ISSN:
0362-2525
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The lungs of the New Caldeonian gecko Rhacodactylus leachianus were examined by means of gross dissection and light and electron microscopy. This tropical species, which is the largest living gecko, possesses two simple, single-chambered lungs. Right and left lungs are of similar size and shape. The lung volume (27.2 ml · 100 g-1) is similar to that of the tokay (Gekko gecko) but differs in that the gas exchange tissue is approximately homogeneously distributed, and the parenchymal units (ediculae) are very large, ∼2 mm in diameter. The parenchymal depth varies according to the location in the lung, being deepest near the middle of the lung and shallowest caudally. Scanning and transmission electron microscopy reveal an unusual distribution of ciliated cells in patches on the edicular walls as well as on the trabeculae. Secretory cell are very numerous, particularly in the bronchial epithelium, where they greatly outnumber the ciliated cells. The secretory cells form a morphological continuum characterized by small secretory droplets apically and large vacuoles basally. This continuum includes cells resembling type II pneumocytes but which are devoid of lamellar bodies. Type I pneumocytes similar to those of other reptiles cover the respiratory capillaries, where they form a thin, air-blood barrier together with the capillary endothelial cells and the fused basement laminae. The innervation, musculature, and vascular distribution in R. leachianus are also characterized. Apparent simplification of the lungs in this taxon may be related to features of its sluggish habits, whereas peculiarities of cell tissue composition may reflect demands of its mesic habitat.
Additional Material:
18 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jmor.1051990104
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