sinoatrial node

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

  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.

Origin of sinoatrial node

1920–25; sino- + atrial

Words Nearby sinoatrial node Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Scientific definitions for sinoatrial node

sinoatrial node

[ sī′nō-ātrē-əl ]

  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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.