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  • Cell & Developmental Biology  (1,681)
  • 2020-2020
  • 1985-1989  (1,056)
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  • 1987  (1,056)
  • 1984  (625)
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  • 1985-1989  (1,056)
  • 1980-1984  (625)
  • 1970-1974
  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 179 (1984), S. 229-242 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Wild-collected adults of Bombina orientalis are bright green dorsally and red to red-orange ventrally. As a prelude to an analysis of the differentiation of pigment cells in developing B. orientalis, we describe structural and chemical aspects of the fully differentiated pigment pattern of the “normal” adult.Structurally, differences between dorsal green and ventral red skin are summarized as follows: (1) Dorsal green skin contains a “typical” dermal chromatophore unit comprised of melanophores, iridophores, and xanthophores. Red skin contains predominantly carotenoid-containing xanthophores (erythrophores), and skin from black spot areas contains only melanophores. (2) In ventral red skin, there is also a thin layer of deep-lying iridophores that presumably are not involved in the observed color pattern. (3) Xanthophores of red and green skin are morphologically distinguishable from each other. Dorsal skin xanthophores contain both pterinosomes and carotenoid vesicles; ventral skin xanthophores contain only carotenoid vesicles. Carotenoid vesicles in dorsal xanthophores are much larger but less electron dense than comparable structures in ventral xanthophores.The presence of carotenes in ventral skin accounts for the bright red-orange color of the belly of this frog. Similar pigments are also present in green skin, but in smaller quantities and in conjunction with both colored (yellow) and colorless pteridines. From spectral data obtained for xanthophore pigments and structural data obtained from the size and arrangement of reflecting platelets in the iridophore layer, we attempt to explain the phenomenon of observed green color in B. orientalis.
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  • 2
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 3
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 29-35 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study describes intercellular bridges in the ovaries of neonatal gerbils. Electron microscopy has revealed the presence of true intercellular bridges, connecting oogonia or oocytes, in ovaries of newborn gerbils. The cytoplasm of the intercellular channels is similar to that of the connected cells, with mitochondria, smooth and rough endoplasmic reticulum, and free ribosomes present. Lysosomes are also occasionally present in the intercellular bridges and they may be involved in early waves of oocyte atresia. An electrondense substance, 350-500 Å thick, is located immediately beneath the unit membrane of the intercellular bridges. Accumulation of electron-dense material increases the thickness of the walls of the intercellular bridges, supporting and maintaining the patency of the channels. It is suggested that the intercellular channels probably allow the interchange of nutrients, organelles, and possibly regulatory materials as well.
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  • 4
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 55-68 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A comparative study of the forelimbs of the semifossorial prairie dog, Cynomys gunnisoni, and the scansorial tree squirrel, Sciurus niger, was focused on the musculoskeletal design for digging in the former and climbing in the latter. Based on lever arm mechanics, it was expected that the forelimb of the prairie dog would show features appropriate to the production of relatively large forces and that of the fox squirrel to relatively great velocity. Force and lever arm measurements were made of select forelimb muscles at the shoulder, elbow, and wrist joints for a series of angles in both species. Contraction time and fatigue indexes were determined for the same forelimb muscles. Contrary to expectation, in the few cases in which significant (P 〈 .05) differences were found, the forces, lever arms, and torques (force times its lever arm) were greater in the smaller fox squirrel. The observed variation in the torques produced fits the demands on the forelimb during climbing and digging as estimated from films. Several forelimb muscles of the fox squirrel show significantly higher mean contraction times than do the homologous muscles of the prairie dog. There were no significant differences between the two species in the fatigability of the selected forelimb muscles, although the mean fatigue index was always higher (less fatigable muscle) in the prairie dog. Similarities in the forelimbs of these two sciurids suggest that only minor modifications may have been required of the ancestral forelimb in order for descendent forms to operate successfully as climbers and diggers.
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  • 5
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 105-124 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy of neurons of the stomatogastric nervous system of Ascheta domesticus was studied using heavy metal iontophoresis through cut nerve ends followed by silver intensification. Nineteen categories of neuron are described and compared with neurons known from the stomatogastric nervous system of other insects. Possible functions for the neurons are suggested. Motor neuron candidates are suggested for all parts of the gut served by the stomatogastric nervous system, and axons of sensory neurons of the anterior pharynx are located. There are four neuron types that cannot readily be assigned motor, sensory, or interneuron functions: large dorsal cells of the frontal ganglion; the two neurons of the nervus connectivus, and two categories of neurons in the median neurosecretory cell group of the pars intercerebralis, the axons of which are contained in the stomatogastric nerves.
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  • 6
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 159-169 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the pedicellar segment of the fly antenna there is a large campaniform sensillum. The central projection of the sensory cell (LCC) of this large campaniform sensillum is described from labeling with horseradish peroxidase (HRP) and cobalt. The LCC projects bilaterally to several regions of the brain and subesophageal and thoracic ganglia. The LCC processes in these termination areas were analyzed in relation to other neural processes, including the remaining antennal sensory and motor projection. This analysis was aided by combining HRP labeling with Golgi silver impregnation. Based on earlier findings and the present data we suggest that the LCC, with its various outputs in, e.g., antennal and leg motor centers, serves as a multifunctional sensory path involved in control functions necessary in flight.
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  • 7
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 8
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 173-180 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the long starvation period (November to June) of the lizard (Varanus exanthematicus), pancreatic B cells undergo profound modification. The degeneration of β granules observed in electron microscopy appears correlated with the diminution of the immunoreactive insulin-like content of the pancreas. The analogy between the phenomena observed here and those reported in animals treated with alloxan is discussed.
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  • 9
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 195-211 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and crystallography of the internal shell of the pulmonate gastropod slug Limax maximus were studied at the levels of light and scanning electron microscopy, revealing patterns of shell ontogeny and morphogenesis. The calcified portion of the slightly convex ovoid shell is composed of a single palisade layer of calcitic crystals. Numerous projections, 100 μm in width at the dorsal tip, are found on the dorsal surface of the shell and coincide with local nucleation sites of primordial calcium salt deposition onto the periostracum. With continued calcification these projections coalesce ventrally, forming the single crystalline shell layer. The organic portion of the shell includes the periostracum and an extensive PAS-staining conchiolin. In EDTA-etched preparations, conchiolin appears as a spongy network of fibers throughout the shell. Both horizontal and vertical components of the conchiolin are present, the former of variable thickness and occurring in an intercrystalline manner, the latter always occurring normal to the horizontal set. Macromorphogenic growth is characterized by three distinct temporal stages. Primary growth occurs radially from the umbonal region. Secondary growth is synonymous with shell thickening. Tertiary growth is characterized by both a lateral component, in which the shell extends beyond the primary growth boundaries, and a ventral component, in which the shell continues to grow in thickness. SEM of the ventral shell surface reveals a pattern of growth at the crystalmatrix interface. Proteinaceous fibers of the conchiolin occur unidirectionally in horizontal rows. Zones of incipient calcitic crystallization onto these hypostracal fiber bundles are contrasted by zones of increasing crystallization until the fibrous template (reduced hypostracum) is completely covered by crystals.
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  • 10
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 271-296 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electron microscopy shows that the pharyngeal lining of the larval lamprey Petromyzon marinus is a structurally complex epithelial system that can be separated into eight epithelial types: gill lamellar, gill interlamellar, goblet cell, protective, terminal (taste) bud, preciliated, ciliated in tracts, and ciliated in grooves. Furthermore, these epithelial types encompass at least sixteen different cell types based on ultrastructure and, in some cases, correlative histochemistry (PAS, Alcian blue). Common to nearly all the epithelial types are basal cells and intermediate cells. These two cell types are seen as undifferentiated. Among mature cells, structural specialization as proceeded in three directions: (1) elaboration of mitochondria, probably related to molecular transport (ion-uptake cells, chloride cells); (2) ciliogenesis (preciliated and ciliated cell types); and (3) production of mucous secretory granules (mucous-platelet cells, goblet cells, superficial protective cells, columnar mucous cells, “cobblestone” cells, and marginal and dark cells in the terminal buds). Many of the functions of the cell types relate to the process of suspension feeding in this animal.
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  • 11
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 243-252 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A small short muscle frequently acts across a joint in parallel with a vastly larger and longer muscle; therefore it should play a minimal role in the mechanical control of that joint. This study provides evidence suggesting that the small member of such a “parallel muscle combination” (PMC) may serve an important sensory feedback role. The spindle densities of large and small members of PMCs in man and the dog were determined and compared. Epaxial PMCs controlling canine intervertebral joints were dissected and tissue samples were embedded in paraffin, sectioned transversely to the muscles' long axis and, stained with hematoxylin-periodic acid-Schiff (PAS). Representative tissue sections were projected on to stereological grids and the percentage volume of spindles was determined. Data existing in the literature were used to ascertain spindle densities in human PMCs controlling joints in the cervico-occipital region and the extremities. The spindle density for each muscle in a group of PMCs controlling a particular motion was listed, and the mean spindle densities were determined for both the large and the small members of the group. Student's unpaired t test was used to determine the significance of the differences between mean spindle densities. Linear regression was calculated and the data were plotted graphically.In all PMCs examined, the spindle density of the small muscles was significantly higher than that of their large counterparts. It is therefore proposed that the small muscles of PMCs may function as “kinesiological monitors” generating important proprioceptive feedback to the central nervous system.
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  • 12
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 1-8 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The internal reproductive apparatus of female Platynotus punctatipennis is composed of the paired ovaries, paired lateral oviducts, common oviduct, spermatheca associated with its accessory gland, and a bursa copulatrix. The accessory (colleterial) glands are absent. The ovary is made up of a large number of telotrophic ovarioles which are covered by a double-layered peritoneal sheath. The terminal filament is separated from the germarium by the basement membrane of the latter and consists of a syncytial core surrounded by the peritoneal sheath. Nutritive cords are absent. The pedicel shows highly eosinophilic and PAS-positive secretion of obscure origin. The spermatheca reveals a number of interesting features. It is composed of a pair of sperm-storing tubules, enclosed in a very thin muscle layer. A winecup-like structure, provided with a thick coat of circular muscles, connects the spermathecal gland with thespermathecal duct. Four types of intimal linings occur in the spermatheca and its associated structures. The wine-cup-like connection and four types of intima are entirely new features observed. Histology of the various parts of the reproductive apparatus is described.
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  • 13
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 29-47 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The formation of somites, coelomic sacs, splanchnic mesoderm, fat bodies, circular system, gonads, and musculature in the embryo of the primitive moth, Neomicropteryx nipponensis Issiki, is described. The following paired somites are formed: the labral, antennal, intercalary, mandibular, maxillary, labial, three thoracic, and 11 abdominal. Small but distinct coelomic cavities appear in all these somites. Labral somites differentiate into the labral muscles, stomodaeal muscles, and dorsal dilator muscles of the pharynx. Antennal somites differentiate into the antennal muscles, aorta, and the ventral dilator muscles of the pharynx. Intercalary somites are short-lived, disintegrating to liberate many free cells into the yolk. The suboesophageal body is not formed. Mandibular somites differentiate into the mandibular flexor and extensor muscles. Maxillary and labial somites differentiate into the splanchnic mesoderm, fat bodies, and into muscles of the maxillolabial region. Three pairs of thoracic and ten pairs of abdominal somites split into the splanchric and somatic mesoderm. The 11th abdominal somites merge into the proctodaeal mesoderm, and differentiate into the musculature of the hindgut. The heart is formed by the fusion of the cardioblasts derived from the first thoracic to the tenth abdominal segment. The aorta arises from the antennal median mesoderm. Blood cells are derived from the median mesodermal cells of the maxillary to the tenth abdominal segment. Germ cells appear at the mediodorsal corner of each somite in the fifth abdominal segment. They become enclosed with a mesodermal sheath to form a pair of rudimentary gonads in this segment. Major muscles in the head, thorax, and abdomen of the fully grown embryo are described.
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  • 14
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 15
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    Journal of Morphology 181 (1984), S. 155-160 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The architectural and histochemical properties of the anatomically distinct compartments of the semitendinosus muscle (ST) of mice, rats, guinea pigs, and rabbits show that the ST is composed of two separate compartments aligned in series - a destal compartment (STd) and a proximal one (STp). The STp is further subdivided into a ventral head (STpv) and a dorsal head (STpd). The muscle fibers were arranged in parallel to the line of muscle pull within each compartment. The STd has the longest and the STpv the shortest fibers in all species. The physiological cross-sectional area and the estimated tetanic tension was greatest in the STd. Based on the staining pattern for myosin ATPase (alkaline preincubation) and an oxidative indicator (NADH or SDH), the STpv has the highest percentage of slow-oxidative (SO) or SO plus fast-oxidative-glycolytic (FOG) fibers of any portion of the muscle. The differences in fiber-type distributions and architectural designs of the separate compartments suggest a specialization of function of the individual compartments.
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  • 16
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 97-131 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The three-dimensional structure of the organ of Bellonci in the marine amphipod Gammarus setosus and the relationship between its sensory cells and concretion are described using light, transmission, and scanning electron microscopy, with chemical treatment for cell lysis, calcium chelation, glycogen staining, and lanthanum labelling. The organ is encapsulated and has three units called fuselli. Each is enclosed by two fusellar cells which generate and release calcium granule strands into the cores of the fusellar concretions, which are united in the center of the organ. The surface of each fusellus is traversed by spiral dendrites entering dorsally and ending ventrally. The spiral dendrites arise from sensory neurons contained in a palm-shaped ganglion in the center of the capsule, beyond which they are twisted like a rope before reaching the concretion. The spiral dendrites are linked in pairs by gap and tight junctions and each gives origin to two pairs of 9+0 sensory cilia 30 μm apart. The ciliary distal segments give rise to long tubules which are in contact with the calcium granule strands. The ciliary proximal segments are expanded by many long mitochondria which interdigitate with the branched striated ciliary rootlets. The concretion is suspended in the capsule cavity by axons originating from four neurons of a remote mechanoreceptor. The structure of the organ suggests that it is a sensory organ involved in the reception and integration of a variety of stimuli.
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  • 17
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the kidney and the bladder of the bullfrog (Rana catesbeiana), the bullfrog tadpole, and the mudpuppy (Necturus maculosus) were studied with special attention to the innervation of renal tubule cells and bladder epithelial cells. In the bullfrog kidney, nerve terminals and varicosities were frequently associated with the tubule cells, apparently in an increasing order from the proximal tubule to the connecting tubule. Although these terminals and varicosities did not directly contact the tubular cell membrane, an aggregation of synaptic vesicles on the side facing the tubule was considered as morphological evidence that neurotransmitter can be released here and can affect the transport activity of the tubule cells. The association of nerve varicosities with canaliculi cells in the connecting tubule was also demonstrated. In the bullfrog tadpoles, renal tubule cells were occasionally innervated. In the mudpuppy, renal tubule cells were only poorly innervated. The epithelium of the bullfrog bladder was commonly innervated. Nerve terminals with synaptic vesicles were located very near basal cells and even contacted them directly on rare occasions. In the mudpuppy, the innervation of the bladder epithelium was observed infrequently. The bullfrog tadpoles did not possess an apparent bladder. In all materials studied, renal arterioles and bladder smooth muscle cells were innervated.
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  • 18
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 19
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    Journal of Morphology 191 (1987), S. 17-23 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous studies have examined the isometric contraction properties of the two heads of the cat flexor carpi ulnaris acting as a single unit. In this study, the contraction properties and fiber architecture of each head of the flexor carpi ulnaris were determined separately and related to previous reports on the histochemical characteristics of this muscle. The morphology of retrograde-labeled motor nuclei for the two heads of the muscle was also examined. The humeral head had a significantly longer contraction time (48 msec) than the ulnar head (36 msec) as well as a significantly lower tetanic fusion frequency (28 Hz vs. 35 Hz). The maximum tetanic tension per gram of muscle tissue was 71% greater in the ulnar head. Motoneurons of the flexor carpi ulnaris formed a column 12 mm long and 0.5 mm wide in the center of the ventral grey in spinal segments C8 and T1. The ulnar head had α-motoneurons with greater soma diameters than those in the humeral head. The smaller soma diameter, slower contraction time, and weaker contraction in the humeral head correlate with the preponderance of oxidative-metabolic muscle fiber types found in the humeral head by other workers. These correlations suggest that the humeral head plays a major role in maintaining a sustained antigravity tension that prevents the wrist from buckling during standing.
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  • 20
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Comparison of metamorphosis of skull and hyobranchial system in two species of neotenic salamanders reveals two different types of neoteny. Ambystoma talpoideum is completely neotenic owing to delayed metamorphosis. Notophthalmus viridescens exhibits limited neoteny as a result of incomplete metamorphosis. Morphological details of neoteny are compared to life history in both species in order to discuss the ecological morphology of the two neotenic strategies. Comparisons to Taricha granulosa, Triturus vulgaris, and Ambystoma gracile indicate that these two strategies are widely employed and may represent familial patterns.
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  • 21
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    Journal of Morphology 191 (1987), S. 247-263 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using scanning electron microscopy I determined neuromast number and orientation, neuromast sensory epithelial surface area and relative position, hair cell number per neuromast, hair cell size, and stitch formation in aquatic urodeles. All aquatic salamanders examined (34 specimens, 20 species, 16 genera, nine families) had neuromasts. The basic pattern of neuromast organization was similar in all species, consisting of a single row of circumorbital (supraorbital + infraorbital) neuromasts and anteriorly along the snout two rows of nasal and three rows of maxillary neuromasts. Nasal and maxillary groups consisted of orthogonally oriented neuromasts. Variation in most parameters occured at every taxonomic level, between individuals of the same species, and even on opposite sides of the same individual. Among species, primary neuromast number ranged from 94 to 150, with plethodontids having higher numbers. Despite high intraspecific variation, neuromast number fell into a sufficiently narrow range to be useful systematically. Hair cell number per neuromast was greater in species with larger animals. Hair cell number per neuromast and number of primary neuromasts did not increase with growth. In some species primary neuromasts divided to form secondary neuromasts (together termed a stitch). Two types of stitches-transverse and longitudinal-were formed. Transverse stitches were characteristic of ambystomatids and cryptobranchids, longitudinal stitches were characteristic of proteids and salamandrids. Because transverse stitches are also characteristic of anurans, this trait may be the generalized condition in at least these two amphibian orders. With stitch formation total number of hair cells on the dorsal surface of the head of these animals can be increased over tenfold to almost 20,000. Ecologically, lentic forms tended to form transverse stitches, while lotic forms had single neuromasts in epidermal pits or longitudinal stitches in epidermal grooves. Lotic forms also tended to have more primary neuromasts and more nasal and maxillary neuromasts.
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  • 22
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    Journal of Morphology 193 (1987), S. 23-33 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The labral glands of Daphnia consist of three distinct functional units on each side: (1) several cells at the base of the head, (2) two large cells at the base of the labrum and one large cell (cell A) in the median part of the labrum and (3) one large cell (cell B) in the median part of the labrum. These gland cells do not form a syncytium, contrary to reports by previous investigators. With the exception of cell B, they have a well-developed rough endoplasmic reticulum and many active Golgi complexes. The Golgi activity changes during the molt cycle. The Golgi activity of the cells of the head base is different from that of the large cells of the labrum. Since clear exocytotic phenomena were not observed, the secretion can be assumed to flow into the hemolymph after accumulation in the enlarged intercellular spaces. Cell B has a distinctive cytoplasmic ultrastructure the function of which is not yet understood.The four large cells of the labrum are in contact with a duct cell (or several duct cells) characterized by a deep infolding of the plasma membrane. This delimits a narrow lumen, which contains no secretion. No passage of substance is visible from the gland cells to the duct cell(s).
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  • 23
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    Journal of Morphology 193 (1987), S. 63-73 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The adrenergic innervation of structures in the gills of six teleost species was studied with catecholamine fluorescence histochemistry. The species studied were the following: sand flathead, Platycephalus bassensis and blue-spot flathead Platycephalus caeuruleopunctatus (Platycephalidae); smooth toadfish, Tetractenos glaber (Tetraodontidae); Australian short-finned eel, Anguilla australis (Anguillidae); river blackfish, Gadopsis marmoratus (Gadopsidae); and common carp Cyprinus carpio (Cyprinidae).In all species except C. carpio fluorescent components were observed in the branchial nerves in the gill arch.In the arterio-arterial vascular pathway, the afferent and efferent branchial arteries were innervated only in Cyprinus. Fluorescent nerve fibres were found on afferent filamental arteries of all species except A. australis and on many afferent lamellar arterioles of all species except T. glaber. The secondary lamellae were devoid of fluorescent nerve fibres in all species. In Cyprinus and Anguilla, fluorescent nerve fibres were observed on occasional efferent lamellar arterioles. In Cyprinus, there was an additional innervation on the basal one-third of the efferent filamental artery. The innervation of the arteriovenous vascular pathway was similar in all species. Fluorescent nerve fibres were found on nutritive arterioles, and in the core of each filament between the surface epithelium and the wall of the filament venous sinus.Since most of the adrenergic innervation was found on afferent vessels of the arterio-arterial pathway, it is suggested that adrenergic nerves and circulating catecholamines may have distinct functions in the regulation of blood flow through the gills.
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  • 24
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    Journal of Morphology 193 (1987), S. 117-133 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gross dissection, light microscopy, and transmission electron microscopy were used to generate a detailed understanding of the ovarian anatomy of the pipefish, Syngnathus scovelli. The ovary is a cylindrical tube bounded by an outer layer consisting of a smooth muscle wall and an inner layer of luminal epithelium, with follicles sandwiched between the two layers. A remarkable feature of this ovary is a sequential pattern of follicle development. This pattern begins at the germinal ridge with a gradient of follicles of increasing developmental age extending to the mature edge. The germinal ridge is an outpocketed region of the luminal epithelium containing early germinal cells and somatic prefollicular cells. Therefore, the germinal ridge and luminal epithelium share the same ovarian compartment and follicle formation occurs within this compartment. The mature edge is defined as the site of oocyte maturation and ovulation. The outer ovarian wall contains unmyelinated nerve fibers throughout. Longitudinally oriented unmyelinated nerves are also observed near the smooth muscle bundles associated with the mature edge. Oocytes near the mature edge are polarized such that the germinal vesicle (nucleus) is generally oriented toward the luminal epithelium. The sandwichlike organization of the ovary results in follicles that have a shared theca. An extensive lymphatic network is also interspersed among the follicles. Thus, the exceptional features of the pipefish ovary make it particularly well suited for the examination of early events in oogenesis. Specifically, we characterize pipefish folliculogenesis in detail.
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  • 25
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    Journal of Morphology 193 (1987), S. 185-196 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The hemocytes of Leiobunum limbatum, Mitopus morio, and Opilio ravennae number from about 8,000 (juveniles) to 41,000 (pregnant females) per microliter of hemolymph. Five different types of hemocytes occur in all three species and both sexes. According to their ultrastructural appearance and their similarities to other arthropod hemocytes these five types are designated as prohemocyte, plasmatocyte, granulocyte, coagulocyte, and spherulocyte. From the ultrastructural point of view the prohemocytes are interpreted as stem cells for plasmatocytes which on their part differentiate into granulocytes. Transitional stages which would indicate the origin of coagulocytes and spherulocytes could not be found.Granulocytes and spherulocytes are interpreted as being storage cells; coagulocytes burst when hemolymph is transferred to a microscopic slide. Plasmatocytes are involved in the removal of dead cells or cell fragments. Plasmatocytes are demonstrated as being able to phagocytize and digest bacteria.
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  • 26
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    Journal of Morphology 193 (1987), S. 225-239 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Pituitary glands of adult male lizards (Anolis carolinensis) were studied in an effort to monitor seasonal cytologic changes quantitatively. Cells were identified immunocytochemically and on the basis of ultrastructural characteristics.Electron micrographs of the anterior pars distalis (containing lactotropes, corticotropes, and gonadotropes) of lizards collected in spring and fall were analyzed morphometrically. Lactotropes are the most numerous cell type in this area and occupy the largest volume. They are closely followed by corticotropes. Neither kind of cell undergoes a marked seasonal change in number or size or in the percent of the analyzed volume they occupy. Morphometric and ultrastructural criteria indicate an increased level of activity in all three kinds of secretory cells in the spring, although changes are relatively modest in corticotropes and lactotropes.Gonadotropes occupy less than half the volume of either of the other secretory cells in the analyzed area, but undergo considerable seasonal modification. They are larger (〉 40%) and more numerous (20%) in the spring, and show an increase in biosynthetic organelles at this time. Although the density of secretion granules may be reduced in the enlarged spring gonadotropes, the number of granules per cell may not be altered seasonally.Seasonal changes in the three cell types analyzed are moderate in contrast to the cytologic modifications described in pituitary cells following castration or other experimental procedures. Necrotic cells appear to be a normal component of the pituitary gland of Anolis carolinensis throughout the year.
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  • 27
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    Journal of Morphology 192 (1987), S. 205-215 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Septate junctions develop initially just basad from apical junctional complexes at the apical ends of regenerating gastrodermal cells. The first morphological indication of differentiation of the junction is the appearance of gentle undulations of the plasma membranes of apposing cells. Subsequently dense dots develop at fairly regular intervals at the cytoplasmic surface of one cell, while SER cisternae become localized opposite them near the surface of the apposing cell. The dense dots are associated with bulges which narrow the intercellular space. Later the dense dots are replaced by filaments aligned along the inner leaflet of the parent cell. Strands of amorphous deposits form connections between SER cisternae and the sister membrane on the opposite side of the junction. Ruthenium red staining provides information on precursors which occupy the intercellular space between the apposed plasma membranes. As development of the junction progresses, ruthenium red stains only the newly formed septa but not the interseptal matrix. Regular arrangement of individual septa seems to be completed under the control of V-projections from both of their surfaces. Precursors for the structural material of the septa may be a secretory product derived from the SER. Dense dots and their derived filaments probably serve as reinforcing material for strengthening the cell membrane of the junction.
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  • 28
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    Journal of Morphology 192 (1987), S. 237-246 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Freshly extruded and hardened spermatophores of the spiny lobster, Panulirus interruptus, were compared using light and electron microscopy (EM). The spermatophore is composed of a sperm tube embedded in an acellular matrix. The sperm tube consists of tightly packed spherical cavities in an acellular material within which the sperm lie. The extruded spermatophore is white, soft, and sticky on all surfaces. The highly coiled sperm tube can be seen near the surface of the foot of the spermatophore, which is the side that will attach to the exoskeleton of the female. The opposite surface, the cap, will harden and darken after exposure to seawater. In the soft spermatophore, the matrix surrounding the sperm tube and extending from foot to cap is composed of small (2-μm) granules embedded in a loose weave of filaments. In the hardened spermatophore, the matrix is composed of small (4-μm) empty spheres. At the cap region the matrix darkens, and at the foot the granules dissolve to form a thick layer characterized by vertical striations. The structure of this spermatophore is compared to those spermatophores of other decapods that have been described at the EM level. The chemical composition and possible function(s) of the various components are discussed.
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  • 29
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    Journal of Morphology 193 (1987), S. 35-51 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light and electron microscopy reveal that simple receptor cells in the jaw epithelium of sea urchin pedicellariae are connected by nerve tracts to the neuropile that coordinates jaw movements. The muscles responsible for jaw opening and closure and for flexion of the stem are all innervated in this neuropile. At least two types of vesicles occur at the simple synapses between neurone profiles and at neuromuscular junctions. The muscles include both striated and smooth fibres; however, their distribution varies according to pedicellaria type, and an unexpected arrangement exists in trifoliate pedicellariae.
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  • 30
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    Journal of Morphology 193 (1987), S. 75-89 
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    Notes: In the whip spider Heterophrynus elaphus the first pair of legs is specialized to serve sensory functions. The morphology of these “whips” and the sensory organs of their tarsi and tibiae are described using scanning and transmission electron microscopy. The tarsus is normally subdivided into 74 segments and bears 7 types of sensory hairs: bristles, club sensilla, two types of porous sensilla, two types of rod sensilla, and leaflike hairs. In addition there are modified claws, 3 kinds of slit sense organs, a “pit organ,” a “plate organ,” and probably a joint receptor. The tibia is usually subdivided into 33 segments. In addition to bristles the tibia bears 7 trichobothria at constant locations and a lyriform slit sense organ. The functional and systematic implications of these findings are discussed.
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  • 31
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    Journal of Morphology 193 (1987), S. 99-116 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Vernalized gemmules of the marine sponge Haliclona loosanoffi were cultured at 20°C, fixed at 24-hour intervals (0-11 days), and processed for light microscopy by using a variety of absorption and fluorescent staining methods. The cytochemistry and morphology of development were compared to the well-studied developmental patterns of freshwater sponges and to the patterns described in the marine sponge Suberites domuncula. The precocious development of H. loosanoffi gemmules involves early morphogenesis occurring within the unhatched gemmule, as opposed to the patterns in freshwater sponges, where most development occurs after the gemmule hatches. Definitive sponge tissue surrounding a single osculum is present 9 days after release from dormancy.
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  • 32
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    Journal of Morphology 191 (1987), S. 1-15 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cat hindlimb contains several long, biarticular strap muscles composed of parallel muscle fascicles that attach to short tendons. Three of these muscles -sartorius, tenuissimus, and semitendinosus -were studied by dissecting individual gold-stained fibers and determining the surface distribution of acetylcholinesterase-stained end-plate zones. In each muscle, fascicles were composed of muscle fibers that ran only part of the fascicle length and tapered to end as fine strands that interdigitated with other tapering fibers within the muscle mass. Most muscle fibers measured 2-3 cm in length. Fascicles of muscle fibers were crossed by short transverse bands of endplates (1 mm wide by 1-5 mm long) that were spaced at fairly regular intervals from the origin to the insertion of the muscle. The endplate pattern suggested that the fiber fascicles were organized into multiple longitudinal strips. In the sartorius, the temporospatial distribution of electromyographic (EMG) activity evoked by stimulating fine, longitudinal branches of the parent nerve confirmed that each strip was selectively innervated by a small subset of the motor axons. These axons appeared to distribute their endings throughout the entire length of the fascicles, providing for synchronous activation of their in-series fibers.
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  • 33
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    Journal of Morphology 191 (1987), S. 49-62 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper offers a model for the normalized length-tension relation of a muscle fiber based upon sarcomere design. Comparison with measurements published by Gordon et al. (′66) shows an accurate fit as long as the inhomogeneity of sarcomere length in a single muscle fiber is taken into account. Sequential change of filament length and the length of the cross-bridge-free zone leads the model to suggest that most vertebrate sarcomeres tested match the condition of optimal construction for the output of mechanical energy over a full sarcomere contraction movement. Joint optimization of all three morphometric parameters suggests that a slightly better (0.3%) design is theoretically possible. However, this theoretical sarcomere, optimally designed for the conversion of energy, has a low normalized contraction velocity; it provides a poorer match to the combined functional demands of high energy output and high contraction velocity than the real sarcomeres of vertebrates.The sarcomeres in fish myotomes appear to be built suboptimally for isometric contraction, but built optimally for that shortening velocity generating maximum power. During swimming, these muscles do indeed contract concentrically only. The sarcomeres of insect asynchronous flight muscles contract only slightly. They are not built optimally for maximum output of energy across the full range of contraction encountered in vertebrate sarcomeres, but are built almost optimally for the contraction range that they do in fact employ.
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  • 34
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    Journal of Morphology 191 (1987), S. 77-87 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Development and innervation of the lymph heart musculature of chicken, emu, rhea, and duck was studied by electron microscopy at posthatch ages from 3 days to adulthood. Development of innervation was monitored by acetylcholinesterase staining. Horseradish peroxidase was used to determine the extent of the transverse tubule network. Chickens were unusual among these birds in that lymph heart myocytes had already undergone a definitive differentiation and degeneration by 3 days. In ducks and ratite birds, lymph heart myocytes more slowly but progressively differentiate a cytomorphology that does not conform in all characteristics to cardiac or skeletal muscle and even resembles in some aspects, smooth muscle. Myofibrils become the dominant cytoplasmic structure, transverse tubules form ‘internal couplings’ with agranular reticulum cisternae, and ‘external couplings’ are formed between myocytes at myomyal junctions. The myomyal junctions also contain AChE-positive reaction product and some subplasmalemmal vesicles that lack a dense core. The lymph heart myocardium of ducks of 2 weeks demonstrated mitotic figures. In adult ducks the myosatellite cell numbers diminish and a characteristic pattern of myocyte degeneration appears. In juvenile ducks and ratites some myocytes differentiate to conductile cells, much as the conductile myocytes and myofibers of the blood heart. The lymph heart innervation is described, and the role of nerve in differentiation and maintenance of myocyte morphology in the lymph heart is discussed.
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  • 35
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    Journal of Morphology 191 (1987), S. 145-149 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron micrographs of microcorrosion casts of the renal vascular system of Pseudemys scripta and Testudo hermanni show fairly well-developed, round glomeruli in the former (mean diameter of casts: 83.1 μm) and fewer but bigger, ovoid glomeruli (mean diameter of casts: 111.1 μm/131.6 μm) in the more arid-adapted. T. hermanni. Furthermore, the intrarenal development of the pertiubular capillary system differs in these two species. These relatively minor morphological differences correlate well with the major differences in the ecology of these species, as well as with physiological data on urine composition from the literature.
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  • 36
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    Journal of Morphology 194 (1987), S. 41-53 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The prominent accessory lobes of Lachi in birds are considered to be marginal nuclei; similar nuclei have been implicated in mechanoreceptive functions in snakes and lampreys. Reptile studies emphasized the involvement of the denticulate ligament with this mechanoreceptive function. This investigation examines the fine structure of the accessory lobes of Lachi in pigeons and their interaction with ligaments for features which might support such a mechanoreceptive function. In the lumbosacral area of the spinal cord, the lateral longitudinal ligaments and the ventral longitudinal ligament are hypertrophied. The ventral transverse ligaments are present only within the lumbosacral segments of the spinal cord and they interconnect with the lateral and ventral longitudinal ligaments. The lateral longitudinal ligament makes intimate contact with the spinal cord, and many glial processes from the spinal cord mingle with and are firmly attached to collagenous fibers of the ligament. The lobes lie dorsal to the lateral longitudinal ligament in the exact area where it interconnects with the transverse ligament. The lobe's multipolar neurons have a number of synaptic contacts but no unusual specializations were noted. Most of each lobe is composed of interdigitating saccular structures filled to varying degrees with flocculent material. The sacs are extensions of the cytoplasm of neuroglial cells, which also give rise to membranes surrounding neuronal processes and the sacs themselves. A possible functional relationship of the lobes and the ligaments of the lumbosacral spinal segments within the vertebral column is described.
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  • 37
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    Journal of Morphology 194 (1987), S. 75-84 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Several morphological and functional characteristics of the rat gastrocnemius medialis and tibialis anterior muscle were studied in young, adult, and old rats to assess the influence of growth. Antagonist muscles were studied to determine how changes of muscle architecture and functional characteristics are influenced by the demands of increased body weight and by the specific roles of these muscles in locomotion.Both muscles change drastically, for instance, in muscle length, volume, physiological cross-sectional area aponeurosis length, and their muscular geometry changes allometrically for both muscles. The relationships between muscle length, distance between origin and insertion, tendon length, and tibial length also change with growth. Both muscles are rather pennate, so that the increase of physiological cross-sectional area is a major factor in the determination of muscle length.No significant difference could be shown for fundamental physiological characteristics (i.e., functional characteristics normalized for muscular dimensions such as maximal work per unit volume). The changes of morphological and functional variables of both muscles parallel each other as is apparent from the index of antagonist characteristics, which is constant for all variables studied with the exception of muscle volume and tendon length.Consequently, the considerable and similar changes of TA and GM morphology and functional characteristics that take place during growth from approximately four weeks postnatally is not caused by changes of muscular material but by changes of the amount and architectural arrangement of the material involved.
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  • 38
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    Journal of Morphology 194 (1987), S. 143-161 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Between weaning and adulthood, the length and height of the facial skull of the New Zealand rabbit (Oryctolagus cuniculus) double, whereas much less growth occurs in the width of the face and in the neurocranium. There is a five-fold increase in mass of the masticatory muscles, caused mainly by growth in cross-sectional area. The share of the superficial masseter in the total mass increases at the cost of the jaw openers. There are changes in the direction of the working lines of a few muscles. A 3-dimensional mechanical model was used to predict bite forces at different mandibular positions. It shows that young rabbits are able to generate large bite forces at a wider range of mandibular positions than adults and that the forces are directed more vertically. In young and adult animals, the masticatory muscles differ from each other with respect to the degree of gape at which optimum sarcomere length is reached. Consequently, bite force can be maintained over a range of gapes, larger than predicted on basis of individual length - tension curves. Despite the considerable changes in skull shape and concurrent changes in the jaw muscles, the direction of the resultant force of the closing muscles and its mechanical advantage remain stable during growth. Observed phenomena suggest that during development the possibilities for generation of large bite forces are increased at the cost of a restriction of the range of jaw excursion.
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  • 39
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    Journal of Morphology 194 (1987), S. 195-207 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The exocrine glandular system of the nymphs and the adults of Dysdercus cingulatus were studied. The D. cingulatus nymphs present 3 dorso-abdominal glands (lying under the 3rd, 4th, and 5th abdominal terga) and a pair of dorso-lateral pygidial glands on the pygidium (tergum 8). Histological and ultrastructural studies show that the upper and lower walls of the dorso-abdominal glands differ in structure; 3 types of cells were described: epidermal cells, unicellular secretory cells, and multicellular secretory units. Each of these exocrine glands plays an important part in the behavior of the nymphs (gregariousness, alarm, defense). The morphology of the various glands is discussed, and the chemistry of their secretions and their biological functions are considered.
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  • 40
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    Journal of Morphology 179 (1984) 
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  • 41
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    Journal of Morphology 179 (1984), S. 13-19 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic microtubules can be divided into two subpopulations: (1) those adjacent to the nucleus (perinuclear), and (2) those distributed between the myofilament bundles (nonperinuclear). Previous observations (Cartwright and Goldstein, '83) indicate total cytoplasmic microtubule numeric density increases to a maximum at 5-9 days and decreases to the steady value of the adult muscle. We have examined the numeric density (mean numbers of microtubule profiles per μm2 cross-sectional area) of the perinuclear subpopulation and compared it to the numeric density of the total cytoplasmic microtubule population in postnatally developing rat papillary muscle ages 1, 3, 5, 9, 21, and 42 days, and adult. The perinuclear region was defined as the area around the nucleus which extends to the 0.273 μm from the nuclear envelope. The density of perinuclear microtubules did not change with postnatal development. Our study suggests that perinuclear microtubules are a separate and relatively stable subpopulation of the total population of cytoplasmic microtubules and may serve a function different from that of the more variable nonperinuclear microtubules.
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  • 42
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    Journal of Morphology 180 (1984), S. 19-28 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Each antenna of both sexes of adult Rhodnius prolixus has approximately 570 mechanosensitive neurons that innervate five morphologic types of cuticular mechanosensilla: campaniform sensilla, tapered hairs, trichobothria, and type I and type II bristle sensilla. Each campaniform sensillum and tapered hair is presumably innervated by one mechanosensitive bipolar neuron and probably functions in proprioception. The campaniform sensilla being located at the base of the scape could monitor the position of the antenna. Tapered hairs are found at the distal margin of flagellar segment I and projecting laterally from the bases of the pedicel and scape. They probably provide information about the relative positions of the antennal segments. Seven trichobothrium are located on the pedicel and three on flagellar segment I. Each trichobothrium has a long filamentous hair inserted into the base of a socket that extends inwardly as a cuticular tube and is innervated by one bipolar neuron with a tublar body, a parallel arrangement of microtubules associated with electron-dense material. The trichobothria may respond to small variations in air currents.Type I bristles occur at the base of the antenna and are the most numerous type of mechanosensillum; an average of 452 occur on each antenna of females and 440 on males. The bristle is curved toward the antennal shaft and is serrated distally. Type II bristles are located distally and are the second most numerous type of mechanosensillum; an average of 88 were counted on each antenna of females and 94 on males. The type II bristle is straight with small, longitudinal, external grooves and projects laterally from the antennal shaft. Each type I and II bristle sensillum is innervated by a bipolar neuron whose dendrite is divided into an inner and outer segment. The outer segment is encased by a dendritic sheath which may be highly convoluted and distally contains a tubular body. Two sheath cells are associated with each sensillum. Both types of bristle sensilla have a tactile function.The tubular bodies of both types of bristle sensilla have a complex structure indicating that they are very sensitive. Variations in the amount and arrangement of the electron-dense material at the tip of the tubular bodies may reflect differences in viscoelastic properties that underlie functional characteristics.
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  • 43
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    Journal of Morphology 180 (1984), S. 69-79 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fine structural study indicates that the neuromuscular system of stage I polyps of Aurelia aurita is exclusively ectodermal.The three major muscle fields are the radial muscles of the oral disc, the longitudinal muscles of the tentacles, and the muscle cords of the septae and the column; the muscle fields are in physical continuity at the peristomial pits and share a common innervation and type of myofibril. The myofibril is striated in the tentacle base, in the outer oral disc, and in the upper part of the muscle cord; it grades into a smooth muscle toward the tentacle tip, the mouth, and the lower part of the cord. There is a fourth field of longitudinal smooth muscle in the pharynx.The nervous system consists of an epithelial sensory cell in the tentacle and a single type of neuron found in the subepithelial layer of the tentacle, oral disc, and muscle cord. The lack of gap junctions suggests that there is no nonnervous conduction system. The subepithelial layer also contains three types of fibers and a type of soma which cannot be characterized as neuronal. The soma is identified as the “neurosecretory cell” described in Chrysaora. The absence of neuromuscular elements in the column and stolon distinguishes the Aurelia aurita collected from Washington, USA, from English polyps previously described.
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  • 44
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    Journal of Morphology 180 (1984), S. 125-144 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and interrelationships of the mouthparts and of the food canal and its accessory cephalic structures of the females of Simulium venustum are described through microscopic observations. The mouthparts that enter the would during feeding are the mandibles, maxillary laciniae, hypopharynx, and labrum and collectively form a “syntrophium.” The labium and labellar lobes, which do not enter the wound, ensheathe the syntrophium distally and must be retracted to allow biting.We present an interpretation of mouthpart function during biting that emphasizes how biting steps are accomplished and what sensory structures are used to monitor the process. Four phases of biting are identified: (1) initial penetration of the skin effected by the mandibles; (2) consolidation of mouthpart position involving anchoring the syntrophium into the wound by means of the barbed laciniae; (3) diet sampling and active feeding - food (blood) is pumped by three groups of muscles forming two functional pumps, one located in the cibarium, the other in the pharynx. These pumps are separated from each other and from surrounding regions of the food canal by valve muscles making the pumping process a complex and highly coordinated series of muscular contractions; and (4) mouthpart disengagement involving removal of the laciniae, thus releasing the syntrophium from the wound.
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  • 45
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    Journal of Morphology 180 (1984), S. 37-54 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The external morphology of contact-chemoreceptive hairs (taste hairs) of six fly species, Calliphora vicina, Lucilia caesar, Musca domestica, Phormia terranovae, Sarcophaga carnaria and Stomoxys calcitrans, is described. The species can be distinguished by the differences between the patterns of taste hairs at the ventral side of their prothoracic tarsi. Taste hairs can be subdivided into morphological types, using the shape of the cuticle around the apical pore as criterion, even though this shape changes slightly on opening and closing of the pore. Light microscopical studies reveal that the nature and osmolarity of stimuli are decisive for the effect stimuli have on the shape of the top of the labellar hairs. The motions of the apical cuticle appear to be reversible.Gentle ultrasonic treatment preserves the shape of the cuticle of the top and the diameter of the pores on fluid stimulation. This technique makes it possible to study the effect of a previous stimulation on both tarsal and labellar hairs with the scanning electron microscope. It is supposed that stimuli can affect cuticular components around the pore, producing volume changes in that cuticle which alter the diameter of the pore.
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  • 46
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    Journal of Morphology 180 (1984) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 47
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    Journal of Morphology 180 (1984), S. 297-308 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the breeding season, male anurans display clasping behavior by holding females with their forelimbs. This behavior is peculiar to males, and may require specializations in forelimb musculature. The present study revealed that five kinds of forelimb muscles were heavier in the male Japanese toad than in the female: the flexor carpi radialis (FCR), the flexor antibrachii medialis caput superius (FAMsup), the abductor indicis longus (AIL), the extensor carpi radialis caput superius (ECRsup), and the flexor antibrachii lateralis superficialis caput superius (FALSsup). In addition, one breast muscle, the coracoradialis (CR), was also heavier in males than in females. A quantitative analysis of muscle fibers processed for myosin ATPase activity showed that, in such “sexually dimorphic muscles” of the female, both fast (twitch) and slow (tonic) muscle fibers were of smaller diameter than in other forelimb muscles of both sexes (all male muscles plus “nondimorphic muscles” of the female). Moreover, both types of fibers were less numerous than in the corresponding muscles of the male. These results suggest that the “sexually dimorphic muscles” are used especially for clasping by the male and are degenerative or subnormal in the female. Slow muscle fibers were neither peculiar to, nor abundant in, these clasping muscles, although they may well be necessary for tonic and prolonged contractions of the forelimb muscles during clasping. The mechanism of sexual dimorphism may be a direct action of androgens on clasping muscles or an indirect action on clasping muscles via the innervating motoneurons.
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  • 48
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    Journal of Morphology 181 (1984), S. 21-28 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Shells from eggs of the turtle Kinosternon flavescens were examined during different stages of development with light and scanning electron microscopy. Prior to initiation of the calcareous layer, organic spheres or cores appear on the outer surface of the shell membrane. Presumably, these cores nucleate deposition of the mineral layer of the eggshell. Growing shell units of the mineral layer are rounded and nodular in shape, crystallites of adjacent shell units do not interlock, and numerous spaces occur between shell units. As growth continues, most of the spaces between shell units are obliterated, and shell units become more elongate in form. The calcareous layer of partially shelled eggs resembles the calcareous layer of flexible-shelled eggs of emydids and chelydrids. Eggshells assume the morphology typical of rigidshelled chelonian eggs only at an advanced stage of shell formation. These observations indicate that rigid and flexible eggshells may form by fundamentally similar mechanisms, with length of shell growth being the primary determinant of whether shells are flexible or rigid.
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  • 49
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    Journal of Morphology 181 (1984), S. 69-86 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hymenopteran venom glands are epidermal glands that have evolved from female accessory reproductive glands. In the honey bee, Apis mellifera L., the venom gland shows many of the fine structural features of primitive glands. A honey bee venom gland is a simple, long, thin, distally bifurcated structure, opening into an ovoid reservoir. Along most of the length of the gland are similar secretory units that have four major components (secretory cells, duct cells, ducts, and end apparatuses), except in the part of the gland proximal to the venom reservoir, where the secretory units resemble those around the venom reservoir. In the latter secretory units a funnel structure occurs between the duct (which is shorter than that of the secretory units of the gland) and the end apparatus. This funnel may be important in protecting the secretory cells around the reservoir from the cytolytic activity of the complex chemical mixture constituting the venom.
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  • 50
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    Journal of Morphology 181 (1984), S. 175-204 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anatomical studies of cephalic bones and muscles combined with cine and high-speed videographic analyses of feeding demonstrate that Amphiuma tridactylum uses two distinct types of suction feeding. Small or relatively immobile prey generally elicit a stationary capture mode in which mouth opening precedes buccal expansion and there is no forward movement of the head of the salamander. Actively moving prey are captured by a rapid strike during which mouth opening and buccal expansion are synchronous and the extent of buccal expansion is greater than in stationary feeding. Differences between these feeding modes may be due to differences in the timing of contraction of the rectus cervicis muscle. Synchronous hyoid and mandibular excursions during the strike are probably generated by simultaneous contractions of the depressor mandibulae and rectus cervicis, whereas delay of hyoid excursions during stationary capture suggests sequential contraction of the depressor and rectus cervicis.
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  • 51
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    Journal of Morphology 181 (1984), S. 161-173 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Silver impregnation of serial histological sections of the tubeworm Chaetopterus variopedatus revealed the presence of a subepidermal nervous system. The anterior nervous system is delimited by the first 11 segments and comprises (1) two dorsolateral cerebral ganglia and lateral instead of ventral nerve cords which are widely separated and thus connected by unusually long commissures, (2) a pharyngeal ganglion in the fourth segment which is connected to the cerebral ganglia by pharyngeal nerves and constitutes along with the pharyngeal plexus a stomatogastric or enteric nervous system, and (3) small, presumably segmental ganglionic swellings along the lateral nerve cords from which emerge commissures and parapodial nerves. No subesophageal ganglion or periesophageal connective could be identified. The lateral nerve cords converge toward the midline in the 12th segment to form the posterior nervous system comprising a pair of ventromedian nerve cords with their repetitive segmental ganglia from which emerge numerous short commissures and three segmental nerves coursing toward the dorsal and ventral regions of parapods and toward the neuropod. Light and electron microscopic investigations of cerebral and segmental ganglia showed an arrangement of inner neuropile and of unipolar neuron somata at the periphery. The neuropile comprises numerous neurites ranging in diameter from 0.5 to 10 μm and making polarized or symmetrical synaptic junctions with each other. The pharyngeal ganglion consists of a similar neuropile and of a large mass of cell bodies which is traversed by an elaborate network of sinuses and harbors three types of neurosecretory cells in addition to the conventional neuron somata. These findings are interpreted in the framework of the highly specialized morphological features and habits of Chaetopterus, and the welldeveloped stomatogastric system is considered to be related to control of the feeding activities.
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  • 52
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    Journal of Morphology 181 (1984), S. 297-303 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Whenever individuals of the freshwater sponge Ephydatia fluviatilis belonging to different strains come into contact, they reject each other by building a nonmerging front. The present work describes the development, the structure, and the nature of the barrier secreted between two individuals. The observations reported give unequivocal data about the collagen nature of the incompatibility barrier. First, ultrastructural investigations reveal the presence of fibrils and microfibrils which are, respectively, typical of collagen and spongin. Second, incorporation of tritiated proline, a characteristic precursor of collagen and related products, is particularly intense in the front. The involvement of several cell types in the barrier formation is discussed. The allogeneic incompatibility reaction between E. fluviatilis individuals appears very close to the process of allograft chronic rejection that we formerly described for some marine sponges. Both phenomena are basically analogous to the process which fixes to and isolates the sponges from their substrate.
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  • 53
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    Notes: Motor units of the medial gastrocnemius (MG) and the single lateral gastrocnemius/soleus (LG/S) muscles of the opssum (Didelphis virginiana) were found to have uniformly slow contraction times relative to homologous muscles of the cat. Though a broad range of peak tetanic tensions was found among motor units from both muscles, most of the motor units were quite large relative to tension of the whole muscle. Comparison of the relative sizes of motor units showed that those of LG/S are significantly larger and slower than the units of MG. This suggests that the motor units of the two muscles may be differentially recurited during different behaviors.All of the MG and LG/S motor units were highly or moderately resistant to fatigue. Histochemical staining for NADH-diaphorase activity indicated consistently high levels of the enzyme in all of the fibers of both muscles. Apparently, all of the fast motor units consist of fast oxidative/glycolytic (FOG)-type muscle fibers. Our data provide functional evidence that the types of myofibrillar ATPase demonstrated by Brooke and Kaiser ('70), are not necessarily correlated to physiological classification of fiber types as slow oxidative (SO), fast oxidative/glycolytic (FOG), and fast glycolytic (FG) (Peter et al., '72).Perhaps compartmentalization of muscle fiber types may be a first step in the separation of muscles into multiple heads during the evolution of specialization to diverse locomotor habits among the mammals.
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  • 54
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    Notes: Sensory epithelia of the oral tube, a fungiform body anterior to the tentacles and of the terminal knob of tentacles, were studied in Ovatella myosotis by electron microscopy. All three epithelia consist of columnar support cells, sensory cells, and, except in the oral tube, numerous goblet cells. The epithelia differ significantly in their apical differentiations. In the oral tube an outer layer is formed by irregularly bent villi of support cells completely embedded in a surface coat. Cilia and cytofila of the dendrites of sensory cells intertwine throughout the entire depth of the villous layer. In the fungiform sensory body some of the villi of support cells are singly branched. Their basal region is free of a surface coat. In this region cytofila and cilia of dendrites form a spongy layer, some cytofila extending into the surface coat. In the tentacular terminal knob the villi of the support cells branch dichotomously once or twice, a single villus thus ending with 2-4 tips. Only these terminal twigs are invested with the surface coat. The cytofila and dendritic cilia are confined to a broad spongy layer underneath. Three types of dendrites are present. They differ in their number of cilia, structure of basal bodies and occurrence in the three epithelia. Dendritic cytofila are most abundant in the tentacular terminal knob and least numerous in the oral tube. The observations are discussed with respect to corresponding epithelia in other pulmonates, the homology of the fungiform body, and possible functional correlates of structural features.
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  • 55
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    Journal of Morphology 182 (1984), S. 63-69 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Renal tubules in the dog shark, leopard shark, and red skate were examined histologically and analyzed histochemically for enzymes. Cells of the distal and collecting tubules exhibit extensive interdigitations and large intercellular spaces, suggesting that these tubules are sites of sodium reabsorption. Although Na-K-ATPase is very scarce to nonexistent in the distal and collecting tubules, very intense carbonic anhydrase activity in these segments indicates that they secrete large amounts of hyrogen ion and reabsorb sodium by H+/Na+ exchange process. Epithelial cells of the necks are not interdigitated, tightly join adjacent cells, and have low enzyme activities. They seem to be passively permeable to the water. Necks are attached to the distal tubules with scant intervening stroma. It seems likely that the stroma has a high osmotic pressure resulting from absorption of solutes in the distal tubules. Water may be reabsorbed from necks to stroma because of a concentration gradient of the solutes distributed between these sites.
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  • 56
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    Notes: Light and electron microscopy were used to examine the morphology of the mucosa of the diverticulum, anterior intestine, and transition zone in prefeeding and spontaneously feeding adult lampreys (Petromyzon marinus L.). Absorptive (either types A or B), ciliated, and enteroendocrine cells are present in all regions but the diverticulum and anterior intestine also possess zymogen (secretory) cells. Type A absorptive cells are restricted to the diverticulum and the rostral one-third of the anterior intestine and are characterized by abundant mitochondria and an extensive smooth tubular network. Type B absorptive cells, in the remainder of the anterior intestine and the transition zone, possess small numbers of these organelles but in the transition zone also have inclusion bodies. During feeding, abundant lipid droplets and lipoprotein (VLDL) accumulate in the cytoplasm of both types of absorptive cells and in the lateral intercellular and the perivascular spaces. Lipid is present to a limited extent in ciliated cells and is encountered only rarely in enteroendocrine and zymogen cells. Although the animals are obligate sanguivores, there is little evidence of iron within these mucosal cells. It is suggested that intestinal efficiency displayed by this animal is due in part to ion transport in osmoregulation in type A cells, lipid absorption in types A and B cells, and digestion through enzymes in zymogen cells.
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  • 57
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    Journal of Morphology 182 (1984), S. 71-83 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fourteen species of leiognathid fishes (Perciformes, Leiognathidae) from the Philippine Islands, Thailand, Japan, Indonesia, and Palau were examined for accessory secondary sexual dimorphism. Thirteen species exhibit either external dimorphism (a clear patch of skin on the flanks of males, a large clear patch of skin on the opercular margins of males, or a flank stripe in males) or internal dimorphism (large light organs in males) or both. Eight of the 14 species (and possibly as many as 11) exhibit both forms of sexual dimorphism. Two species show only internal light organ volume dimorphism, and one species shows neither external nor internal dimorphism. Sexual dimorphism is thus very common in leiognathids. The externally dimorphic skin patches are closely associated with the internally dimorphic light organ system in seven species (and possibly as many as ten), indicating a potential for light emission through the clear patches. A bioluminescent signaling function by males is therefore suggested for the sexual dimorphism in leiognathids, which may play an important role in the schooling behavior as well as in species and sexual recognition of these coastal fishes.
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  • 58
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    Journal of Morphology 182 (1984), S. 1-37 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Among egg-brooding hylid frogs there is much interspecific variation in the degree of development of the young at hatching. In certain species of Gastrotheca the eggs hatch into free-living tadpoles, whereas in others (and in the genera Amphignathodon, Cryptobatrachus, Stefania and Hemiphractus) the eggs hatch directly into frogs. We examined the oral anatomy of tadpoles and embryos of 22 species of egg-brooding hylids in order to determine the morphological differences between free-living larvae and embryos of species having direct development. All free-living Gastrotheca larvae are morphologically similar and have a large array of oral structures directly associated with a suspension feeding way of life. Among those egg-brooding hylids without free-living larvae there is a complete gradation from those with all of the free-living tadpole oral structures to those with none. Different lineages retain different vestiges of free-living larval morphology, suggesting that direct development has evolved multiple times among these frogs. All of the morphological patterns in the direct-developing embryos can be accounted for by simple truncation or acceleration of the normal tadpole developmental program. We explore the possibility that certain Gastrotheca species with tadpoles may have evolved from species that lack larval stages. The development of oral structures in egg-brooding hylids provides insight into the phylogenetic significance of these charactes in other groups of anurans. Most significantly they reinforce the idea that microhylids evolved from ranoidlike ancestors.
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  • 59
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    Journal of Morphology 182 (1984) 
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  • 60
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    Notes: With the use of rabbit antisera against crustacean hyperglycemic hormone (CHH), it is possible to describe a distinct immunopositive reaction in a group of neurosecretory cells in the medulla terminalis ganglionic X-organ2 (MTGX2), in the MTGX-sinus gland tract, and in a considerable part of the sinus gland from several species of prawns belonging to the Palaemonidae. By introductory studies on the CHH system in Palaemon serratus, we can postulate a sequence in the activity cycle of the CHH-producing cells on the basis of differences in staining intensity of the immunoreaction and such morphometric parameters as cellular and nuclear diameter. By studying the CHH-producing system in combination with variations in the glucose level of the blood, an “inverse relationship” is observed between the number of immunoreactive cells and the blood glucose level during different periods of the year as well as during different stages of the molting cycle. A “shift in phase” of this correlation during the diurnal cycle suggests that several rhythmical phenomena may play a role in the regulation of glycemia in Crustacea.
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  • 61
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    Journal of Morphology 182 (1984), S. 115-123 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A large mechanosensory campaniform sensillum (LCS) is found close to the flagellum/pedicellus joint in the antennae of the blowfly Calliphora erythrocephala. The LCS possesses a single sensory cell, enveloping cells and a cuticular stimulus-conducting structure. The distal part of the sensory process is developed as a tubular body and is connected to the two parts of the stimulusconducting apparatus. The sensory cell is characterized by the complete absence of ciliary structures in the transition zone between dendrite and sensory process.
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  • 62
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    Journal of Morphology 182 (1984), S. 95-113 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A three-dimensional muscle model with complex geometry is described and tested against experimental data. Using this model, several muscles were constructed. These muscles have equal optimum length but differ in architecture. The force exerted by the constructed muscles, in relation to their actual length and velocity of shortening, is discussed. Generally speaking, the constructed muscles with considerable pennation have great fiber angles, a great physiological cross section, a narrow active and steep passive length-force relation, and a low maximal velocity of shortening. The maximal power (force times velocity) delivered by the constructed muscles is shown to be almost independent of the architecture of the muscles. The steepness of the passive length-force relation is determined mainly by the shortest fibers within the group of constructed muscles, wheras maximal velocity of shortening and the width of the active length-force relation are determined mainly by the longest fibers.The validity of the three-dimensional muscle model with respect to some morphological and functional characteristics is tested. Length-force relations of constructed muscles are compared with the actual length-force relations of mm. gastrocnemii mediales and mm. semimembranosi of male Wistar rats. Moreover, actual fiber angle, fiber length, and muscle thickness of three mm. gastrocnemii mediales are compared with values found for constructed muscles. It is concluded that the three-dimensional muscle model closely approximates the actual muscle form and function.
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  • 63
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    Journal of Morphology 182 (1984), S. 125-136 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Horseradish peroxidase histochemical studies of afferent and efferent projections of the trigeminal nerve in two species of chondrostean fishes revealed medial, descending and ascending projections. Entering fibers of the trigeminal sensory root project medially to terminate in the medial trigeminal nucleus, located along the medial wall of the rostral medulla. Other entering sensory fibers turn caudally within the medulla, forming the trigeminal spinal tract, and terminate within the descending trigeminal nucleus. The descending trigeminal nucleus consists of dorsal (DTNd) and ventral (DTNv) components. Fibers of the trigeminal spinal tract descend through the lateral alar medulla and into the dorsolateral cervical spinal cord. Fibers exit the spinal tract throughout its length, projecting to the ventral descending trigeminal nucleus (DTNv) in the medulla and to the funicular nucleus at the obex. Retrograde transport of HRP through sensory root fibers also revealed an ascending bundle of fibers that constitutes the neurites of the mesencephalic trigeminal nucleus, cell bodies of which are located in the rostral optic tectum. Retrograde transport of HRP through motor root fibers labeled ipsilateral cells of the trigeminal motor nucleus, located in the rostral branchiomeric motor column.
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  • 64
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    Journal of Morphology 182 (1984), S. 153-168 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two types of nerve cells, sensory and ganglion cells, were identified in the epidermis of the hypostome of Pelmatohydra robusta by light and electron microscopy. In the study of distribution of these cells, the presence of a circumhypostomal nerve ring in the epidermis was revealed, although hydras have been considered to possess only a diffuse nervous system or socalled nerve net. The nerve ring, which encircled the hypostome, was constituted by several clusters of ganglion cells, thick bundles of many neurites connecting these clusters, and a small number of individual ganglion cells located along the bundles. In the nerve ring, some of the lamellae protruding from the ganglion cells were frequently myelinated and wrapped the cell bodies of neighboring ganglion cells, and other lamellae were arranged in concentric circles.
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  • 65
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    Journal of Morphology 182 (1984), S. 137-152 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epithelium of the posterior intestine and hindgut of recently metamorphosed adult lampreys (Petromyzon marinus L.) prior to and during spontaneous feeding was examined using light and electron microscopy. These two regions differ slightly in their general morphology but possess the same mucosal cell types. Included are caveolated absorptive and mucous cells, which are not present in more cephalic regions of the intestine, and ciliated and enteroendocrine cells. During feeding, the caveolated cells undergo dramatic transformation in their structure, namely, through the acquisition of numerous heterophagic vacuoles. Due to their morphology and to the fact that there are low amounts of lipid, it is suspected that caveolated cells are primarily involved in the absorption of protein components from the ingested host blood and body fluids. Iron in caveolated cells may result from the degradation of ingested heme or reflect the excretion of bile products at this location in the intestine. Mucous cells are likely responsible for lubrication of the luminal surface and may be important as a stem cell for the mucosal epithelium.
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    Journal of Morphology 182 (1984), S. 169-178 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This investigation describes the morphogenesis of the type I pneumocyte from the neonatal stage to the age of 3 months. Cells lining subpleural air spaces were photographed from electron microscopic serial sections and a three-dimensional representation of each cell was obtained by transferring the contours of the cell membranes from micrographs to transparent plastic sheets which were then spaced to scale and stacked. The portion of the reconstructed cell surface taking part in the formation of the blood-airbarrier increased extensively in postnatal stages when compared with reconstructed cells of prenatal stages. Reconstructed cell-surface irregularities decrease during distension. A cytoplasmic plate seen in the last stage studied may represent a forming alveolar pore.
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  • 67
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    Journal of Morphology 182 (1984), S. 179-196 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three hypothetical models of tongue movement of the walrus during suction feeding are examined. These models encompass the entire range of simple tongue retraction movements possible by examining 1) movement of the tongue directly to the rear following the curvature of the palate, 2) to the rear and ventrally in a straight line, and 3) ventrally in a straight line. The percent of muscular force available from the hyoglossus, genioglossus, and styloglossus that could be applied toward retraction as predicted by each model is calculated. The resistance that the tongue would provide during retraction is calculated using projected tongue areas and is combined with the above data from the muscles to provide an estimate of the percent of the total available force that is needed to retract the tongue for each model. A separate examination of the direction of tongue-induced wear striations on the palatal and lingual aspects of the teeth is used to help support or reject the three models.The model where the tongue is moved directly to the rear is supported by studies of both muscle force and tooth wear. In the mammalian groups that were compared to the walrus, there is a great deal of interspecific variation in movements of the tongue during suction feeding; no two groups can be considered to have identical stereotyped tongue movements.
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    Journal of Morphology 182 (1984), S. 221-225 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The retina of the chick contains retinal cells of a morphology very similar to that of the horizontal cells, but the perikarya, axons, and axon terminals lie in the inner plexiform layer. The discovery of this neuronal ectopia appears to support the idea that some horizontal and amacrine cells derive from a common, freely migrating cell.
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  • 69
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    Journal of Morphology 182 (1984) 
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  • 70
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    Journal of Morphology 182 (1984), S. 227-244 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The cranial and cervical osteology of the European oystercatcher, Haematopus ostralegus L. is completely described from both whole skeletons and spirit specimens. Contrary to previous reports, the postorbital ligament shows variability in bifurcation and attachment, with the posterior branch, where present, attaching either to the suprameatic process or the zygomatic process. In addition, the quadrate ligament, which had been described as originating from the suprameatic process, appears instead to attach to the zygomatic process in some specimens. The caudal mandibular fenestra, earlier considered absent in oystercatchers, is present in all specimens examined. The cranium is additionally distinguished by a number of features which may be unique to oystercatchers. A fourth, previously unrecorded, division of the maxillopalatine strut is present, while the palatine process of the premaxilla is reduced to a thickening along the edge of the premaxillary process of the palatine. The distinctiveness of the oystercatcher cranium is particularly evident in the area of the quadratomandibular articulation, which possesses features potentially important for stabilizing the joint. A deep retroarticular notch is present, guiding a large medial jugomandibular ligament along the posterior margin of the articulation. A lateral mandibular tuberosity, which is received dorsally by an emargination of the jugal arch and quadrate, may act as an osteological brace, preventing posterior shifting of the closed mandible. The 15 cervical vertebrae are divided on the basis of structural criteria into three sections.
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    Journal of Morphology 182 (1984), S. 197-219 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Many climbing mammals are able to reverse normal hind foot posture to effect the grip necessary to descend headfirst or to hang upside down. Such hind foot reversal is known in sciurids, procyonids, felids, viverrids, tupaiids, prosimians, and marsupials. The joint movements involved, however, have never been documented unequivocally although various interpretations (some contradictory) have been made. We report here radiographic data from species of the genera Didelphis, Felis, Nasua, Nycticebus, Potos, Sciurus, and Tupaia. In the six eutherians studied, three joints are involved, and there is a common pattern in the mechanism: crurotalar plantarflexion, subtalar inversion, and transverse tarsal supination. Hind foot reversal represents the development of an unusual degree of excursion at these joints, rather than the appearance of any new type of movement. In Didelphis the mechanism is quite different: a bicondylar, spiral tibiotalar joint is the principal site of inversion/abduction movements. This specialization is characteristic of didelphids and phalangerids, and occurs in the extinct multituberculates as well; it is not found in macropodids (which are like eutherians in crurotalar joint structure) or other marsupial families. This diversity in pedal structure and function is evidently the result of parallel evolution from the type of tibiotalar joint of cynodonts and early mammals. In Morganucodon the bulbous, hemispheroidal proximal surface of the talus bears two tibial facets. These facets are represented in didelphids and multituberculates as sulci, whereas in macropodids and eutherians they developed as the proximal and medial surfaces of the talar trochlea. Among living mammals, the primitive hemispheroidal joint is retained among monotremes as a ball and socket joint.
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    Journal of Morphology 182 (1984), S. 245-255 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The sequence of appearance of the 17 different skull bones in the oriental fire-bellied toad, Bombina orientalis, is described. Data are based primarily on samples of ten or 11 laboratory-reared specimens of each of 11 Gosner developmental stages (36-46) representing middle through late metamorphosis. Ossification commences as early as stage 37 (hind limb with all five toes distinct), but the full complement of adult bones is not attained until stage 46 (metamorphosis complete). Number of bones present at intermediate stages is poorly correlated with external morphology. As many as four Gosner developmental stages elapse before a given bone is present in all specimens following the stage at which it may first appear. The modal ossification sequence is frontoparietal, exoccipital, parasphenoid, septomaxilla, premaxilla, vomer, nasal, maxilla, angulosplenial, dentary, squamosal, quadratojugal, pterygoid, prootic, interfrontal, sphenethmoid, and mentomeckelian. Most specimens are consistent with this sequence, despite the poor correlation between cranial ossification and external development as assayed by Gosner stage.The timing of cranial ossification in Bombina orientalis differs in many respects from that described for two other, distantly related anurans, the leopard frog (Rana pipiens) and the western toad (Bufo boreas). These include the total number and sequence of appearance of bones, and the timing of ossification relative to the development of external morphology. Interspecific variation may reflect differences in the timing of the tissue interactions known to underlie skeletal differentiation and evolution.
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    Journal of Morphology 182 (1984), S. 257-277 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The ultrastructure of the Malpighian tubules, ileum, rectum, anal canal, and anal papillae of larvae of the mosquito Culiseta inornata was examined. The Malpighian tubules, rectum, and anal papillae have many of the ultrastructural features characteristic of ion transport tissues, i.e., elaboration of the basal and apical membranes and a close association of these membranes with mitochondria. The Malpighian tubules possess two cell types, primary and stellate. The larval rectum of C. inornata is composed of a single segment containing a homogenous population of cells. In this respect, the larval rectum of C. inornata is distinct from that of saline-water species of Aedes. The cells in the larval rectum of C. inornata, however, closely resemble those of one cell type, the anterior rectal cells, of the saline-water mosquito Aedes campestris with regard to cell and nuclear size, the percentage of the cell occupied by apical folds, and mitochondrial density and distribution. No similarities can be found between the rectum of C. inornata and the posterior segment of the saline-water Aedes, which functions as a salt gland. On this basis, we have postulated that the rectum of C. inornata does not function as a site of hyperosmotic fluid secretion. The ultrastructure of the anal papillae of C. inornata is consistent with a role in ion transport. The significance of these findings to comparative aspects of osmoregulatory strategies in mosquito larvae is discussed.
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    Journal of Morphology 182 (1984), S. 279-294 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Among cockroaches in the subfamily of Oxyhaloinae, the adult males produce two essential and successively active chemical signals: the sex pheromone attracting females from a distance secreted by the sternal glands, and the aphrodisiac required for mating which is secreted by the tergal glands. The adult males of the seven species studied, Nauphoeta cinerea, Henschoutedenia flexivitta, Leucophaea maderae, Jagrehnia madecassa, Gromphadorhina portentosa, G. laevigata, and G. chopardi, possess well-developed sternal and tergal glands whose number varies according to the species and methods of mating (three to six sternal glands and four to seven tergal glands). These glands are basically composed of type three glandular units (glandular cell + duct cell) and type 2 cells (modified oenocytes) which exhibit no significant external cuticular modification except for tergite 2 of L. maderae. The extreme variance in development of these glands can be linked to sexual behavior. The hypothesis put forward here is that of a regressive evolution of the tergal glands, related to a modification of the role played by the aphrodisiacs which they secrete.
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    Journal of Morphology 182 (1984), S. 295-305 
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    Notes: The gross morphology and histology of the alimentary tracts of three species of glassy perchlet; Ambassis productus, A. natalensis, and A. gymnocephalus from estuaries on the southeast coast of Africa were investigated. The anatomy of the digestive tracts in all three species was found to be similar. Well-developed dentition and pharyngeal teeth together with a distensible stomach and a low relative gut length (RGL) suggest a predatory and carnivorous habit for all three species.The relative gut lengths of Ambassis species from different estuarine systems are compared‥ Differences in RGL for A. productus and A. natalensis from the Kosi and St Lucia systems with fish from Mdloti estuary are discussed. It is suggested that decreased RGL for fish at Mdloti is attributable to decreased food availability and not to a lack in the calorific content of their diet.Histological investigation revealed the presence of the following regions: a pharynx; an oesophagus; a stomach differentiated into cardiac and pyloric regions; a duodenum or upper intestine; an ileum or lower intestine; and a rectum. Pyloric and rectal sphincters are present. The tunics of the above regions are described. The epithelium of the oesophagus contains taste buds and numerous mucus cells, and varies from stratified anteriorly to simple columnar posteriorly. The muscularis comprises dorsally and ventrally located inner muscle bundles and an outer circular layer. Both layers consist of striated fibres.Gastric glands are present in the mucosa of the cardiac stomach but are absent in the pylorus. Columnar absorbing cells and goblet cells are present in the epithelium of the upper and lower intestine. The rectum is distinguished from the intestine by the proliferation of mucous-secreting cells which are thought to aid defecation.
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    Journal of Morphology 182 (1984), S. 317-337 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cross sections through the middle segment of the anuran rectus abdominis muscle were analyzed morphometrically at nine stage of development, from early larval life through full maturity. The numbers, sizes, and relative distributions of twitch and slow muscle fibers, newly differentiated fibers, degenerating fibers, and satellite cells were determined at each stage. The data indicate that the muscle increases slowly in size and fiber content during early larval life. New fibers appear to form primarily along the medial margin of the muscle. During mid-larval stages, when thyroid hormone levels are rising, new fibers form throughout the medial portion of the muscle. At a slightly later stage, fibers in the lateral region of the muscle begin to degenerate. Structurally normal presynaptic elements are present on both degenerating fibers and the empty basal laminae of fibers that had been removed by phagocytes. Both fiber formation and fiber loss slow during midmetamorphic climax, at the time when thyroid hormone levels reach a peak in anurans and begin to decline. Degenerating fibers appear within the body of the muscle at the end of metamorphosis. By the end of the second postmetamorphic month, neither degenerating nor newly differentiated fibers are present. The muscle continues to grow through adult life primarily by fiber hypertrophy.
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    Journal of Morphology 182 (1984), S. 307-316 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The adrenergic innervation of structures in the gills of brown and rainbow trout was studied with catecholamine fluorescence histochemistry.In the arterio-arterial vascular pathway, there was an innervation of the afferent and efferent lamellar arterioles, but the afferent and efferent filamental arteries and the secondary lamellae were devoid of any fluorescent nerve fibres. In S. trutta only, there was an additional innervation of the afferent and efferent branchial arteries and the base of the efferent filamental artery.The innervation of the arterio-venous vascular pathway was similar in both trout species. Many fluorescent nerve fibres were found on nutritive arterioles in the gill arch and interbranchial septum, and in the core of each filament between the surface epithelium and the wall of the filament venous sinus. No fluorescent nerve fibres were observed at the origins of the capillaries arising from the efferent filamental artery.The sympathetic nerve supply is provided to the gills mainly through the posttrematic nerve, with an occasional small contribution through the pretrematic nerve.The presence of adrenergic nerves in the gills is discussed in relation to the regulation of blood flow through the arterio-arterial and arterio-venous pathways.
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    Journal of Morphology 182 (1984), S. 339-354 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The presence of both book lungs and a tracheal system in many spiders raises the question of the functional significance of this double respiratory system. The present physiological and morphometric study of the house spider (Tegenaria spp.) reveals that the diffusing capacity (Dto2) of the lungs alone suffices during rest and following exercise to meet measured rates of oxygen consumption (\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^{\rm.} $\end{document}o2) at driving pressures (ΔPto2) similar to those calculated for vertebrate lungs. During moulting ΔPto2 may rise to more than double the vertebrate values, implying the possible insufficiency of book lungs during this critical life phase. Resting \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^{\rm .} $\end{document}o2 is greatest (92 mm3/h · g) during the early morning and lowest (66 mm3/h · g) near midday: during moulting \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^{\rm .} $\end{document}o2 rises to 278.7 mm3/h · g. In spiders recovering from exercise \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^{\rm .} $\end{document}o2 is consistently greater than during rest: neither value is significantly reduced by blockage of the tracheal stigmas. Regression calculations of morphometric values for a hypothetical 100-mg Tegenaria yield a total lung volume of 0.578 mm3, a pulmonary surface area of 69.8 mm2, and a surface-to-volume ratio of 120.89 mm2/mm3. In spite of the similar thickness of the chitinous and hypodermal components of the air-hemolymph barrier (each ca. 0.2 μm in nonmoulting animals), the low permeability of chitin for oxygen makes this layer the greater barrier to diffusion. For a 100-mg specimen Dto2 is 3.5 mm3/h · torr: similar to that of a turtle (Pseudemys) on a gram-body weight basis.
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    Journal of Morphology 191 (1987), S. 25-36 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The major anatomical divisions of the cerebellum of the European eel, i.e., corpus cerebelli, lobus vestibulolateralis, and valvula, were studied morphologically and morphometrically. There were differences in cerebellar cytoarchitecture and gross morphology in two stages of the eel life cycle, the trophic stage (yellow eel), and the reproductive stage (silver eel), which are characterized by different degrees of swimming activity. The principal differences between silver and yellow eels in the cytoarchitecture of the corpus cerebelli and the lobus vestibulolateralis were in distribution of Purkinje or Purkinje-like cells in the molecular layer, which is wider in silver eels, in part because of a decreased thickness of the granular cell layer. In the silver eel, the scattering of Purkinje cells was more evident in the lobus vestibulolateralis where the molecular layer is also thicker. The data indicate the transition from the yellow eel to the silver eel is characterized by a migration of granule cells from the ganglionic cell layer to the internal granular layer and by a further development of molecular layer components, e.g., parallel fibers, Purkinje-cell dendrites, etc. In contrast, the thickness of the granular layer and of the Purkinje cell layer, limited to the lower part of the valvula, decreased. There is also a slight increase of cerebellar volume in the silver eel. The volume of the lobus vestibulolateralis was constant. Hypertrophy of the valvula and eminentiae granulares is observed and is due to the migration of cells from the granular layer of the corpus cerebelli whose volume slightly decreases. Perhaps the lobus vestibulolateralis also contributes to the increased volume of eminentiae granulares. Our findings suggest that the cerebellum continues to develop during the passage from the trophic to the reproductive stage of the eel. The appearance of new afferents from the lateral line which becomes more visible in the silver eel probably completes cerebellar ontogeny.
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    Journal of Morphology 191 (1987), S. 107-107 
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    Journal of Morphology 191 (1987), S. 131-144 
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    Notes: Xenopus laevis froglet forelimbs normally respond to amputational injury by forming a heteromorphic cartilaginous rod-shaped outgrowth. However, partial denervation of a forelimb by ablation of the N. radialis or the N. ulnaris, followed in 2 days by amputation through the mid radius-ulna, results in a size deficiency of the regenerative outgrowth 14 and 21 days postamputation. The decreasing quantity of forelimb innervation, as a result of partial denervation by 55 or 45%, apparently has a graded effect on the cell population and on the extent of cartilage development in the outgrowth. As a consequence of amputational injury, a nerve independent response of the periosteum was also found. This response produced considerable thickening in the periosteum and was due to cell proliferation in both the control and denervated cases.
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    Journal of Morphology 191 (1987), S. 193-204 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nerve pathways in the praesoma are described for a member of the class Eoacanthocephala for the first time. Eleven nerves, five paired and one single, are traced from the cerebral ganglion to their associations with the musculature of the body wall, neck sense organs, and the musculature of the proboscis wall and the invertor muscles of the proboscis. The structure and location of the stutzzelle and series of nerve endings in the hypodermis of the body wall and at the apex of the proboscis are described.
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    Journal of Morphology 191 (1987), S. 215-216 
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    Journal of Morphology 191 (1987), S. 225-232 
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    Topics: Biology , Medicine
    Notes: Serial transverse paraffin sections of intrafusal muscle fibers of spindles from the extensor pollicis and the extensor digitorum communis of ducks show that only one type of intrafusal muscle fiber exists, based on the mid-equatorial nucleation pattern, diameter, and length. Although the overall range in fiber diameter at the mid-equatorial region is between 4.2-20.0 μm, the average caliber is 10.4 ± 3.18 μm (S.D.) for spindles of the extensor pollicis and 9.3 ± 2.11 μm (S.D.) for spindles of the extensor digitorum communis muscles. The range in spindle length for the extensor pollicis is 290-2,090 μm, average 1,120 ± 569 μm (S.D.), and for the extensor digitorum communis 1,160-2,500 μm, average 1,745 ± 367 μm (S.D.). Therange in number of fibers per spindle for the extensor pollicis muscle is 5-12, average 8.2, and for the extensor digitorum muscle it is 1-11. In the extensor digitorum communis, there appear to be two groups, based on fiber number. Spindles of one group have a range of 5-11 fibers per spindle with an average of 7.2, whereas the second group has a range of 1-4 with an average of 2.7 fibers per spindle. The second group of spindles constitutes 52.5% of the 40 spindles studied, and of these 7.5% were monofibril spindles, 15.0% difibril, 17.5% trifibril, 12.5% quadrifibril spindles.
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    Journal of Morphology 192 (1987) 
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    Journal of Morphology 191 (1987), S. 265-288 
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    Topics: Biology , Medicine
    Notes: Each of the paired salivary glands of third instar larvae of the humpbacked fly Megaselia scalaris is a bag-like structure with a short neck region from which a single duct emerges. The two ducts form a common duct that empties into the ventral region of the pharynx near the mouthparts. The wall of the glands and ducts consists of a simple squamous epithelium that rests upon a connective tissue layer. Cells in the neck are less flattened than those found elsewhere. The basal surfaces of the cells are infolded most deeply in the neck and the least in the duct. The apical surfaces of the cells possess microvilli except in the duct where the apices of the cells are covered by a complex extracellular layer. This layer displays circularly arranged folds that accommodate a thread-like supportive structure resembling taenidial threads of tracheae. Elaborate junctional complexes are associated with the lateral surfaces of the cells. Elements of these complexes include a zonula adherens, a series of pleated septate desmosomes, and conventional desmosomes. The cytoplasm of the glandular cells is filled with RER and other organelles normally seen in cells that export proteins and mucosubstances. Secretory material found in the lumens of the glands reacts only moderately with the PAS procedure but more strongly with alcian blue and methods that demonstrate proteins. The nuclei of the glandular cells contain single large nucleoli and polytene chromosomes whose banding is rather indistinct. Treatment with EDTA produces detrimental effects on all of the foregoing ultrastructural features of the glands and ducts.
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    Journal of Morphology 192 (1987), S. 27-42 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fate and possible roles of the cytoskeleton in the process of conjugation in the hyptrich ciliate Euplotes aediculatus were investigated. Following the coalescence of the plasma membranes of the conjugant cells, a fusion zone or bridge of cytoplasm contributed by both partners is constructed. The sub-alveolar microtubule layers of the vegetative cell cortex remain in place to define the fusion zone boundaries after cell union. The initial fusion zone consists primarily of featureless ground cytoplasm; soon the ground plasm becomes crowded with microtubules and anastomosing smooth endoplasmic reticulum, which become displaced only late in conjugation as the migratory pronuclei are exchanged between partners. Fusion zone microtubules, functioning in some undetermined way, may be involved in the nuclear migration. Resorption of the posterior portion of each partner's buccal apparatus results in the degradation of the component cilia within acid phosphatase-positive autophagic bodies. Silver staining for light microscopy shows that the late fusion zone contracts forward from the posterior border, then constricts to separate the conjugants. In some separating pairs remnants of a microfilamentous assembly are seen at the posterior edge of the fusion zone; the full extent of this system may be masked by partial degradation due to osmium tetroxide fixation. Treatment of conjugants for 6 hours with cytochalasin B prevents separation, possibly through inhibition of the actin-like microfilament assembly in the fusion zone. The observations and experiments favor a model of cell separation following conjugation in which the fusion zone is resorbed by motile or contractile processes occurring within or around the fusion bridge itself.
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    Journal of Morphology 192 (1987), S. 101-111 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of the tentacle, a chemosensory and perhaps tactile structure unique among vertebrates to gymnophione amphibians is described in Dermophis mexicanus and Gymnopis multiplicata. The tentacle is associated with the vomeronasal organ and its glands, and utilizes several structures usually associated with the eye, such as the Harderian gland, the retractor and levator muscles, and their nerves. Innervation of the tentacle itself is from the trigeminal nerve. We present an hypothesis that the tentacle originated from modified eye components.
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  • 89
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    Journal of Morphology 192 (1987), S. 145-159 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two types of calcareous spicules occur abundantly in Herdmania momus, a solitary pyurid ascidian with a worldwide warm water distribution. The large spindle-shaped body spicules are 1.5-2.5-mm long and are located primarily in the mantle, siphons, and branchial basket. Each body spicule possesses 100 or more rows of overlapping, unidirectional fringing spines. Numerous body spicules occur regularly spaced within a long common sheath of complex structure, and there are many sheaths per animal. Between neighboring body spicules and overlying the fringing spines are the tightly connected pseudopodial sclerocytes. Spine formation is hypothesized to occur within these cells. The body spicules apparently continue to increase in size throughout the animal's life.The tunic spicules are about one tenth the length of the body spicules. They have 20-40 rows of unidirectional nonoverlapping fringing spines and a mace-shaped spiny base that anchors them at the tunic surface. They form quickly in individual spicular envelopes inside the tunic blood vessels over a 4-5-day period. Each tunic spicule then leaves its surrounding envelope and blood vessel, passes into the tunic, and ultimately protrudes through the outer surface of the tunic. An organic covering inside the envelope closely adheres to the tunic spicules and stains with toluidine blue. Dissolution of the CaCO3 mineral phase by EDTA or EDTA-cetylpyridinium chloride-formaldehyde reveals an intricately patterned organic matrix within or upon which the spicules develop.
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  • 90
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    Journal of Morphology 192 (1987), S. 161-179 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In all species of phylactolaemates, an individual successively produces daughter buds. Individual daughters are designated, according to the order of appearance, as first bud, second bud, and so on. The first bud appears precociously, while the mother is a pear-shaped vesicle. The idea of regarding a main bud, a duplicate bud, and an adventitious bud as a set is not tenable. In the budding region, the cystidal wall shows a constant wavy movement. In Plumatella colonies, branching occurs only when and where a bud of the second or higher order grows up to a zooid. A branch is composed of longitudinally arranged first zooids with the only exception being the most proximal one. The proportion of first zooids in a colony increases in the order of P. casmiana, P. emarginata, and P. repens. The frequency of branching, therefore, decreases in this order. The ancestrula germinated from the statoblast shows the highest activity of budding. The tendency that successively produced daughters of the ancestrula grow in alternate directions is most conspicuous in P. emarginata and least conspicuous in P. casmiana. Replacement budding occurs in these three species of Plumatella, but only under unfavorable culture conditions. The colony of Gelatinella toanensis is characterized by composite branches, each consisting of an axial branch composed of a series of first zooids and of stunted lateral branchlets. In Hyalinella punctata, multiple budding does not necessarily result in branching; zooids of different budding orders coexist in a branch. The genus Pectinatella comprises two species, P. gelatinosa and P. magnifica. Both produce massive colonies. In P. gelatinosa, the colony proper is sac-like with the convex basal wall, and the polypides can retract with the digestive tracts straight. Each individual (except the ancestrula) of this species produces a pair of daughter buds which are located bilaterally relative to the median sagittal plane of the mother. A left bud produces its first bud to the right, and vice versa. In P. magnifica, the colony proper is very thin and flat. When polypides are retracted, the digestive tracts are folded characteristically. Based on these and other results, phylogenetic relationships among the phylactolaemates are discussed.
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  • 91
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gonads from three hermaphrodite species of different invertebrate phyla were studied at the ultastructure level. In the flatworm Dugesia biblica, male germ cells in different stages of development lay in the lumen of testicular follicles surrounded by overlapping parietal cells. The intercellular space formed by cytoplasmic extensions running parallel to the testis wall is occluded by septate junctions and by an electron-dense material. In the leech Placobdella costata, the testis is lined by a unicellular layer of parietal cells surrounded by densely packed connective tissue fibers. No specialized occluding junctions were found between the parietal cells; however, plasmalemma thickenings and electron-dense material in the intercellular space near to the testis lumen were observed. In the lumen, germ cells develop connected to cytoplasmic masses, the cytophore. In the land snail Levantina hierosolyma, male and female germ cells are found together in the same acini; each acinus is surrounded by a thick basement membrane. At the periphery of the acinus is the ovarian layer; centrally to it is the testicular layer. Intercalated between them is a double cellular layer of follicular cells and of Sertoli cells. The inter-Sertoli space is characterized by elaborate septate junctions. In the three species studied male germ cells develop within the lumina of compartments isolated from the somatic tissue. This separation is brought about by specialized septate junctions, and/or by electron-dense material between the cells that form the testis walls, and also by densely packed connective tissue fibers. Our observations strengthen the view that a male germ cell-somatic tissue barrier as described in the literature of the testes of vertebrates and of invertebrates from various phyla is of general occurrence in the animal kingdom.
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  • 92
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    Journal of Morphology 192 (1987), S. 269-277 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oocytes from the land hermit crab, Coenobita clypeatus, in various stages of vitellogenesis were examined by light and electron microscopy. Early vitellogenic oocytes are characterized by accumulations of discrete vesicles of endoplasmic reticulum in the perinuclear cytoplasm. As oocytes develop, the endoplasmic reticulum becomes abundant, and numerous Golgi complexes are seen. There is a well developed Golgi-endoplasmic reticulum interaction. Within the confines of the reticulum are discrete intracisternal granules, which can be seen coalescing into electron-dense yolk bodies. Lipid accumulation is seen throughout the cytoplasm. Coincident with the burst of intra-oocytic metabolism are oolemma modifications and micropinocytosis, which provide ultrastructural evidence for extra-oocytic yolk production. The mature oocyte contains numerous yolk and lipid vesicles of varying electron density that comprise both intra- and extra-oocytic substrates.
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  • 93
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 94
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    Journal of Morphology 191 (1987), S. 295-308 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The histochemistry and ultrastructure (SEM and TEM) of the spermatheca of Biomphalaria glabrata was investigated to elucidate the function of this organ and to compare its structure and function to similar organs found in other species. The spermatheca has a debris-filled lumen surrounded by a thin wall of tissue. The cells adjacent to the lumen are of three columnar epithelial cell types. Two cell types have abundant microvilli and mammalian cell-like organelle distribution and morphology. The above cell types differ in the electron density of their cytoplasms, nuclear morphologies, and organelle content. The third cell type differs from the other two in its cytoplasmic makeup. However, the most distinctive difference is the presence of large numbers of cilia at the apical surface with no evidence of microvilli. These columnar cells rest on a basal lamina adjacent to a two to three cell thick muscle layer. The entire organ is surrounded by an adventitia of unusual morphology. Histochemical investigation demonstrated that DNAase, RNAase, and protease are present in the lumen, alkaline phosphatase is associated primarily with the microvilli, small amounts of acid phosphatase are concentrated in the midcell area of the columnar epithelium, and ATPase activity is localized in the muscle cells and just below the absorptive surface of the microvillous cells. The luminal contents and adventitial areas are Sudan Black B positive, all areas of the lumen and organ wall are PAS positive, the cell nuclei and amorphous masses in the lumen showed Feulgen staining, and large vesicles in the columnar cells were Oil Red O positive. Apparently, the spermatheca of B. glabrata is both a digestive and absorptive structure. Although this organ shares functional similarities with those found in opisthobranchs and terrestrial pulmonates, the epithelia of the spermatheca differ dramatically in these groups.
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  • 95
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 96
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    Journal of Morphology 192 (1987), S. 113-123 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In an attempt to investigate the relationships between allometry and locomotory adaptations, we studied the long limb bones of 45 species of insectivores and rodents. Animals ranged from a few grams to about 50 kilograms. Diameter and length of the bones and body mass (when known) were recorded. Regressions of diameter to length, diameter to body mass, and length to body mass were calculated by the least-squares and Model II, or major axis, methods.The results obtained do not agree with the predictions of either the theory of geometric similarity or the theory of elastic similarity. The discrepancies could be due to the fact that animals studied exhibit various modes of locomotion. Moreover, the allometric relationships of the different locomotor patterns are better reflected in insectivores and rodents than in other groups of mammals. The use of a single regression analysis seems to be inadequate when the sample includes a large range of body sizes.
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  • 97
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    Journal of Morphology 192 (1987), S. 181-187 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sensilla that line the upper edge of the lip in the leech Hirudo medicinalis and that contain chemoreceptors required for feeding were examined in the scanning and transmission electron microscopes. The sensilla include two size-classes of ciliated button-like mounds - one about 35 μm in diameter and another about 10 μm in diameter. The larger sensilla are at the center of unpigmented patches of skin which are visible in the light microscope, while the smaller sensilla have not been previously described as distinct structures. Electron microscopy, though not light microscopy, shows that the lip sensilla differ markedly from the segmental sensilla of the leech, which have been shown to mediate mechanoreception and photoreception. In particular, the chemosensory lip sensilla contain multiciliated cells with cilia of a uniform length, whereas the segmental sensilla contain uniciliated cells with long, whip-like cilia, as well as multiciliated cells with short, stiff cilia. Thus, the two types of sensilla differ morphologically as well as functionally. In addition to the ciliated sensilla along the upper lip, structures consisting of a short, club-like process surrounded by granular material were observed inside the mouth. These structures may also be chemosensory organs.
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  • 98
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    Journal of Morphology 192 (1987), S. 193-204 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The architecture and fine structure of the epigastric hematopoietic nodules of the ridgeback prawn, Sicyonia ingentis, are described. The nodules consist of a highly branched series of tubules that contain the maturing hemocytes within a connective tissue stroma. Hemocytes can exit the hematopoietic nodules by penetrating through fenestrations in the endothelial cell layer into the central hemal space or by migrating through the outer later of capsular cells and associated collagen fibrils. Four hemocyte categories were observed: agranular, small granule with cytoplasmic deposits, small granule without cytoplasmic deposits, and large granule hemocytes. This classification was based upon the presence, size, and type of cytoplasmic granules and the presence of cytoplasmic deposits. Only agranular cells and small granule hemocytes without cytoplasmic deposits appeared capable of division. Intermediate stages were observed between agranular hemocytes and small granule hemocytes with deposits and between small granule hemocytes without deposits and large granule hemocytes, suggesting existence of two distinct hemocyte lines.
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  • 99
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    Journal of Morphology 192 (1987), S. 247-256 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This investigation is a light and electron microscopic description of the submandibular duct salivary bladder of the rat, a dilation of the distal end of the main excretory duct. The wall of the bladder consists of (1) a mucosa with pseudostratified epithelium, (2) a submucosal layer of connective tissue, and (3) an underlying layer of striated muscle. The pseudostratified columnar epithelium lining the bladder is composed of three cell types: (1) light cells, (2) dark cells, and (3) basal cells. The lamina propria contains bundles of collagen, attenuated fibrocytes, capillaries with fenestrated endothelia, and nerve fibers which enter the epithelial layer. The capillaries of the submucosa are not fenestrated. The morphology of the wall of this structure provides evidence that the primary fluid of the submandibular gland is modified in the bladder by transepithelial fluid and ion transport.
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 257-268 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The innervation and structure of the lung of the Australian snake-necked tortoise, Chelodina longicollis, was examined by using light microscopy including fluorescence histochemical techniques. The anterior lung was divided into a number of compartments with numerous alveolar spaces. The posterior lung was simpler and saclike in structure and alveolar spaces were absent. Smooth muscle fibers occurred in discrete muscle bands and in the walls of the septal bands. Ganglion cells occurred along nerve trunks throughout the lung but were more numerous in the posterior lung. Smooth muscle bands, the extrinsic pulmonary artery, and the arteries within the lung were sparsely innervated by adrenergic fibers. Substance P-containing sensory fibers were not demonstrated. The innervation and structure of the lung are compared to published work on other reptiles.
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