sinoatrial node

[sahy-noh-ey-tree-uhl, sahy-]

noun

Anatomy.

1. a small mass of tissue in the right atrium functioning as pacemaker of the heart by giving rise to the electric impulses that initiate heart contractions.

sinoatrial node

1. 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.

Word History and Origins

Origin of sinoatrial node¹

1920–25; sino- + atrial ( def. )