A comparative study of the structures of hearts of vertebrates reveals that there is an evolutionary change in the pattern of heart among the vertebrates. All of the vertebrates possess a muscular chambered heart. The fishes have a 2-chambered heart; with an atrium and a ventricle, which then evolved into the three-chambered heart in amphibians and reptiles which have two atria and one ventricle. In this type of heart, both the pureblood and impure blood get mixed in the ventricle. In case of higher animals like aves, reptiles, and mammals, the heart further evolved out as a well-developed, 4-chambered structure with two atrium and two ventricles. All these groups of animals exhibit double circulation and hence there is no mixing of oxygenated and deoxygenated blood.
Answered by Pragya Singh | 1 year agoDraw a standard ECG and explain the different segments in it.
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