The ultrastructure of ependymal cells of the median eminence in young Pacific blacktip reef sharks is described. Three major cell types have been observed. The first type is an irregularly‐shaped, electron dense cell with many long microvilli and occasional cilia projecting into the ventricle. A second type contains dense cytoplasmic granules in sizes ranging from 1000–2000 Å, and may be morphologically equivalent to “liquor‐contacting neurons” observed in ependymal linings elsewhere. The third type appears very similar to crown cells of saccus vasculosus of this and other species. Cells of the third type possess large, lipid‐like inclusions, bulbous projections originating from basal bodies, and prominent smooth endoplasmic reticulum. The crown‐like cells are compared to cells of saccus vasculosus of young and adult sharks, and their possible significance is discussed.
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)