Assertion: Sino-atrial node (SAN) is called the pacemaker. Reason: SAN generates the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractions of the heart

Question

Assertion: Sino-atrial node (SAN) is called the pacemaker. Reason: SAN generates the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractions of the heart (A) If both assertion and reason are true and reason is the correct explanation of assertion (B) If both assertion and reason are true but reason is not the correct explanation of assertion (C) If assertion is true but reason is false (D) If both assertion and reason are false

Tardigrade Admin · Accepted Answer

In the myogenic heart, contraction is initiated by specialised muscles. The SAN can generate the maximum number of action potentials, i.e., 70-75 min-1, and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. The SAN controls the beat of the heart because its rate of rhythmical discharge is faster than that of any other part of the heart. Therefore, the SAN is virtually always the pacemaker of the normal heart.

Q. Assertion : Sino-atrial node (SAN) is called the pacemaker. Reason : SAN generates the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractions of the heart

If both assertion and reason are true and reason is the correct explanation of assertion

If both assertion and reason are true but reason is not the correct explanation of assertion

If assertion is true but reason is false

If both assertion and reason are false

Q. Assertion : Sino-atrial node $(S A N)$ is called the pacemaker.
Reason : $S A N$ generates the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractions of the heart