Question

Rate of heart beat is determined by

• A. Purkinje fibres
• B. papillary muscles
• C. AV-node
• D. SA-node.

Answer 1

The Correct Option is D

SA nodes can act as the normal pacemaker and is used to determine the rate of heartbeat. It helps in the regulation of the heartbeat with the help of the action potential that is generated. n depolarization heart muscles contract and therefore pumping of the blood. SA nodes have the highest depolarization rate because their cells have the ability to automaticity.  As the pacemaker cells create these rhythmical impulse therefore an artificial pacemaker is implanted at the site of SA node to mimic the actions of the node and conducting system and helps to regulate heartbeat.

Answer 2

Ans. The human heartbeat rate can be understood by the following points:

• The human heart has two auricles and two ventricles, making it four-chambered.
• Different kinds of valves govern and control how each chamber opens and closes.
• The top posterior wall of the right atrium has a cell mass known as the SA node (Sino-atrial node).
• Because it produces electrical impulses, the heart is referred to as its pacemaker.
• The heart's walls constrict as a result of these electrical impulses traveling through them.
• Blood is transferred from the auricles to the ventricles as a result of this contraction. 
• Because of this, we say that the SA node controls the heart's rhythm and beat rate.
• The auricles and verticals are electrically connected by another mass known as the AV node.
• The ventricular walls receive the electrical impulses produced by the SA node from the Purkinje fibers.
• Atrioventricular valves are opened and closed with the assistance of papillary muscles.
• The rate at which the entire heart beats is determined by the electrical impulses that are sent out by the cells of the SA node at a certain frequency.

One of the key components of the cardiac conduction system, which regulates heart pace, is the SA node (SA stands for sinoatrial).

Location:

The right atrium, or right upper chamber of the heart, has a cluster of cells called the SA node in its upper portion. The exact location is the right upper auricular wall.

Function:

It starts the heartbeat by starting electric impulses. The SA node is where the electrical impulses are produced. The sinus node is another name for the SA node.

The atrioventricular node (AV node), which receives the electrical signal produced by the SA node, is reached after traveling through the heart's cells.