The blood system of amphibious animals (frogs, tritons, salamanders, chervyag) considerably differs from that at reptiles (snakes, turtles, crocodiles, lizards) and Crustacea (crayfish). Amphibia are an intermediate link between Crustacea and reptiles.
Blood system of Amphibia
At amphibious animals the blood system is closed. Only lungless salamanders possess the heart consisting of two cameras. All other amphibians have three-chambered heart. The blood system of representatives of this class of animals consists of two circles of blood circulation – small and big. It is curious that the small circle of blood circulation resulted from emergence in these animals of pulmonary breath. Heart at Amphibia consists of two auricles and one ventricle.
Blood at these animals in different auricles different: in right it mixed (venous is more), and in left – arterial. Amphibia possess also a number of the arteries which are responsible for blood transfer: for example, skin and pulmonary arteries transfer blue blood to skin and to lungs, and sleepy - supply with arterial blood an upper body (for example, in the head). Arches of an aorta are designed to transport the mixed blood to all other bodies of Amphibia. It should be noted that body temperature at amphibians is the changeable size depending on ambient temperature Amphibia there are cold blooded animals.
Blood system of reptiles
The blood system of reptiles is similar to that at Amphibia, but has also the differences. Heart of reptiles consists of two auricles opening in a ventricle. At all reptiles, except crocodiles, the ventricle is divided by an incomplete partition. It allows their blood arriving from auricles to mix up partially. The pulmonary artery and two arches of an aorta independently begin in a warm ventricle and connect in a back aorta, at the same time the arteries departing from it supply with the mixed blood other body organs of reptiles. Such organization of blood supply allows this animals to be the most adapted for any given living conditions.
Blood system of Crustacea
At Crustacea the blood system is not closed. It also distinguishes them from two other above-mentioned animal classes. If to compare the blood system of Crustacea to that at reptiles and amphibians, then at the first it is the most primitive. Blood is set in motion by means of the heart beat placed near gills. Only the highest Crustacea possess blood vessels. At all other representatives of this trivial group of animals blood freely flows on the cavities close to internals. Quite often in such blood special respiratory pigments are dissolved.