The circulatory system of amphibians.

Amphibians are also called amphibians. Their most common representatives are frogs. There is a wide variety of them. They have a fairly developed circulatory system. It consists of the heart and blood vessels. Frogs have three chambers in their hearts. The vessels form two circles of blood circulation – large and small. As in a person, in a small circle, the blood is saturated with oxygen. In addition to lungs, frogs are able to breathe over the entire surface of their skin. When they are immersed in water, they can use up the air in their lungs for a long time.