Question

When heart of frog is cut, it will
A.Not beat at all
B.Stop beating soon after
C.Continue to beat for a long time if kept dry
D.Continue to beat for a long time if kept moist

Answer 1

The heart of a frog is a three-chambered heart with two atria and one ventricle and the other features of the frog's heart are almost similar to that of other vertebrates.

Complete answer:
1)The respiratory system of the frog includes the skin surface and lining of the mouth along with the lungs.
2)_The frog can also use its skin for the exchange of respiratory gases, Hence even when the heart of the frog is cut it will still beat for some time if the frog is kept moist because the skin of the frog can absorb oxygen from the water through specialized glands due to which exchange of gas takes place in frog even after cutting the heart.
3)The heartbeat in frogs does not require any external stimulus as it can generate the heartbeat within the heart itself with the help of the sino-auricular node so it can easily generate a heartbeat after receiving oxygen through the skin.
4)The heartbeat of the frog does not depend on the nervous system of the frog, Hence the heart of the frog is known as the Myogenic heart.

Option D: Since the heart of the frog is myogenic and is not dependent on the nervous system the heart of the frog can beat by absorbing oxygen through the skin only if the skin of the frog is kept moist and will stop beating if the skin is dry. Therefore, this is the correct option.

Hence, the correct answer is option (D)

Note: The skin of the frog contains mucous glands that secrete mucus due to which the frog can easily respire through its skin. The respiration or gaseous exchange that occurs through the skin is termed cutaneous respiration. The vascular system of the frog is very well developed and the frog shows closed circulation.