Search results
Results from the WOW.Com Content Network
The density of the water prevents the gills from collapsing and lying on top of each other, which is what happens when a fish is taken out of water." [7] Higher vertebrates do not develop gills, the gill arches form during fetal development, and lay the basis of essential structures such as jaws, the thyroid gland, the larynx, the columella ...
The gills' large surface area tends to create a problem for fish that seek to regulate the osmolarity of their internal fluids. Saltwater is less dilute than these internal fluids, so saltwater fish lose large quantities of water osmotically through their gills. To regain the water, they drink large amounts of seawater and excrete the salt.
The density of the water prevents the gills from collapsing and lying on top of each other; [such collapse] happens when a fish is taken out of water." [ 4 ] Usually water is moved across the gills in one direction by the current, by the motion of the animal through the water, by the beating of cilia or other appendages, or by means of a ...
In osteichthyes, the gills contain 4 gill arches on each side of the head, two on each side for chondrichthyes or seven gill baskets on each side of the fish's head in lampreys. In fish, the long bony cover for the gill (the operculum) can be used for pushing water. Some fish pump water using the operculum.
Aquatic animals generally conduct gas exchange in water by extracting dissolved oxygen via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are evolved from terrestrial ancestors that re-adapted to aquatic environments (e.g. marine reptiles and marine mammals), in which case they actually ...
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 ...
In most other gastropods, the right gill has been lost. In groups such as the turban shells the gill still retains its primitive bipectinate form, and in these animals, the water current is oblique, entering the mantle cavity on the left side of the head, flowing over the gill, and then being flushed out on the right side. The anus is also on ...
In fish, gill lamellae are used to increase the surface area in contact with the environment to maximize gas exchange (both to attain oxygen and to expel carbon dioxide) between the water and the blood. [3] In fish gills, there are two types of lamellae, primary and secondary. The primary gill lamellae (also called gill filament) extends from ...