Question

Pacemaker is situated in the
(A) Wall of right atrium
(B) Interauricular septum
(C) Interventricular septum
(D) wall of left atrium

Answer 1

Hint: A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.

Complete answer:
The sinus node (SA) continuously generated electrical impulses, thereby setting the normal rhythm and rate in a healthy heart. Hence, the SA node is referred to as the natural pacemaker of the heart.
The contraction of cardiac muscle (heart muscle) in all animals is initiated by electrical impulses known as action potentials. The rate at which these impulses fire, controls the rate of Cardiac contraction, that is, heart rate. The cells that create these rhythmic impulses, setting the face for blood pumping, are called pacemaker cells, and they directly control the heart rate. They make up the cardiac pacemaker, that is, the natural pacemaker of the heart. The concentration of pacemaker cells in the Sinoatrial (SA) node is the natural pacemaker, and the resultant rhythm is a sinus rhythm.
Pacemaker is a Sinoatrial on SA node situated in the upper corner of all right atrium in the heart. Initiates and maintains the rhythmic contraction of the heart. Excitation waves begin in SA nodes due to which atria contract and the oxygenated and deoxygenated blood is forced into respective ventricles through atrioventricular valves. It acts as a stimulus for the next wave of excitation and thus maintains the frequency of heartbeat.

So, the correct answer is option A i.e,‘In the wall of the right atrium’.

Note:Sometimes an ectopic pacemaker sets the face, if the SA node is damaged or if the electrical conduction system of the heart has problems. Cardiac arrhythmia can cause heart block, in which the contraction loses any useful rhythm. In humans, a mechanical device called an artificial pacemaker is used after damage to the body's intrinsic conduction system to produce these impulses synthetically.