Question

Write any four differences between S.A. Node and A.V. Node

Answer 1

Hint: S.A. (Sino atrial node) and A.V. (atrioventricular nodes) both are the important elements of the cardiac conduction system but have different functions. S.A. node is responsible for sending out electrical impulse into atria which makes atria contract while A.V. The node carries electrical impulse to ventricles which allow the heart chamber to contract. After their contraction, each part of the cardiac system reset electrically. By this means they complete their one cycle and then again repeat the same process.

Complete answer:
The major differences between S.A. Node and A.V. Node area as following:

SA node (Sinoatrial node)	AV node (Atrioventricular node)
It is present in the right atrium near the opening of superior vena cava.	It is present in the right atrium at the base of inter atrial septum or we can say near the opening of the coronary sinus.
SA node is larger in size as compared to AV node.	AV node is smaller in size as compared to SA node.
It has maximum rhythmicity.	It has less rhythmicity than SA node.
SA node is also known as pacemaker.	AV nodes are also known as pacesetters.
Function Regulated by cardiac centre.	Function stipulated by cardiac impulses.
Firing rate is 60-100 bpm.	Firing rate is 40-60 bpm.

Note: Sino atrial node and atrioventricular node are a group of cells responsible for contraction for heart chambers. The main function of SA is to generate cardiac impulse while AV nodes relay the response given by SA (Sino atrial) node or we can say that the action of AV (Atrioventricular) nodes are controlled by the impulse generated by Sino atrial nodes.