Meaning of sinoatrial node

si'no•a'tri•al node'

Pronunciation: (sī'nō-ā'trē-ul, sī"-), [key]
— Anat. Anat.
  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. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.