Question

Frog's heart when taken out of the body continues to beat for some time. Select the best option from the following statement.
(a)Frog is a poikilotherm.
(b)Frog does not have any coronary circulation.
(c)Heart is "myogenic" in nature.
(d)Heart is autoexcitable.
A.(c) and (d)
B.only (c)
C.only (d)
D.(a) and (b)

Answer 1

Hint: 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 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.
2)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.

Statement A: The frog is a poikilotherm which means it can change the body temperature according to the surrounding temperature. This feature of the frog is not related to the heart of a frog. Therefore, this is the incorrect statement.

Statement B: Coronary circulation is blood circulation in blood vessels that supplies blood to the heart muscles, After taking out the frog's heart, blood flow is not possible as the blood vessels get disconnected from the heart. Therefore, this is the incorrect statement.

Statement C: The heart of the frog beats due to stimulation of the sinoatrial node present in the right auricle due to which the heart can beat for some time even after it is removed from the body. Therefore, this is the correct statement.

Statement D: The heart of the frog can excite by itself and it does not need a nervous system to excite, Hence the heart of the frog is autoexcitable. Due to this feature, the heart of the frog can beat even after the removal of the heart from the frog's body. Therefore, this is the correct statement.

Hence, the correct answer is option (A)

Note: 1)The vascular system of the frog is very well developed and the frogs show closed circulation.
2)The heart in the frog is situated on the upper part of the frog's body where a structure known as sinuous venous is attached to the right auricle.