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During ventilation, water is taken into the oral cavity, forced past protective gill rakers, over the the gills, and into the opercular chamber, before exiting via the external gill slit.
Gills are arranged as a stack of V-shaped pairs of cartilaginous 1° lamellae branching off each branchial arch. Each 1° lamella has 2° lamellae projecting from the dorsal surface, covered by a mucous producing surface epithelium and containing vascular capillaries lined by pillar and chloride cells. Diffusion of gases occurs across the 2° lamellae.
The vascular supply to the gills is via the afferent branchial arteries, which divide into smaller vessels supplying each arch and 1° lamella. The efferent branchial ateries then carry oxygenated blood to other vessels supplying the rest of the body. |
