4 Answers
The sino-atrial (SA) node is a specialised bundle of neurons located in the upper part of the right atrium of the heart. The cardiac impulse originating from the SA node triggers a sequence of electrical events in the heart, thereby controlling the sequence of muscle contraction that pumps blood out of the heart. Since the SA node initiates and maintains the rhythmicity of the heart, it is known as the natural pacemaker of the human body.
The SA Node is responsible for initiating and maintaining the rhythmic contractile activity or beating of the heart. Due to this, the SA Node is called the pacemaker.
In human heart, Sino atrial node initiates the conduction of heart beat. The excitory wave of SA node is called cardiac impulse and it determines the rate of heart beat and sets the pace of the activities of the heart. Hence Sino atrial node is termed as pacemaker of the heart.
Sino-atrial node is a bundle of nerves which initiates the conduction of heartbeat. So, this is also called the pacemaker of our heart.