Search results
Results from the WOW.Com Content Network
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.
The gill arches of bony fish typically have no septum, so that the gills alone project from the arch, supported by individual gill rays. Some species retain gill rakers . Though all but the most primitive bony fish lack a spiracle, the pseudobranch associated with it often remains, being located at the base of the operculum.
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.
External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits, as they are in most fishes. Instead, the respiratory organs are set on a frill of stalks protruding from the sides of an animal's head. The axolotl has three pairs of external ...
The thoracic section of the body has 3 or 4 segments with paddle-like capillary bristles. The abdominal section has many segments each with hooked bristles on raised lobes. There are a pair of gills on each of the thoracic segments and on the front abdominal segments. The rear of the body is bent forward along a groove in the midsection of the ...
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In contrast, bony fishes have a single outer bony gill covering called an operculum.
In fish gills, there are two types of lamellae, primary and secondary. The primary gill lamellae (also called gill filament) extends from the gill arch, and the secondary gill lamellae extends from the primary gill lamellae. Gas exchange primarily occurs at the secondary gill lamellae, where the tissue is notably only one cell layer thick.
Gill openings: Usually five pairs of gill slits which are not protected by an operculum. Five pairs of gill slits protected by an operculum (a lateral flap of skin). Type of gills: Larnellibranch with long interbranchial septum: Filiform with reduced interbranchial septum Spiracles: The first gill slit usually becomes spiracles opening behind ...