ISSN:
1432-0878
Keywords:
Gills
;
Respiratory epithelia
;
Fishes
;
Microvilli
;
Mucus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The ultrastructure of the secondary lamellae has been examined in four species of free-swimming elasmobranchs, two species of Raia and five species of bony flatfishes. Microvilli which are present on the outer epithelial surface vary in form and size. It is suggested that a possible function of the microvilli is to anchor a surface mucus covering whose possible functions are discussed. Vesicles are found immediately beneath the microvilli in elasmobranchs but not in teleosts. Chloride and mucous cells are present on the secondary lamellae of all species and often have microvilli of greater length than on the other cells of the epithelium. Micropinocytotic vesicles are found on both sides of the basement membrane. The number of columns enclosed in the pillar cells varied from 5–11. The water-blood pathway showed variations in thickness not only between different species but also in different parts of individual secondary lamellae. A general trend in the mean total thickness was found, being greater in the swimming elasmobranchs (10.22 μ) than in the rays (5.47 μ) and bony flatfish (3.59 μ). This trend is also seen in the greater length of microvilli and thickness of basement membrane in the elasmobranchs than in the teleosts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00335372
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