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In contrast, bony fishes have a single outer bony gill covering called an operculum. Most sharks and rays have five pairs of gill slits, but a few species have 6 or 7 pairs. Shark gill slits lie in a row behind the head. The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow.
Shark Anatomy (50693674756) The gill slits of a whale shark flaring as it expels water from its pharyngeal cavity. In the shark anatomy image, it depicts the beginning half of the shark, including the gills. The shark gills are especially important and were evolved from the chordate pharyngeal gill slits synapomorphy.
The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange. [5] When a fish breathes, it draws in a mouthful of water at regular intervals. Then it draws the sides of its throat together, forcing the water through the gill openings, so it passes over the gills to the outside.
Gill arches supporting the gills in a pike. Branchial arches or gill arches are a series of paired bony/cartilaginous "loops" behind the throat (pharyngeal cavity) of fish, which support the fish gills. As chordates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa.
Stories tell of men with shark jaws on their back who could change between shark and human form. A common theme was that a shark-man would warn beach-goers of sharks in the waters. The beach-goers would laugh and ignore the warnings and get eaten by the shark-man who warned them. Hawaiian mythology also includes many shark gods.
In 99 percent of encounters between sharks and humans, nothing happens. Here are some easy-to-remember tips for that terrifying one percent. Aim for the gills, and 6 other tips that could save ...
Batoid gill slits lie under the pectoral fins on the underside, whereas a shark's are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the guitarfishes and sawfishes , while most sharks have a spindle-shaped body.
Humans Are One Step Closer to Regenerating Limbs Getty Images. Blastema cells in deer grow into bone and antler cartilage, holding the key to possible bone regrowth in humans.