sinoatrial node n.
A small mass of specialized cardiac muscle fibers located in the posterior wall of the right atrium of the heart that acts as a pacemaker of the cardiac conduction system by generating at regular intervals the electric impulses of the heartbeat. Also called sinoauricular node, sinus node.
|sinoatrial node (sī'nō-ā'trē-əl) Pronunciation Key
A small mass of specialized cardiac muscle fibers that acts as a pacemaker by initiating and maintaining normal heartbeat and cardiac rhythm. It is located in the right atrium.