstitial) cells, that varies in species of Cnemidophorus from 1.2 to 42.1 cells in thickness (transverse cross-section), between the outer tunic (tunica albuginea) and the seminiferous tubules. The regression on body size, ontogenetic change, seasonal periodicity, and other aspects of structure and function of this subtunic Leydig cell structure are discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The egg chamber of Drosophila melanogaster consists of 16 interconnected cells surrounded by a monolayer of follicle cells. Each 16 cell cluster (from which the oocyte and 15 nurse cells differentiate) arises within the germarial region of an ovariole. To study the ultrastructure of the early stages in the formation and differentiation of egg chambers, a three dimensional reconstruction was made from serial thin sections through a germarium from a 24-hour old, virgin female. The germarium was found to be subdivided into three regions: (1) The mitotically active area where clusters of 16 cells originate from a series of cystocyte divisions, (2) the region where these cells interact with mesodermal cells, and (3) the region where the germarial cyst is transformed into the first egg chamber in the vitellarium. Since cystocytes were found to decrease in size with each division, the possibility exists that cell size may determine when the divisions cease. Models are presented which mimic with varying degrees of success the developmental changes the germarial cells undergo with time. Hypothesis are developed to explain why stem line oogonia are restricted to the anterior portion of the germarium, why mesodermal cells first interact with cystocytes in region 2, and why the oocyte is oriented posteriorly. The nuclear differentiations of the component cells of the chamber are described and correlated with observed differences in radiosensitivity. Symbionts were observed in the germaria of several strains of Drosophila, and the bearing of these findings upon nutritional studies is discussed.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The physiology and fine structure of the vibration receptor of the spider (Achaearanea tepidariorum) was studied throughout the process of molting. The physiological studies showed that there is no dramatic change in the receptor's vibration sensitivity as the time of ecdysis approaches. Only a gradual loss of sensitivity can be detected on a statistical basis using large numbers of spiders. The fine structural studies suggest that the connection between the sensory neurone and the receptor within the old cuticle remains intact up to the time that the cuticle is shed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Since the rabbit's eye more nearly resembles the human eye than any other mammal used in experimental investigations, a detailed study of its ciliary arteries has been made. A closely timed series of embryos injected through the living umbilical vein and rendered transparent show, in thick sections, silhouetted vessels in perspective. Heretofore the ciliary arteries have been studied from their first identification until they have reached the primitive choriocapillaris, but no farther. This study shows their complete history including their relation to the circulus arteriosus iridis major and to the pupillary membrane. Our special concern has been ferreting out the mode of migration of the components of the definitive arteries. New findings include: (1) an arteriovenous plexus which mediates the transference from vessels anastomotic with it to other such vessels; (2) functionally different segments of the primitive ciliary arteries; (3) different arterial and venous plexuses which play roles in embryonic development; (4) discovery of the realignment of the choriocapillaris into vertical vessel meshes with transverse anastomoses between them, each of which have different fates; (5) the mode of development of the circulus arteriosus iridis major; (6) a crown of venous vessels looping around the iris margin; and (7) a special arterial supply for the ciliary processes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The phylogenetic development of neuroglia (astrocytes, oligodendrocytes) was investigated in homologous cortical and subcortical forebrain regions of selected vertebrates. Microglia were not considered in the current study.Four to seven brains from each species were used. Scharenberg's modification for astroglia of del Rio Hortega's silver carbonate technique was used. The analysis of neuroglia cells was based on (1) the characteristic cellular morphology found in each species, (2) a comparison of the selected regions in each animal, (3) the interrelationships of astrocytes and their relations to neurons, blood vessels, and oligodendrocytes.The predominant type of neuroglia found in the fish, frog, and lizard was the ependymal cell; however, non-ependymal glial cells were also present. The bird represented a transitional phylogenetic stage from a predominance of ependymal glial to a predominance of non-ependymal glia. A progressive increase in the morphological relationships of glial cell bodies and processes to neurons was found with ascension of the phylogenetic scale from fish through primate.Interrelations were observed between adjacent astrocytic processes and cell bodies, and between astrocytes and oligodendrocytes. The processes of adjacent glial cells also appeared to show an increase in thickness at the point of approximation. A variety of astrocytes were observed ranging from small, round-oval shaped cells to large polygonal or stellate forms. Variations in the number of astrocytic processes, their thickness, and degree of secondary branching were described, and their possible functional significance was discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 1-8 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Gland cells of the gastrodermis of Hydra when isolated from the epidermis are capable of dedifferentiating into interstitial cells. Under proper environmental conditions these interstitial cells are capable of undergoing meiotic divisions and forming normal gametes. This dedifferentiation and redifferentiation sequence has been studied at the level of the light and electron microscope. It is concluded that in Hydra there is no specific germinal cell line determined during embryogeny, and that a somatic cell under proper environmental conditions can be induced to undergo meiosis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The rectal epithelium of Calliphora is made up of three quite distinct cell types: rectal, cortical and junctional cells.The thin wall of the rectal pouch is made up of rectal cells which are relatively simple and unspecialized; their general structure does not suggest any direct participation in ion transport.A function of ion and water transport can probably be ascribed to the cortical cells, which are arranged in the form of four cones which project into the rectal lumen. The cavity of each cone is filled up with tracheae, nerve and neurosecretory terminals, and connective tissue to form medulla. The medulla and cortex are separated from each other by deeply staining bridges or trabeculae to form an infundibular space. The most conspicuous feature of the cortex is the presence of an extensive intercellular sinus formed by complex infoldings of the lateral plasma-membranes. It is postulated that fluid, which is absorbed from the rectal lumen, is transported into the intercellular sinus and finally reaches the haemolymph via the infundibular space. The actual site of ion transport is probably the stacks of lateral plasma-membrane which are closely associated with mitochondria.The junctional cells, which are packed with microtubules, form a collar around the base of the papillae at the point of their insertion into the rectal wall.It is suggested that the neurosecretory terminals present in the medulla might release a hormone which controls rate of ion and water reabsorption by the papillae cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The long, filamentous antennal flagellum of Carausius morosus has on it three types of sense organs (1) tactile hairs, (2) thick-walled chemoreceptors and (3) thin-walled chemoreceptors. Tactile hairs and thick-walled chemoreceptors are present on all of the 40 or more flagellar subsegments while thin-walled chemoreceptors are limited to about one-third of them. Thin-walled chemoreceptors are present on subsegments nine and ten, one of the subsegments between 15 and 20 and from approximately the thirtieth subsegment to the distal end of the antenna. A description of each of these sense organs is given. No coeloconic or campaniform sense organs were found.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Cytoarchitecture of the choroid plexus of the third ventricle and the paraphysis was investigated in some lower vertebrates to compare the histologic characteristics of these organs. Both epithelia are similar in appearance in the same class. Minor microscopic variations exist in the different classes of vertebrates, but do not provide a fundamental distinction between the two organs. The epithelia, moreover, have similar staining properties, contain mucicarmine- and PAS-reactive materials, and are derived from a common neuroepithelium. Tubules are identified in the choroid plexus and in the paraphysis; all are similarly formed by simple folding of epithelium on the surface into the stroma. The paraphyses in all vertebrates studied contain villi similar to those seen in the choroid plexus. Cilia are identified in both choroidal and paraphyseal epithelia, and are not an indication of degree of epithelial differentiation. Many types of epithelium are noted in both organs during histologic differentiation as well as in the mature stage. Functionally, the choroid plexus is active in both secretion and absorption. Accumulation of particulate material within the epithelial cytoplasm may indicate phagocytic as well as absorptive activity of cells. Based on a common neuroepithelial origin and similar histochemical properties, we conclude that the paraphysis is a modified choroid plexus. The velum transversum is an arbitrary boundary between diencephalon and telencephalon, and is itself formed of choroid plexus. The medial telencephalic ventricle is the rostral portion of the third ventricle. All neuroepithelial infoldings at the rostral end of the diencephalic roof including the velum transversum are intraventricular choroid plexuses; the neuroepithelial outpouchings in this region are the extraventricular choroid plexuses (paraphysis) of the diencephalon.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The left ovary of the bonnethead shark, Sphyrna tiburo, is rudimentary, and the right ovary supplies both oviducts which share a common ostium situated in the falciform ligament. Preceding ovulation the nidamental gland of each oviduct hypertrophies and the caudal two-thirds of each oviduct is modified to form a uterus. In the Florida-Caribbean area Sphyrna tiburo probably mates in March and 3-7 eggs are fertilized in the vicinity of the nidamental gland of each oviduct.The developing embryo is nourished during the first 3-4 months of gestation by yolk stored in its extensive yolk sac. Approximately three and one-half months after fertilization, the distal portion of the yolk sac becomes convoluted and interdigitates with deep folds in the uterine wall to form a yolk-sac placenta. As the placenta develops, the maternal uterine epithelium is reduced from columnar cells to squamous cells, and the foetal yolk-sac epithelium is reduced from columnar and cuboidal cells to squamous cells. Exchange between the maternal and foetal blood systems takes place through maternal endothelium, reduced maternal epithelium, egg-case membrane, reduced foetal epithelium, and foetal endothelium.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 347-358 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Histochemical methods for mucins were applied to the ovaries of 23 dogs.Solid and hollow groups and cords of epithelial cells (subsurface epithelial structures, SES) in the outer part of the cortex regularly showed evidence of mucin secretion. Intracytoplasmic, sialic acid-containing, acid mucin secretion droplets were seen in solid and hollow SES, and secretion was present in both closed lumina and those opening onto the surface.Intracytoplasmic droplets in the cells of SES were distinctive, and similar droplets were not found in the cells of any other ovarian epithelial component. The secretion of SES was not shown to possess distinctive histochemical features.Mucin production was also observed in follicles, corpora lutea and rete tubules.The significance of ingrowth from the ovarian surface epithelium in adult life, and of secretory activity by the cells of SES, are discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This is the last of a series of observations involved in a comparative histological study of the ultimobranchial body in vertebrates. Complete serial longitudinal or transverse paraffin sections were made of formol alcohol, Bouin's, and formalin-fixed ultimobranchial and thyroid tissues that had been removed from adult specimens of the cat, cotton rat, ground squirrel, Guinea pig, kangaroo rat, bushytailed wood rat, rabbit, and raccoon. The alcian blue-PAS, aldehyde fuchsin-alcian blue, mucicarmine, alcian blue-safranin, Best's carmine, and toluidine blue staining procedures show that the glandular mammalian ultimobranchial tissue is capable of producing considerable amounts of various mucosubstances, particularly the acid mucopolysaccharides, and other carbohydrate-containing materials. The carbohydrate moiety has been histochemically identified as mucopolysaccharides possessing acidic groups, those having both carboxyl and ester sulfate groups; and as glycogen, muco-and glycoproteins and other carbohydrate-protein complexes. The differences in the intensity and localization of a given staining reaction reflect not only individual and species variations but also significant differences in the position of the ultimobranchial tissue in relation to the thyroid gland. An accessory thyroid lobule found near parathyroid IV and thymus IV in a bushy-tailed wood rat may represent a cystic manifestation of the ultimobranchial body because its follicles varied greatly in size and were lined by a thick stratified squamous epithelium. The possible hormonal mechanisms (TSH, thyroxine) involved in the regulation of ultimobranchial activity are discussed in relation to the gland's production, storage, and release of mucopolysaccharides and other secretory substances.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 11-41 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The axial filament of Sciara coprophila does not conform to the usual 9 + 2 filament pattern but consists, rather, of as many as 76 pairs of filaments which decrease in number from the anterior to the posterior region of the sperm. It is first seen at the base of the head in the shape of an indented oval. The axial filament varies in configuration along the remaining length of the sperm as one whorl or two connected whorls of filament pairs.The other structures of the sperm revealed by the light and electron microscopes are a homogeneous, dense, spear-shaped nucleus, a row of spherical dense bodies in the middle piece enclosed by the axial filament and of unknown nature and function and a single mitochondrial derivative.The mitochondrial nebenkern derivative consists of a large electron transparent region bordered by cristae and a smaller paracrystalline region located adjacent to the axial filament. The derivative arises as paracrystalline material in a medial nuclear indentation. The electron transparent material is first seen at the anterior end of the middle piece.Unlike other known insect sperm, but reminiscent of sperm capacitation in mammals, sperm maturation is completed in the spermathecae of Sciara 7 to 9 hours after insemination. It consists of the acquisition of sperm motility and elimination of the electron transparent region of the mitochondrial nebenkern derivative. The electron microscope reveals in mature sperm that the axial filament doublets have changed configuration and consist of a single whorl which encloses the paracrystalline rod. The process by which the major portion of the nebenkern derivative is eliminated occurs in four identifiable stages. Since sperm maturation does not appear to be intrinsically controlled, factors in the spermathecal fluid may play a role in its completion.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The vascular architecture in the rabbit uterus was studied during pseudopregnancy. Uteri at 2, 3, 4, 6, 7, 8, 9, 11, 13, 16, 17, 18, 20, 24 and 28 days after sterile mating were subjected to one of four techniques: neoprene latex casts, transparent sections, frozen sections, and histological sections. Measurements were made microscopically of the thickness of myometrium and of the subepithelial capillary plexus in the different mucosal folds. In the estrous rabbit, the circular arteries in the uterine muscular layer give off arterioles which pass upwards, with a few branchings through the endometrium to the uterine lumen. These arterioles reach the surface of the mucosal folds and break up into the subepithelial capillary plexus. This plexus is connected to the tips of the venules which run down through the endometrium to the endometrial vascular plexus at the base of the endometrium: some of the venules connect with the circular venous vessels in the muscular layer. With advanced stages of pseudopregnancy, the capillaries among the glands become stretched and elongated. Maximal branching of the folds occurs at 4 to 9 days of pseudopregnancy. The “branching activity” was consistently higher in the placental than in the periplacental or in the obplacental folds. Such changes reached a maximum at 6 to 7 days p.c., after which the capillaries became gradually shorter and tortuous. The development of arterioles in the mucosa was marked at 3 to 6 days p.c. The thickness of the plexus in the periplacental fold and in the obplacental fold as a percentage of the thickness in the placental fold was highly correlated with the stage of pseudopregnancy. At 9 to 11 days p.c., these ratios reached a minimum of 70 to 80%.
    Zusätzliches Material: 23 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 19-58 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A thin, compressible, lateral suture and ventral plate overlap permit limited movement of the thick and rigid dorsal and ventral plates of Fuscouropoda agitans. Seven pairs of large dermal glands debouch onto the surface. Trochanteral rotation permits defensive leg adpresion and an insectan type of ambulation. The complex hypopharynx-pedipalpal-coxae has a buccal and cheliceral cavity separated by an atriculated epipharynx. The pharynx is Y-shaped in cross section. Extensive paired salivary glands lie above the very long and dexterous 3-segmented chelicerae, and a large pair of coxal glands debouch on coxae 1. From four blunt-ended tracheae, bundles of unbranching tracheoles extend in specific tracts to all organs. The ventriculus is small with three pairs of large caeca; a tightly packed single layer of digestive cells individually enlarged to absorb-phagocytize and digest the food. A typical mesostigmatid excretory tube is present. A typical acarine synganglion is present; mixed nerves have a basal swelling. A postulated neurosecretory organ arises from the pedipalpal nerve. The oocytes enlarge within funicular stalks from the walls of the small median ovary. A large spermatophore is stored in the seminal vesicle; fertilization occurs during oviposition. A tension hinge partially opens both male and female genital plates; closure effected by muscles acting on very long genital plate apodemes. Within sequentially produced spermatogonial cysts of the testes, meiosis is completely synchronous. A large, multilobed male accessory gland produces a large volume of seminal fluid; a mixture of at least four secretions. The origins and msertions of the body wall, genital organ, digestive tract, mouthpart and leg muscles are listed and illustrated. A comparison of anactinotrichid and actinotrichid mites indicates fundamental and consistent morphological differences in aspects of the cuticle, leg articulations, digestive system, excretory system, reproductive system and coxal glands.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 279-297 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: An investigation of the structure of the iridescent scales of the green hairstreak, Callophrys rubi, reveals an internal lattice which is probably cubic close-packed in form. We present a model which explains the formation of the lattice in terms of packing of spheres and surface tension forces and generalize these results to internal structures in other Lepidopteran scales.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: There are 36 to 42 taste bristles on each half of the labellum of Drosophila melanogaster; most of them are two-pronged with a pouch between them. Some end bluntly with a pore at the tip.Each taste-bristle has two lumina: one is circular, the other crescent-like in cross section. In most bristles four dendrites of chemoreceptor neurons run along the circular lumen. In five to seven taste-bristles only two chemoreceptor neurons are found. A mechanoreceptor neuron sends a dendrite to the base of each taste-bristle.The dendrites are surrounded by four concentrically-arranged sheath cells. The inner cell secretes the cuticular sheath; cells II and III are presumably two trichogens, one secreting the bristle material around the circular lumen, the other around the crescent-like lumen. Cell IV, especially rich in bundles of microtubules, secretes the cuticle of the socket, and corresponds to the tormogen. The neurons have the typical structure found in insect sensilla. In many sensilla one neuron is less electron-dense than the others and may be the water-sensor.On the medial side of the labellum between the pseudotracheae are rows of taste pegs covered by folds. In each peg one chemoreceptor and one mechanoreceptor are found.The number of axons in each labial nerve agrees with the total number of dendrites in all taste organs of each lobe.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 423-451 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Stichopus moebii, a sea cucumber, has a closed circulatory system which is unique in its degree of development for the phylum Echinodermata. The gross anatomy, histology and fine structure of the system were studied. Blood vessels consist of a coelomic surface of ciliated epithelium, a layer of muscle and nerve cells, followed by connective tissue and luminal lining of endothelium. Basically the blood vascular system consists of two major vessels running parallel to the gut: the dorsal vessel pumps colorless blood via the vessels within the walls of the intestine into the ventral vessel. There are two specialized areas of the circulation: (1) At the upper small intestine 120 to 150 muscular single-chambered hearts pump blood from the dorsal vessel into a series of intestinal plates. (2) At the lower region of the small intestine the vasculature is associated with the left respiratory tree. Blood passing from the dorsal pulmonary vessel can take two routes to the gut, it either passes through myriads of minute respiratory shunt vessels entangled with the respiratory tree or it passes through a unique follicle network consisting of tiny channels periodically dilated into chambers filled with iron deposits, necrotic cells and developing coelomocytes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 639-679 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Anatomical components of afferent innervation in the rim of the octopus sucker are described. In the sensory epithelium under the smooth cuticle two associated ciliated receptor cell-types (presumably chemosensitive) occur in clusters. A third ciliated receptor cell-type under the toothed cuticle may be a mechanoreceptor. A non-ciliated receptor cell-type of unknown function, under the toothed cuticle, is characterized by a microvillus-lined apical canal containing dense granular material. The axons of the latter two receptors go directly into large nerve tracts which nm through the infundibular muscle and on to the ganglion of the sucker. The axons of the first cell-types terminate on interneurons either in the base of the epithelium or below the epithelium. All the interneurons of the basal region of the epithelium migrate centripetally and develop into encapsulated interneurons. Within the epithelium, fine fibers provide collateral contact among cluster receptors. Collateral interaction among basal and encapsulated interneurons occur in the infundibular plexus. The microanatomy of the rim of the sucker suggests that chemosensory cues are funneled into the interneurons where they are concentrated into integrated signals, while other sensory input is probably sent directly to the ganglia of the sucker and/or arm.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 727-761 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The pyloric region of Eosentomon and Acerentomon (Insecta, Protura) is described. In both species the posterior cells of the midgut carry short microvilli. Beneath the epithelial cells there is a muscular pyloric sphincter for closing the intestinal lumen. Behind the sphincter is a wide pyloric chamber lined by cells with very long microvilli which point anteriorly toward the midgut. These cells regulate the passage of the intestinal contents into the hindgut. Secretions from the Malpighian papillae are emitted into the gut at this level. In Eosentomon three regions (R1, R2 and R3) are visible in the Malpighian papillae, whereas in Acerentomon region R1 is lacking. The R1 region contains secretory cells with elaborate glycoprotein-containing granules. The R2 region is composed of cells somewhat resembling the secretory cells of Malpighian tubules of insects. Presumably R1 and R2 cells emit secretions into the central cavity of each papilla. Cells of R3 form a duct for the secretion. It is suggested that the R2 region represents a basic excretory region, common to Protura, whereas the R1 region, in Eosentomon, may be a specialized area performing supplementary excretory functions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 785-803 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This manuscript describes in precise detail the ultrastructural alterations produced as a result of laser microirradiation of nucleoli and nucleoplasm of tissue culture cells. Because of the general difficulty of single cell recovery, flat embedding, and serial sectioning, very few studies have ever been conducted on microbeam irradiated cells; yet the use of the microbeam technique has become widespread in functional studies of the nucleus. The results presented here demonstrate two classes of lesion material: small spherical electron dense bodies 0.05-0.02 μm in diameter and a larger, more irregular electron dense material up to 1 μm in length. The occurrence of these different types of lesion materials is described in control irradiated nucleoli and nucleoplasm, irradiated nucleoli and nucleoplasm in quinacrine treated cells, irradiated nucleoli and nucleoplasm in actinomycin D treated cells, and irradiated nucleoli and nucleoplasm in combined actinomycin D and quinacrine treated cells. In all the cells in which actinomycin D was employed, nucleoli were selectively irradiated in either their granular or fibrillar zones. The results of the ultrastructural studies are discussed in light of earlier functional studies.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 843-859 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The general form and adaptation of the digastric muscle in carnivores are reviewed and discussed. The digastric muscle differs from the general plan in certain aquatic carnivores and felids. In the pertinent aquatic species the muscle is enlarged. The observations suggest that the enlargement is an adaptation for rapidly opening the jaws against the resistance of water. In felids, the insertion of the muscle is much farther forward than in most other carnivores. The observations suggest that the development of short jaws in felids necessitated a compensatory anterior relocation of the digastric insertion in order to preserve the ability to achieve a large gape.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 889-899 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Homolid crabs (Hypsophrys) from water deeper than 700 m in the Straits of Florida and Arabian Sea have smooth darkened oval spots contrasting with the surrounding roughened integument on inner and outer surfaces of each pincer at the base of the fixed finger. Cuticle is thinner over these spots than over surrounaing tissues. Beneath each spot is an organ composed of two markedly contrasting layers of tissue: (1) an outer, densely staining layer of tightly packed tubules, relatively straight and perpendicular to the overlying surface proximally but progressively convoluted and narrowed distally, finally ending blindly in association with the overlying thinned cuticle; (2) an inner layer of relatively large, eosinophilic, irregular cells with dark nuclei also trending at a right angle to the integument and bulging into the hemal sinus of the hand but separated from it by an epidermal lining. Droplets secreted from the inner layer apparently move into and along the tubules. Similar organs are known in no other crabs. The function is unknown but the structure suggests that they may be photophores.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 327-335 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The swimbladder system of the plainfin midshipman consists of a gas-filled bladder and two intrinsic sonic muscles which are attached to the bladder at opposite sides. An experimental and analytical study was conducted to define the physical characteristics of this dynamic system, and to relate these characteristics to radiated acoustical pressure pulses. Results indicate that the system has two degrees of freedom, being comprised of two inertial, stiffness and damping components; the first and second mode components of a 23.1-centimeter midshipman are 0.002 and 0.019 kg (inertial) 2130 and 106,000 newtons per meter (stiffness) and 0.25 and 0.10 (damping) respectively. This system is excited by the sonic muscle forcing function which equals \documentclass{article}\pagestyle{empty}\begin{document}$ 0.00236{\rm}\sin \frac{{2\pi {\rm t}}}{{0.0045{\rm}\sec}}{\rm newtons}. $\end{document}Two system frequency response peaks were observed; the first was 110 hertz, at the flat section next to the sonic muscle, and was very near the repetition frequency of the sonic muscle pulses; the second was 350 hertz, at the hemispherical section, which was the frequency of the acoustical pressure pulse. These phenomena describe a dynamical system closely “tuned” to its forcing function, and a system which is highly responsive to acoustical pressure pulses radiated by neighboring midshipmen. The acoustical pressure pulse coincides in wave form with the hemispherical bladder wall acceleration.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 763-783 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of a well studied insect chemosensory unit is presented in this report. Two separate lumina are present in this chemosensory unit, the trichogen and sensillar lumina. The fluid within the trichogen lumen exclusively bathes the dendritic terminals, and may be involved with the reception and/or modulation of environmental stimuli. Cytoplasmic extensions of the trichogen cell which line the trichogen lumen may be involved in the production of the cuticular sheath. The sensillar lumen is bordered by the tormogen and a sleeve cell, and is continuous with the unoccupied channel of the setal shaft. Functions for the various cellular components of the blowfly chemoreceptor sensillum are offered.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study indicates that eggs containing calcium carbonate crystals occur in at least 36 of the 65 known families of the land snails (class Gastropoda: order Stylommatophora). Eggs from 22 of these families were available for examination. The x-ray diffraction data, available for the first time for 21 of these families, shows that these egg shells are all made of calcite only, or of a combination of calcite with smaller amounts of aragonite. All of the snail (body) shells examined were made of aragonite only. This is the first ultrastructural investigation of these egg shells, and it indicates that the eggs exhibit enough structural diversity to allow identification of parental animals to genus, and often to species level solely on the basis of egg shell ultrastructure.All of the calcified eggs may be divided into two groups: (1) partly calcified, with discrete crystals of CaCo3 dispersed in the jelly layer, and (2) heavily calcified, with a hard, brittle egg shell made of fused crystals of CaCO3 much like an avian egg. Both types of calcified eggs occur in oviparous as well as in ovoviviparous snails. Because of the wide distribution of calcified eggs in the Stylommatophora, and because of the occurrence of heavily calcified eggs in ancient families such as Partulidae, Endodontidae, and Zonitidae, the calcified egg is viewed as a primitive land snail trait associated with terrestrial adaptation. The function of the calcified egg shell, in addition to mechanical support of egg contents, is to supply the developing embryo with enough calcium to form the embryonic shell by the time of hatching.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 483-491 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Freshwater sponges, Corvomeyenia carolinensis Harrison, were placed into tap water to induce degenerative reduction body formation. Reduction bodies were examined using light and electron microscopy in order to define their histochemical and ultrastructural characteristics. The reduction body of freshwater sponges is an extremely simple developmental system consisting primarily of an archeocyte reserve delimited by a simple squamous pinacoderm. The freshwater sponge reduction body displays many similarities to overwintering phases of marine sponges. The system presents an unusually straightforward vehicle for investigations of degeneration and regeneration as processes in developmental biology and may represent a reasonable vehicle in which to examine the process of the genesis of lysosomes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The aquiferous systems of three common, coastal, marine Demospongiae, Halichondria panicea (Pallas), Haliclona permollis (Bowerbank) and Microciona Prolifera (Ellis and Solander), are analyzed by measurements of cross-sectional areas of conducting elements. The patterns in demosponges of extremely different organizational morphologies are found to be quantitatively similar. The porocyte nature of the ostia is established for all three species. Choanocyte chamber densities range from 1 to 1.8 × 107 chambers ml-1 with 57 to 95 choanocytes per chamber (means). Cross-sectional area of the intervillar space of the choanocyte collars is calculated to be 12 to 56 times the lateral surface area of the specimen. Velocities of water movement through specific elements of the aquiferous system are calculated from cross-sectional area data and measured oscular flow of Haliclona permollis. The calculated Reynolds numbers lie below the critical value and fluid flow is thus considered laminar throughout the aquiferous systems of these sponges.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Serial histological sections of kangaroo rats of postnatal ages 0-, 3-, 7-, 10-, and 14-days were prepared and studied. At birth the middle ear is mostly filled with mesenchyme and small in size, having only a small hypotympanum and a very small epitympanic recess. During the first postnatal two weeks, much of the hypertrophy found in the adult middle ear develops. Because an entotympanic element is never formed, the previously called entotympanic chamber is here renamed the hypotympanum. The epitympanic recess greatly expands to form what has been called the dorsal (or anterior) mastoid sinus. Since this chamber has no relation to the mastoid, it is here renamed the epitympanum. Posteriorly, the previously called posterior mastoid sinus develops from the growth of the hypotympanum into and beyond the region of the posterior and horizontal semicircular canals. In development and adult position it is comparable to the primate antrum and so is here renamed the antrum.At birth the organ of Corti is very immature but its major cell types can be identified. During the first two weeks of development the following events occur: (1) the vas spirale disappears, (2) the inner spiral sulcus cells atrophy, (3) the hair cells and supporting cells mature, (4) the cells of Hensen differentiate with their apical processes elevating the reticular lamina, (5) the innermost cell of Claudius migrates under and supports the Hensen's cells, and (6) the hyaline mass of the zona pectinata of the basilar membrane loses its connective tissue cells and expands in size. The developmental events support the previous description and identification of Hensen's and Claudius' cells.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 147 (1975), S. 61-88 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A consideration of head development in two species of Esox, lucius and americanus (ssp. vermiculatus) representing the two subgenera Esox and Kenozoa respectively, focused on the significance of the variations of the latero-sensory canal system, its associated bones, and other skeletal elements. In living forms only aspects of “regression” or specialization can be studied. Canals tend to be reduced to pit lines first at their termini but can be broken in their course. Pit lines range from nearly canals to surface structures, or even fail to develop. The number of neuromasts varies. Canal bones develop from two centers: neuromast related and deeper membranous centers which may have no relationship to neuromasts. Tooth-bearing and non-canal-related dermal bones have only membranous (original) centers. The number of neuromasts associated with a bone usually does not affect its development or form. In the case of the circumorbital bones, the extrascapulars, and the nasal, a one to one relationship has developed by regression - towards the development of the latero-sensory component only. The idea that reductions in bone number are commonly traceable to fusion is rejected although examples of fusion are known. Most bones that disappear are simply lost (no blastema or other evidence of their presence seen in development). The relationship between dermal bone and chondral bone is examined and there is evidence of the former giving rise to the latter. The ontogenic order of appearances shows a feeding (functional) correlation.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 147 (1975), S. 89-107 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The nucleus rotundus of 21 species of teleosts was studied by a modified Bodian and the Golgi method to clarify the histological organization, with special reference to the cell lamination and the glomerular formation.The common components of the nucleus in all species are as follows: a thick fiber bundle which comes from the commissura horizontalis and enters the nucleus from the dorsal surface, many small cells, large cells, glomeruli, and a surrounding fibrous capsule. The nuclei of all species studied are classified into three types mainly on the distribution of the small cells, and to a lesser degree on the location of the large cells and the glomeruli.The first type of nucleus has small cells. large cells and glomeruli throughout its extent. In the second type of nucleus, many small cells form a peripheral cell layer, while the large cells and glomeruli are found all over the nucleus.The third type of nucleus is clearly laminated. It is composed of four layers arranged concentrically around a central fiber net in the following order: a glomerular layer, a fibrous layer, a small-cell layer, and a peripheral fibrous capsule. In some species, the large cells are located in the fibrous capsule, and all glomeruli contain a star-like structure, which corresponds to the tips of the large cell dendrites.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 147 (1975), S. 439-457 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The accessory muscle of the walking leg of the horseshoe crab, Tachypleus gigas, was examined electron microscopically. The muscle fibers vary in size but are small in diameter, when compared with other arthropod skeletal muscles. They are striated with A, I, Z and poorly defined H bands. The sarcomere length ranges from 3-10 μm with most sarcomeres in the range of about 6 μm. The myofilaments are arranged in lamellae in larger fibers and less well organized in the smaller ones. Each thick filament is surrounded by 9-12 thin filaments which overlap. The SR is sparse but well organized to form a fenestrated collar around the fibrils. Individual SR tubules are also seen among the myofibrils. Long transverse tubules extend inward from the sarcolemma to form dyads or triads with the SR at the A-I junction. Both dyads and triads coexist in a single muscle fiber, a feature believed to have evolutionary significance. The neuromuscular relationship is unique. In the region of synaptic contact, the sarcolemma is usually elevated to form a large club-shaped structure containing no myofilaments and few other organelles. The axons or axon terminals and glial elements penetrate deep into the club-shaped sarcoplasm and form synapses with the fiber. As many as 13 terminals have been observed within a single section. Synaptic vesicles of two types are found in the axon terminals.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 23-31 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: When cervical segments 14 to 15 of the chicken spinal cord are cut transversely and studied by routine histological and histochemical methods, an onion-shaped region, filled with thread-like fibers, if seen to surround the ependymal cells of the central canal and to be bounded laterally by the neural elements of the spinal gray matter. This area is negative for succinic dehydrogenase, beta-hydroxybutyrate dehydrogenase and cholinesterase activity, but very strongly periodic acid-Schiff positive. Diastase controls show the positive material to be glycogen. Parasagittal sections through this cervical region and into the upper thoracic cord, show the glycogen-rich region to extend longitudinally throughout the region. Because of its location and histochemical characterization, which, He similar to that of the ventral portion of the glycogen body, the term brachial glycogen budy is proposed for this structure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 1-21 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Anterior dorsal ventricular ridge (ADVR) is a major subcortical; telencephalic nucleus in snakes, Its structure was studied in Nissl, Golgi, and electron microscopic lrerarations in several species of snakes. Neurons in ADVR form a homogeneous population. They have large nuclei, scattered cisternae of rough endoplasmic reticulum in their cytoplasm, and bear dendrites from all portions of their somata. The dendrites have a moderate covering of pedunculated spines. Clusters of two to five cells with touching somata can be seen in Nissl, Golgi, and electron microscopic preparations. The area of apposition may contain a series of specialized junctions which resemble gap junctions. Three populations of axons can be identified in rapid Golgi preparations of snake ADVR. Type 1 axons course from the lateral forebrain bundle and bear small varicosities about 1 μ long. Type 2 axons arise from ADVR neurons and bear large varicosities about 5 μ. long. The origin of the very thin type 3 axons is not known; they bear small varicosities about 1 μ. long. The majority of axon terminals in ADVR are small (1 μ. to 2 μ long), contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates on dendritic spines and shafts and on somata. A small percentage of terminals are large, 5 μ in length, contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates only on dendritic spines. A small percentage of terminals are small, contain pleomorphic synaptic vesicles, and form symmetric active zones. This type of axon terminates on dendritic shafts and on somata.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 33-63 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Tooth development and replacement in fetal and adult viviparous caecilians (Amphibia: Gymnophiona) are described and analyzed according to current theories of tooth succession. The fetal dentition differs from that of the adult in morphology, position, and function. Teeth are used by fetuses to scrape the oviducal epithelium, thus stimulating the secretion of a nutrient substance. Fetal dentitions vary in morphology and position in different species. The ontogeny of teeth of several species is described and the patterns of addition of loci and of replacement are analyzed, Loci are added both posteriorly along the jaw and between existing loci as the jaw grows prior to ossification; subsequently addition is restricted to the posterior part of the jaw. Tooth replacement is alternate. The several rows and patches of teeth are the result of retention of replacement series on the dentigerous elements. Tooth development and replacement in a series of juveniles and adults of different sizes in a single species are also considered. Post-fetal patterns of development and replacement are similar to those seen in larvae and adults of oviparous species. Variation in numbers of teeth and proportions of teeth at particular stages occurs ontogenetically and among individuals of the same size, though proportions occur in a similar pattern throughout the series. The general pattern of tooth replacement in fetuses and adults can be explained by either Edmund's Zahnreihen theory or by Osborn's Tooth Family theory, but replacement in fetal tooth patches and the fetal-adult dentitional transition are explained by neither.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 65-87 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In Brallchiobdella pentodonta Whitman meiosis begins in follicles containing 16 spermatogonia. In each follicle the spermatogonia are connected by cytoplasmic bridges to a central anuclear cytoplasmic mass or cytophorus. They develop synchronously. Synaptonemal complexes are present in the primary spermatocytes. Spermatids contain a large globoid paranuclear body consisting of an acrosomal granule and coiled tubules which evidently receive the contents of the acrosomal granule and are considered the acrosome carrier. The spermatids separate from the cytophorus only when differentiation is completed.The ripe spermatozoon is relatively long. It has anteriorly the coiled tubules, followed by the nucleus, the mitochondrial sphere and the distal centriole from which the flagellum originates, A coiled ribbon-like structure encloses the flagellum along its entire length while a manchette of microtubules surrounds all the other structures of the sperm.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 89-135 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The muscles and bones of the pectoral fin of Serrasalmus nattereri, the piranha, resemble those of generalized, lower teleosts with specializations related to a body shape adapted for high-speed carnivory; the pectoral fins being highly mobile with strong ligaments to the rays. The presence of two occipital nerves appears primitive, while the emergence of the subclavian artery within the branchial cavity, as in Gasteropelecus sternicla, appears specialized. The muscles and bones of the latter fish, a fresh-water flying fish, are specialized for self-propelled, aerial flight in the fusion of the right and left girdles greatly expanded for insertions of complex appendicular (flight) muscles, and in the consolidation of the rays and radials into one functional unit moving vertically in flight though contraction of vertical, massive ventral flight muscles. The bony pectoral anatomy of Electrophorus electricus, the electric eel, is specialized in having a mobile joint between the primary girdle and the cleithrum, the former being suspended vertically from the cleithrum by ligaments. The proximal radials and rays are very numerous and vertically aligned. The cleithrum is shaped to accommodate the extensive sternohyoid and pharyngocleithral muscles. The sheet-like appendicular muscles extend beyond the special joint and control its movement. The deeper muscles do not cross this joint. The arterial system is specialized in lacking a deep brachial artery.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 1-31 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cibarial food pumps of aquatic Heteroptera contain specialized epipharyngeal triturating devices. In the Naucoridae, striated bands and transverse plates triturate particles against the underlying hypopharynx. Anterior to them lie a pair of oblique folds which play an accessory role. The gross morphology of these devices is very similar in representatives of five genera of typical Naucoridae (Ambrysus, Pelocoris, Limnocoris, Cataractocoris, Cryphocricos) and differs from that of the atypical genus Aphelocheirus.The scanning electron microscope reveals additional differences between Aphelocheirus and the typical genera as well as variations, among the latter, which are not visible with the stereoscopic microscope. The oblique folds of the typical Naucoridae are well developed and contain processes for trapping particles; in three genera the region posterior to the folds is also modified. In Aphelocheirus only the latter region appears to trap particles, and the oblique folds are smooth and weakly developed. The striated bands of all genera bear ventral ridges arranged into transverse zones with precise patterns. The fourzoned bands of Aphelocheirus have a very different pattern than the two-zoned bands of the other genera. Among the latter, Cryphocricos has a simpler pattern of ridges than the other typical Naucoridae. The ventral surfaces of the transverse plates are highly modified in Aphelocheirus and less so in the other genera; those of Cryphocricos differ from those of the other Naucoridae.The fine structure of the cibarial epipharynx supports the views of some systematists that (1) Aphelocheirus should be placed in the monogeneric Family Aphelocheiridae rather than in the Naucoridae, (2) Cryphocricos represents a different subfamily than the other four typical Naucoridae, and (3) Cataractocoris belongs in the same subfamily as Ambrysus rather than with Cfyphocricos.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 53-71 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by fonnation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments caused the collagen to assemble. Neither the polymerization nor ordering of collagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 265-277 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve.In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes.The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 421-435 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Whole ovaries from 16-day fetal mice were cultured for 6 to 20 days and then transplanted to the kidneys of ovariectomized adult mice where they remained for one to four weeks. After three weeks in the host's kidneys, many follicles developed within the transplants and became vesiculated. Many of the oocytes within these follicles had formed the first metaphase spindle of meiosis and several had completed the first polar body. Host mice bearing transplants that contained vesiculated follicles showed uterine stimulation and keratinization of their vaginae. However, ovaries that had been in culture for more than ten days before transplantation showed a limited response to the gonadotropins and never matured sufficiently to stimulate the host's reproductive tract. No ovulations occurred in any of the transplants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 1-16 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Six types of hemocytes were identified in fifth instars of the Indian meal moth, Plodia interpunctella. The morphology of these cells was characterized by phase contrast and electron microscopy, with Sudan black B, Giemsa, Janus green B, and periodic acid-Schiff staining. Reaction of the hemocytes with seven fluorescing lectin conjugates revealed distinctive binding patterns by their plasma and nuclear membranes and cytoplasmic inclusions. A direct line of descent from prohemocytes to plasmatocytes to granulocytes is suggested from these morphological observations.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 33-56 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: New fossils of the rare Oligocene mammals Xenocranium and Epoicotherium add information on their skulls and provide the first information on their postcranial skeletons. These epoicotheres, the latest surviving palaeanodonts, have numerous fossorial adaptations and must have been predominantly subterranean. Their skeletal specializations are similar to, and equal or surpass in degree of development, those of most living fossorial mammals.Principal modifications of the skull are the expanded, domed occiput with broad lambdoid crests, hypertrophy of the malleus-incus and related changes in other ear components, reduced eyes, and (in Xenocranium) a flaring, upturned, spatulate snout. The neck was strengthened by synostosis of the 2nd through 5th cervical vertebrae. The forelimb elements have exaggerated crests, processes, and fossae for muscles used in digging or in stabilizing certain joints. The scapula has a high, stout spine with bifid acromion, a “secondary spine,” and an expanded postscapular fossa for attachment of the teres major muscle. The humerus has an elongate pectoral crest, large lesser tuberosity, long entepicondyle, and large hooklike supinator crest. The enormous incurved olecranon process of the ulna provided insertion for the massive triceps and origin for the carpal and digital flexors, and the latter gained mechanical advantage by incorporating in its tendon a large carpal sesamoid. In the greatly shortened hand, digit three is largest, with its metacarpal and proximal phalanx fused and its claw-bearing ungual-phalanx very large.These traits indicate that Xenocranium and Epoicotherium were among the most specialized “rapid-scratch” diggers ever to evolve. Their remarkable convergence to chrysochlorids reflects a similar mode of digging, with extensive use of the snout for loosening and lifting soil when making shallow foraging burrows. For deeper burrowing, the forelimbs probably loosened the soil while the rear limbs moved it behind. Like many extant subterranean mammals, Xenocranium and Epoicotherium were essentially sightless, but they were specialized for low frequency sound reception. Their extinction may have been due to a combination of environmental change and competition with other fossorial animals, such as proscalopine insectivores and rhineurid amphisbaenians.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 119-130 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In the sprawling gait of Varanus exanthematicus, the bicondylar distal humerus requires both the radius and ulna to rotate in the same direction. The joints between the radius and radiale and between the ulna and ulnare and pisiform accomodate these specific rotations. A ligament system between radius, ulna, radiale, and ulnare causes the radius and ulna to approximate one another during external rotation of the forearm. This approximation is conveyed distally resulting in a narrowing of the hand during external rotation of radius and ulna or during pronation of the free hand. The significance of these and related linkages is discussed.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 57-64 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The overall anatomy of Neodasys as well as data for hemoglobin-containing cells are described. Hemoglobin-containing cells are shown to be mesodermal specializations constituting approximately 14% of the animal's total body volume (4.87 ± 104 μl). These globular cells (10-14 μm) are situated in two longitudinal rows, each dorsolateral to the straight gut. Branches from the cells enwrap perikarya of muscle and nerve cells whose mitochondria are found just below their respective plasmalemmata in intimate association with the hemoglobin-containing cells. The ground substance of the cytoplasm and nucleoplasm of these nearly organelle-free cells is extremely electron-dense and is presumed to represent the hemoglobin molecules. Locomotion analyses indicate that the cells can undergo a threefold change in linear dimension in 0.25 seconds, raising the possibility of convective mixing in these cells. Structural and ultrastructural comparisons with similar cells in adults of other species of Gastrotricha indicate that the hemoglobin-containing cells of Neodasys may be homologous to the socalled Y cells of other species, some of which contain myofilaments. A muscle-cell origin is considered for the evolution of hemoglobin-containing cells of Neodasys.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 91-100 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The digestive tract of the freshwater amphipod Hyalella azteca is a straight but differentiated tube consisting of foregut, midgut, and hindgut divisions. The foregut is subdivided into a tubular esophagus, a cardiac stomach, and a pyloric stomach. The cuticular lining of the cardiac stomach is elaborated into a set of food-crushing plates and ossicles, the gastric mill, while the pyloric cuticle forms a complex straining and pressing mechanism. Nine caeca arise from the midgut, seven anteriorly and two posteriorly. Four of the anterior caeca, the hepatopancreatic caeca, are believed to be the primary sites of digestion and absorption. The remaining caeca may be absorptive, secretory, or both. The much-folded hindgut wall is capable of great distention by extrinsic muscle action for water intake to aid in flushing fecal material out of the anus; such action also may stimulate antiperistalsis by intrinsic rectal muscles.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 131-142 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The proximal, intermediate, and distal convoluted tubules of the neprhon of Podarcis (= Lacerta) taurica were examined by electron microscopy. Proximal tubule cells have large, apical cytoplasmic protrusions and microvilli interpreted to function in urate secretion. Adjacent cells are bound apically by tight junctions and desmosomes but interdigitate in their basal region. This situation is repeated in the other tubules with significant differences in intercellular space width. The basal surfaces bear numerous cytoplasmic processes. The intermediate tubule has proximal and distal segments each with dark, ciliated, and light cells, the cuboidal dark cells with dense cytoplasm constituting the main bulk of the wall. As the cells of the proximal and distal segments resemble those of the proximal and distal convoluted tubules, respectively, the intermediate tubule is considered as a transition region. The ciliated cell body has two broad processes extending from the lumen, one to the basement membrane and one to a foot process of a light cell. The light cell is surrounded by dark and ciliated cells. It does not reach the lumen, but contacts the basement membrane through a process running below a ciliated cell to form a mushroom-shaped structure in tubule cross-section, the light cell process forming the stalk and a ciliated cell the cap. The cilia probably propel the glomerular filtrate towards the distal convoluted tubule. This latter tubule has initial, middle, and terminal zones, all nonciliated but with different lumen widths and cell shapes.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 153-169 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of the stylets produced by nine species of nemerteans has been examined by scanning electron microscopy (S.E.M.) and polarized light microscopy. Stylets are solid, nail-shaped structures that typically reach lengths of 50-200 μm. Each stylet is composed of a centrally located organic matrix surrounded by an inorganic cortex that contains calcium and phosphorus. When viewed at high magnifications, fine granules can be seen throughout the organic matrix, and the cortex appears to be composed of densely packed homo-geneous material. Fractured specimens and whole matrices isolated from decalcified stylets reveal a close correspondence between the shape of the organic matrix and that of the surrounding cortex. This similarity in morphology suggests that the organic matrix serves as a template during calcification of the stylet. The fact that abundant material can be seen in the core of incinerated stylets, and in the central region of stylets that had been soaked for several hours in sodium hypochlorite, supports the hypothesis that the organic matrix is also highly calcified. Polarization microscopy of nemertean stylets indicates that they are composed of a crystalline, rather than amorphous, form of calcium phosphate. The probable organization of the calcium phosphate crystals is discussed.
    Zusätzliches Material: 35 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 293-306 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The present study traces corneal morphogenesis in a reptile, the lizard Calotes versicolor, from the lens placode stage (stage 24) until hatching (stage 42), and in the adult. The corneal epithelium separates from the lens placode as a double layer of peridermal and basal cells and remains bilayered throughout development and in the adult. Between stages 32- and 33+, the corneal epithelium is apposed to the lens, and limbic mesodermal cells migrate between the basement membrane of the epithelium and the lens capsule to form a monolayered corneal endothelium. Soon thereafter a matrix of amorphous ground substance and fine collagen fibrils, the presumptive stroma, is seen between the epithelium and the endothelium. Just before stage 34 a new set of limbic mesodermal cells, the keratocytes, migrate into the presumptive stroma. Migrating limbic mesodermal cells, both endothelial cells and keratocytes, use the basement membrane of the epithelium as substratum. Keratocytes may form up to six cell layers at stage 37, but in the adult stroma they form only one or two cell layers. The keratocytes sysnthesize collagen, which aggregates as fibrils and fibers organized in lamellae. The lamellae become condensed as dense collagen layers subepithelially or become compactly organized into a feltwork structure in the rest of the stroma. The basement membrane of the endothelium is always thin. Thickness of the entire cornea increases up to stage 38 and decreases thereafter until stage 41. In the adult the cornea is again nearly as thick as at stage 38.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 176 (1983), S. 181-196 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Measurements have been made of those changes which lead to increases in the surface area of the intestine during the metamorphosis of three species of lampreys. Although the intestine of the Southern Hemisphere lamprey, Geotria australis, increases in length by 1.13 times and in diameter by 1.12 times, the main factor influencing the 5.71 times increase in surface area is the development of longitudinal folds. The contribution of the typhlosole to the internal perimeter of the intestine is less in most life cycle stages of G. australis than in Lampetra spp. The changes in the various intestinal measurements of the nonparasitic species L. planeri parallel those of the presumed ancestral parasitic species, L. fluviatilis, during the first six stages of metamorphosis. However, the longitudinal folds, but not the typhlosole, subsequently start regressing in L. planeri just after the time when the rate of gonadal development increases markedly. An account is also given of the pattern of fold formation and the development of the typhlosolar vein in G. australis.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 176 (1983), S. 247-247 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: No Abstracts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 176 (1983) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 176 (1983), S. 289-314 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The formation of the alimentary canal, nervous system, and of other ectodermal derivatives in the embryo of the primitive moth, Neomicropteryx nipponensis Issiki, is described. The stomodaeum is formed from an invagination in the medioposterior portion of the protocephalon. The proctodaeum arises as an extension of the amnioproctodaeal cavity. The midgut epithelium orginates from anterior and posterior rudiments in blind ends of the stomodaeum and proctodaeum. The decondary dorsal organ is formed in developing midgut. The development of the brain is typical of insects. The ventral nerve cord originates in large part from neuroblasts arising in 3 gnathal, 3 thoracic, and 11 abdominal segments. Intrasegmental median cord cells probably differentiate into both ganglion cells and glial elements of the ventral nerve cord; intersegmental cells appear not to participate in the formation of the nervous system. The stomatogastric nervous system develops from three evaginations in the dorsal wall of the stomodaeum, and consists of the frontal, hypocerebral, and ventricular ganglia, the recurrent nerve, and corpora cardiaca. Five stemmata arise from the epidermis on each side of the head. Five pairs of ectodermal invaginations are formed in the cephalognathal region to produce the tentorium, mandibular apodemes, corpora allata, and silk glands. Prothoracic glands orginate in the prothorax. Mesothoracic spiracles shift anteriorly to the prothorax during development. Oenocytes arise in the first seven abdominal segments. Invaginated pleuropodia are formed in the first abdominal segment.
    Zusätzliches Material: 61 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 178 (1983), S. 23-35 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Ultrastructural observations and glyoxilic acid-induced fluorescence of catecholamines indicate that tracts of axons lie at the base of the ciliary bands and run throughout their length in bipinnaria and brachiolaria larvae of Pisaster ochraceus. Two types of nerve cells occur at regular intervals within the ciliary bands. Type I nerve cells are associated with the axonal tracts, and type II nerve cells, which are ciliated, occur along the edge of the ciliary bands. Two prominent ganglia, which appear as accumulations of nerve cells and neuropile, occur on the lower lip of the larval mouth. Smaller ganglia occur irregularly throughout the ciliary band. Synapses were never clearly identified and were assumed to be unspecialized. Nervous tissues were also found associated with the esophageal muscles, the attachment organ, and the larval arms. Organization of the nervous system and its association with effectors suggest it controls swimming and feeding. Several similarities exist between the nervous systems of larval asteroids, larval echinoids, and adult echinoderms.
    Zusätzliches Material: 38 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 178 (1983), S. 1-21 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The gross morphology and electrical activity of the muscles of the pharyngeal apparatus of centrarchid sunfishes (Lepomis) are analyzed within a monophyletic clade containing species specialized for snail-eating. Outgroup comparisons of both structure and activity patterns of muscles permit examination of the relationship between specialized diet and function of the trophic apparatus. In most sunfish species, electrical activity in the pharyngocleithralis internus muscle significantly overlaps that in the retractor dorsalis muscle during pharyngeal transport, indicating that the upper and lower pharyngeal jaws retract together. Activity in the pharyngohyoideus, levatores externi, and levator posterior also significantly overlaps activity of the retractor dorsalis.Snail-eating is associated with derived morphological, behavioral, and functional features. The shell is crushed before pharyngeal transport, correlated with extensive overlap in activity periods of muscles. One species, Lepomis microlophus, possesses a highly stereotyped neuromuscular repertoire that does not vary with prey type. All prey, even fish and worms, are subjected to crushing. Lepomis gibbosus exhibits the crushing pattern of muscle activity only when feeding on snails. L. microlophus has a hypertrophied levator posterior muscle, but the lines of action of the pharyngeal muscles are similar to the primitive condition. Pharyngeal transport in this species is unique in that activity of the pharyngocleithralis internus alternates with that of the retractor dorsalis.In sunfishes, alterations in the central control of peripheral structures have produced major changes in the sequence in which homologous components of the structural network are activated.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 178 (1983), S. 77-87 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The scent apparatus of male Eldana saccharina is a glandular complex on the costal area of the forewing. It consists of two parts; glandular complex 1 is composed of five kinds of cells (epidermal cells, scale cells, glandular cells, supporting cells, duct cells); glandular complex 2 also shows five types of cells (epidermal cells, scale cells, glandular cells, duct cells, trichogen cells). The secretory products of the two parts are discharged into separate ducts which converge before opening onto the lower side of the wing. The male also has two prominent hair-pencils borne on the coremata and large secretory trichogen cells on the genital valves. Each of these exocrine gland components plays an important part in formation of the chemically complex pheromones utilized in the precopulatory behavior of the male.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 467-475 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The history of the germ cells is traced from the time of hatching. The germ cells are larger in size and have faintly staining cytoplasm, clear cell outline and a distinct nucleus. They migrate by ameboid movement to reach the genital ridge and aggregate to lie against the gonadal epithelium prior to the formation of gonads. The germ cells are distributed along the gonad primordia.The period of sex differentiation occurs between the 5.4 mm to 12 mm stage. The testis formation is recognized by the presence of germ cell nests and the sperm duct cord. The formation of the ovary is noted by the enlargement of the germ cells of uniform size and the development of the ovarian cavity.The ovaries are described in four stages ranging from 21 mm to 135 mm fish. At 21 mm stage the ovarian cavity is continuous but is obliterated at 35 mm stage due to the projection of the ovigerous lamellae. The common opening for both the ovaries develops at 35 mm stage. The testes are described in four stages ranging from 23 mm to 135 mm fish. They differentiate more slowly and the first maturation division is seen at 90 mm stage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 9-21 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Larvae of the subfamily Amphipteryginae (Odonata) bear a tuft of tracheal gills on either side of the anus. The two tufts are derived from the laminae sub-anales, and are protected by the non-respiratory epiproct and paraprocts, and by plates derived from the cerci, lamina supra-analis or the lamina sub-analis itself. Each is approximately 1 mm long in mature larvae and comprises a series of repeatedly branching filaments, the terminal twigs of which are 5 to 10 μ in diameter. The total surface area of the tufts is approximately 5.0 mm2 in mature larvae of Devadatta, and more in the larvae of Pentaphlebia and Rimanella. Each tuft is connected by a large trachea to the longitudinal tracheal trunk. This large trachea divides many times, eventually forming a dense palisade of tracheoles in the epidermis of the filaments, immediately beneath the thin investing cuticle.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The growth and morphogenesis of embryos of Aulocara elliotti (Thomas) at constant temperature are described in terms of 27 discrete morphological stages with four stages designating blastokinesis. The developmental variability of two series of embryos reared from a single wild population in two different years is compared. A bibliography to studies on other embryos of the Acrididae is included.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 391-396 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Giant salamanders, Amphiuma means, measuring 240 to 280 mm from snout to vent, tolerate induced anoxia for six hours. Most of the cardiac glycogen (beta units) is depleted within the first hour of anoxia but a few scattered units remain after six hours. The suggestion that cardiac glycogen is a stand-by energy source which enhances the energy available to the heart during anoxic strain is reasonable. Beta units are stored in the heart as opposed to the larger alpha units in the liver. The smaller beta units are probably more easily metabolized than the larger alpha units due to their greater surface area per volume ratio and dispersal around the numerous cardiac mitochondria.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 397-423 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Cytoplasmic microtubules and axial unit tubules were studied in both sectioned and negatively-stained material. Walls of microtubules of frog lung-fluke (Haematoloechus medioplexus) spermatozoa have a helical substructure, while those of the flagellate, Trypanosoma lewisi, are composed of ten longitudinally-oriented filaments. Cross-bridges occur between some filaments of trypanosome microtubules. Doublet tubules of axial units in both cell types are structurally similar to the trypanosome microtubules, which may indicate similarity of function. Microtubules of fluke spermatozoa appear to be somewhat rigid, are resistant to sonication, and are considered to be mainly supportive. Circular profiles of wall subunits are seen in transverse sections of microtubules of both cell types and in doublet tubules of the trypanosome. Comparisons are made between sectioned and negatively-stained material; while negative-staining better reveals the fundamental substructure of microtubular elements, some distortion appears to occur. In connection with this research, a brief preliminary article demonstrated the presence of subunits in the walls of cytoplasmic microtubules of fluke spermatozoa (Burton, '66). Also, it was shown that the wall of these tubular elements possesses a helical structure, and a diagrammatic representation of the wall structure was set forth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The infracerebral gland of Nereis is made up of three types of cells. C1 cells are hypertrophied pericapsular elements, whereas C2 and C3 cells have the morphological and cytological features of neurosecretory neurons. C2 and C3 cells give rise to centripetal “proximal processes” which extend into the brain through the midventral pocket formed by delamination of the brain capsule. Their “distal processes” terminate within the gland or its immediate vicinity. “Centrifugal fibers” arise from nerve cells located within the brain and appear to synapse upon the proximal processes of C2 cells in the region of the midventral pocket and in the ventral region of the brain. The cytology of C2 and C3 cells suggests that they are the source of distinct peptide hormones.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 321-326 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Exercise affects the growth of the dorsal longitudinal flight muscles in the tsetse fly. Examination of electron micrographs of flight muscles taken from flies subjected to enforced exercise, “ormal” exercise and no exercise reveals that both mitochondrial and myofibrillar fractions of the muscles are stimulated to grow at a faster rate by enforced exercise but that the mitochondria respond more rapidly.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Ultrastructure and shell formation in the testaceous ameba, Lesquereusia spiralis, were investigated with both scanning and transmission electron microscopy and X-ray microanalysis. The nucleus, surrounded by a fibrous lamina, contains multiple nucleoli. The cytoplasm, containing a well developed granular endoplasmic reticulum, also contains remnants of starch granules in stages of digestion. Spherical aggregates of ribosome-like particles may be seen. Golgi complexes seem to produce both a nonordered fibrous material and an electron dense vesicle. Only the latter appears to bleb off from the Golgi complex. X-ray microanalysis demonstration of silicon in Golgi vesicles and in some dense vesicles suggests that the fibrous component of the cisternae may take up and concentrate silica to form the electron-dense component of the vesicles. Membrane-bound siliceous crystals are often seen adjacent to the Golgi, suggesting either a Golgi origin or platelet formation in vesicles after release from the Golgi complex. Both electron-dense bodies and siliceous platelets are released from the cell by a process similar to apocrine secretion and may be seen outside the cell in route to the shell during shell morphogenesis. Shell development involves fusion of electron-dense bodies to form a matrix, positioning of siliceous platelets in this matrix parallel to the shell surface, and development of a system of matrix chambers. A particulate glycoconjugate is released to the shell surface upon rupture of the matrix chamber.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 359-368 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Stereological analysis of the ultrastructural composition of the pulmonary alveolo-capillary region of mice living at sea level compared with that of the same species (Phyllotis darwini) genetically adapted to life at 4,660 m reveals a trend at high altitude towards a greater volume percentage of tissue components. On a weight-specific basis, non-circulating tissue occupies a significantly greater volume in high-altitude mice, but air space and capillary contents are not correspondingly greater. Since the arithmetic mean thickness of the tissue layers and of the air-blood barrier are the same in the two altitudinal groups, the average alveolus must have a smaller volume in the high-altitude mice.Epithelial, endothelial, and erythrocyte surface areas per gram body weight are significantly greater in the high-altitude mice.Nuclear counts indicate that the larger lungs of mice adapted to high altitude are due to larger Pneumocyte I and II and endothelial cells rather than to an increase in the number of these cells. Hematocrits measured within the pulmonary capillaries in the two altitudinal groups were equal.An heretofore unrecognized feature of possible adaptive value is the surface/volume ratio of erythrocytes, which is similar for erythrocytes in alveolar space of mice at low and high altitudes but within lung capillaries is 14.7% greater at high altitude.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 299-305 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The neck region of the mature spermatozoon of Discus rotundatus is described. No evidence for a centriole or centriolar derivative is obtained. Nine striated coarse fibres and the two central fibres of the axoneme extend into the base of the implantation fossa. The axonemal doublet system is disrupted in the neck region. There are two fibrous accessory structures located between the central doublet and the striated coarse fibres.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 307-319 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Explants of 4.5-day-old chick embryonic neuroretinas with mesenchyme were exposed to Methotrexate (MTX) in medium 199 with embryo extract. Proliferative responses of the cultured neuroretinas were followed radioautographically by administration of 3H-thymidine to the cultures. The DNA synthetic, mitotic and pyknotic responses of the ventricular cells of the neuroretina were followed over a 16-hour period. The responses observed suggested that MTX caused a synchronization of the ventricular cells in the pre-mitotic phases with no direct inhibition of mitosis. Furthermore, prolonged exposure to MTX resulted in the accumulation of labeled pyknotic cells, indicating a decline in the regenerative capacity of the proliferative ventricular cells.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 369-397 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Successive tracheal cuticles of the dorsal longitudinal trunks are studied with the electron microscope. Minor differences seen at the light microscope level are seen as major qualitative and quantitative ones at the ultrastructural level. The larval and pupal cuticles are secreted by similar epithelial cells; these possess large polytene chromosomes. Cell division and possibly cell replacement occur prior to adult cuticle secretion. The findings are discussed in terms of cell specificity, intra- and inter-cellular pattern formation. This simple epithelium, the individual cells of which are capable of producing different cuticles, is interesting since the system is also shown to be responsive to hormone application.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 453-461 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Eggs of the common snapping turtle, Chelydra serpentina, were incubated at constant temperatures ranging from 20°C to 30°C, At hatching, the oviducts were absent or incomplete in males; the testes were differentiated. In females at hatching, the oviduct was intact hut in some cases the gonad retained bisexual characteristics. Three months after hatching, the ovary was differentiated and contained follicles. Eggs incubated at 20°C and at 30°C developed into females in 100% of the cases. At 26°C, 99% of the individuals were males; at 24°C, 100% were males. More males than females developed at incubation temperatures of 22°C and 28°C.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: New blastozooids of Polyzoa vesiculiphora, the polysytelid ascidian are produced by pallial budding of three types depending on the method of “isolated bud” formation; stolonic, planktonic and intermediate types. Differences among each type of bud are attributed to behavior of test-vessels composing a part of the bud. Isolated buds produced by each type are essentially equal in terms of their internal structures and their subsequent fate, and develop independently of their parent zooids. New test-vessels originate directly from the epidermis of a “prefunctional zooid,” while the test-vessels derived from the parent zooid finally disintegrate. The new test-vessels extended with branching under the ventral side of a “functional zooid,” ascend to the lateral side of it and participate in bud formation. Budding regions exist in three dimensions on the lateral wall of the mantle of the functional zooid, especially the right posterior part. During the life cycle of one functional zooid, the stolonic type buds appear at early and/or aged stages. Appearances of the stolonic type buds in early stages tend to repress those of the planktonic types. The number of planktonic type buds formed on a functional zooid at the same time is many more than that of the stolonic type. Such budding features are discussed from the viewpoint of behavior of the test-vessel system.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 337-353 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fine structural changes in mitochondrial morphology pertaining to size, number and growth were examined in flight muscles of normal and experimentally dewinged male Drosphila melanogaster ranging up to 26 days of age. In the normal winged flies, the number of mitochondria decreases during the first week of adult life whereas the size of individual mitochondrial profile increases significantly. Changes in mitochondrial size and number are due to the fusion of mitochondria. Fused mitochondria are extremely large in size and irregular in shape. In 26-day old normal flies, the number of mitochondria increases while the mitochondrial size is reduced indicating mitochondrial division. In comparison to the normal flies, dewinged flies exhibit a similar degree of mitochondrial fusion and growth during the first week of life. However, the extent of mitochondrial fission in 26-day old dewinged flies is greater than in the normal flies of this age. Structural mechanisms of mitochondrial fusion and fission are described. The objective of this study was to examine the relative effects of age and flight activity on the mitochondria.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 355-370 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The morphology of the abdominal defensive glands and associated structures of 115 species of tenebrionid beetles was studied on KOH cleared material. The glands and reservoirs of all Tenebrionidae are homologous and evolved as a pair of sacs from the intersegmental membrane between sternites VII and VIII. On the basis of reservoir morphology and secretory cell tubule termination, seven provisional gland types were established. Several of the types include species from several tribes, and several tribes contain several gland types, indicating possible incongruencies between the taxonomy and phylogeny of the family. Morphological trends in the evolution of the glands include: increase of reservoir capacity, constriction of the proximal portion of the sacs into distinct exit ducts, release of secretion by exuding or spraying rather than everting, and concentration of the secretory cell tubule terminations into restricted fields, collecting ducts or ampullae. The morphology of the glands of 58 species is illustrated and the results are discussed in light of the current taxonomy of the Tenebrionidae.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 371-385 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fine structure of the ion transporting epithelium of the neck organ in the brine shrimp (Artemia salina) nauplius is described. The neck organ is a dome-like gland situated atop the cephalothorax of the larva and is composed of 50 to 60 cuboidal epithelial cells. These cells possess many of the characteristics of salt-secretory cells from other tissues. They contain many mitochondria and exhibit a high degree of plasma membrane elaboration. This membrane amplification takes two forms; the apical plasmalemma is infolded into irregular loops, while the basal and lateral membranes penetrate the cytoplasm in the form of branching sinusoids. The labyrinth of tubular reticulum thus formed fills most of the cell volume. Mitochondria in the labyrinth are often in intimate contact with these tubular membranes and regular arrays of parallel mitochondria with constricted intervening sinusoids are often observed. Other organelles including Golgi complexes, multivesicular bodies, and rough endoplasmic reticulum are also numerous, particularly in the narrow rim of cytoplasm which lies between the apical infolds and the labyrinth. Yolk platelets and glycogen fields are conspicuous in the basal perinuclear regions of the cells.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The pulmonary veins of albino Wistar rats were studied by means of light and electron microscopy. The media of larger veins consists of cardiac muscle fibers which extend until the vessels attain about 100 μ in diameter. This coat consists of external longitudinal fibers and internal circular fibers. The vasa vasorum are well developed and the capillaries show pseudofenestrations. The numerous adrenergic and cholinergic nerve endings do not form typical motor end-plates as seen in skeletal muscles. The ultrastructure of these media muscle fibers is similar to that of rat hearts. The smooth muscle layer of larger pulmonary veins is not continuous as it is in smaller veins where it forms cushions. Comparisons of albino rats and other rodents reveal striking differences.Action potential shape and propagation velocity (0.5-1.2 m/s) along the myocardial coat of the pulmonary vein were similar to those observed in the left atrium and so was their sensitivity to locally applied acetylcholine. The physiological direction of propagation in rat pulmonary veins is toward the lung. This finding lends support to the hypothesis of a rhythmic, valve-like action of the striated musculature of the pulmonary venous wall during the systole and a possible role in the capacitance of the pulmonary circulation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 229-249 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The structure of the testis of Poecilia latipinna is described with particular reference to Sertoli cell-germ cell relationships during development and maturation of the germinal cyst. The cyst develops when primary spermatocytes become surrounded by a single layer of Sertoli cells at the testis periphery. As spermatogenesis and then spermiogenesis proceed, the cyst moves centrally in the testis toward the ducts comprising the vasa efferentia. In addition to being a structural part of the germinal cyst, the Sertoli cells phagocytize residual bodies cast off by developing spermatids and form an association with mature sperm, which resembles that observed in mammals, before the sperm are released into the vasa efferentia as a spermatozeugmata.The results of this investigation are discussed in view of what is known concerning testis structure in other teleosts and similarities between cell functions in teleosts and mammals. It is concluded that teleost Sertoli cells, teleost lobule boundary cells and mammalian Sertoli cells are homologous.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 215-227 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The dendritic patterns of cells in the optic tectum of the tegu lizard, Tupinambis nigropunctatus, were analyzed with the Ramon-Moliner modification of the Golgi-Cox technique. Cell types were compared with those described by other authors in the tectum of other reptiles; particular comparisons of our results were made with the description of cell types in the chameleon (Ramón, 1896), as the latter is the most complete analysis in the literature. The periventricular gray layers 3 and 5 consist primarily of two cell types  -  piriform or pyramidal shaped cells and horizontal cells. Cells in the medial portion of the tectum, in an area coextensive with the bilateral spinal projection zone, possess dendrites that extend across the midline. The latter cells have either fusiform or pyramidal shaped somas. The central white zone, layer 6, contains fibers, large fusiform or pyramidal shaped cells, fusiform cells, and small horizontal cells. The central gray zone, layer 7, is composed predominantly of fusiform cells which have dendrites extending to the superficial optic layers, large polygonal cells, and horizontal cells. The superficial gray and white layers, layers 8-13, contain polygonal, fusiform, stellate, and horizontal elements. Layer 14 is composed solely of afferent optic tract fibers.Several differences in the occurrence and distribution of cell types between the tegu and the other reptiles studied are noted. Additionally, the laminar distribution of retinal, tectotectal, telencephalic, and spinal projections in the tegutectum can be related to the distribution of cell types, and those cells which may be postsynaptic to specific inputs can be identified. The highly differentiated laminar structure of the reptilian optic tectum, both in regard to cell type and to afferent and efferent connections, may serve as a model for studying some functional properties of lamination common to cortical structures.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The antennae and their sense organs in nymphs and adult roaches of Gromphadorhina brunneri, were investigated and described. The number of segments and sensillae of the nymphal antennae depend on the developmental stage. Sexual dimorphism is pronounced. Males have longer antennae than females as well as an abundance of especially long sensory hairs (long wavy hairs), which are probably responsible for the perception of female sex pheromones. They also have more thin-walled sensory hairs, for instance, sensilla trichodea. On a morphological basis the sensillae of Gromphadorhina brunneri, were named and classified. Long wavy hairs and large sensory hairs appear to be present also in a related species, G. portentosa, but are lacking in others. Their distribution on the antennae varies greatly from that in G. portentosa but their structure varies only slightly. These two types of sense organs are considered to be specialized forms of sensilla chaetica. They are contact chemoreceptors, as are two other types of sensilla chaetica. Furthermore, thin-walled chemoreceptors are present, such as sensilla trichodea, sensilla basiconica, sensilla coeloconica and a typical mechanoreceptor, the sensillum campaniformium.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 265-306 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper describes the different regions of the Malpighian tubules and the associated structures (ampulla, midgut, ileum) in the cockroach, Periplaneta americana. There are about 150 tubules in each insect. Each tubule consists of at least three parts. The short distal region is thinner than the other parts and is highly contractile. The middle region comprises most of the tubule length and is composed of primary and stellate cells. Primary cells contain numerous refractile mineral concretions, while stellate cells have smaller nuclei, fewer organelles, simpler brush border, and numerous multivesicular bodies. Symbiont protozoa are sometimes present within the lumen of the middle region near where it opens into the proximal region of the tubule. The latter is a short region that drains the tubular fluid into one of the six ampullae. These are contractile diverticula of the intestine located at the midgut-hindgut junction. The ampulla is highly contractile, and consists of a layer of epithelial cells surrounding a cavity that opens into the gut via a narrow slit lined by cells of unusual morphology. The proximal region of the tubule and the ampulla resemble the midgut in that they have similar microvilli, basal infolds, and distribution of mitochondria. This suggests an endodermal origin and reabsorptive function for the proximal region of the tubule and for the ampulla. A number of inclusions found within the tubule cells are described, including peroxisomes and modified mitochondria. Current theories of fluid transport are evaluated with regard to physiological and morphological characteristics of Malpighian tubules. The possible role of long narrow channels such as those between microvilli and within basal folds is considered, as is the mechanism by which these structures are formed and maintained. Also discussed is the role of peroxisomes and symbionts in the excretory process.
    Zusätzliches Material: 39 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 307-323 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The fine structure of the intersegmental glands of the sixth abdominal sternum in 1-week old females of Nomia melanderi is presented. The plasma membrane of the secretory cell is unfolded in many places and is covered by a basement membrane. The microvillous surface is invaginated to form a rather long sinuous cavity. The endoplasm is almost entirely filled by secretory granules. Many secretory granules are located close to the inner surface of the invaginated plasma membrane. The invagination contains a porous ductule, apparently of cuticulin origin, that is connected directly with the inner layer of the transport duct of the duct-forming cell. This type of arrangement allows the direct flow of the secretory substance to the outside in a continuous way. The cylindrical duct-forming cell, besides having typical cell organelles, contains a cuticular transport duct. This duct is composed of a thin cuticulin layer surrounded by a rather thick epicuticular one. The results suggest that the secretory cell has two secretory cycles. The first occurs while the gland is differentiating (at the pupal stage) and is involved in secretion of the cuticulin that forms the porous ductule. The second cycle, which starts by the beginning of nesting, is involved in the secretion of a substance that is carried to the outside via the transport duct of the duct-forming cell.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Volumetric and histological changes of the central nervous system were studied during post embryonic development of a spider, Argiope aurantia.The neural mass of Argiope grows allometrically with respect to volume of the cephalothorax and body weight. In the first instar 46% of the cephalothoracic volume constitutes the neural mass and this is reduced to 4% in the female (9th stage) and 12% in the male (7th stage) spider.Growth curves for the cephalic ganglion, measured at all stages, represent a straight line. The neural mass of females is two and a half times larger than that of the males. The ganglion increased 24 fold in female and 10 fold in male spiders. Addition of neural mass occurs in all stages.The brain volume is greater than that of the subesophageal ganglion in the first two instars. In subsequent stadia, the subesophageal ganglion grows faster, and in females it is finally three times and in males two times larger than the brain.Growth of cortex and neuropile depict exponential curves. Comparison of growth patterns of these shows an inverse relationship during development. While the volume of the cortex is higher in the first two or three stages, the volume of the neuropile is higher in the remaining stadia. The causes for this growth pattern are discussed.Counts of cell numbers show that there is a constant population of neurons throughout the post-embryonic development. The number of nerve cells in females is higher than in males, 11% in the subesophageal ganglion and 58% in the brain.The growth of the cortex is partly accomplished by an increase in cell volume. In male and female spiders the increase in Type-B cells is 20 and 50 fold, while that of large motor neurons is 200 and 600 fold respectively. The motor neurons of 20 μ and above number 63 in male and 916 in female adult spiders.The growth of neuropile occurs through an increase of dendritic arborization and axonal branching. The largest axons measure 1 μ in the first and 16 μ in adult stages. An increase of incoming sensory fibers is also noticed during development.Invasion of neural lamella into cortex and neuropile increases during development. Neural lamella which are 1-2 μ in the first stage grow to 40-100 μ thickness in adult female spiders, near the origin of the main nerves. One type of astral cells, counted in neuropile, increases 10 fold.The appearance of a central body and the beginning of web construction coincide during the second instar. The relationship between these two is discussed.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 479-493 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Thirty-six harbor porpoises, Phocaena phocaena, were caught off the coast of Southern New Brunswick and Nova Scotia as part of a study of the biology and ecology of these animals. The formalin-preserved heart was examined first in situ, then measured and studied in detail. If the weight of the thick layer of blubber is discounted, the heart is heavy relative to the total body weight as may be expected in an animal capable of fast swimming, great agility and frequent emergence from the water to breathe. The shape of the heart, the relative size of atria and atrial appendages, the morphology of the ventricular septum, the thickness of the walls of the sinus and conus of the right ventricle and the anatomy of the pulmonary veins were found to be constant for this animal and unlike that of non-cetaceans. It is suggested that the absence of respiratory movements during diving may lead to these modifications of cardiac structure in an animal that is particularly well adapted to a totally aquatic existence.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 146 (1975), S. 533-542 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Rabbits are unique among mammals in that their ears can regenerate tissues from the margins of full thickness holes which grow in and completely fill the opening in about two months. The circular blastema that forms around the edges of the hole differentiates a new sheet of cartilage as it regenerates in a centripetal direction. Similar holes in other mammals fail to regenerate and form scar tissue instead of a blastema. Histological studies of the healing around the edges of rabbit ear holes reveal that during the second week, when the epidermis is completing its migration across the wound from the opposite sides of the ear, conspicuous tongues of epidermal cells grow down into the underlying tissues at the edges of the wound. These epidermal downgrowths are situated between the original intact dermis of the skin and the more central tissues which give rise to the blastema. Such downgrowths are of a transient nature, and are no longer found once the blastema rounds up toward the end of the second week. Since they are not found in the healing of similar wounds in rabbit ears prevented from regenerating by prior removal of their cartilaginous sheets, nor in the naturally nonregenerating ears of sheep and dogs, it is considered that these downgrowths of healing epidermis may play a role in the unusual regenerative response of ear tissues in the rabbit.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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