Question

(A) why is sino atrial node (SAN) called as pacemaker of our heart? where is SAN locate?
(B)explain the mechanism through which a sound produces a nerve impulse in the in the inner ear

Answer 1

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.