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. )

Example Sentences

A heartbeat begins when the organ’s pacemaker, a structure called the sinoatrial node, fires off an electrical impulse that disperses across the atria, the blood-collecting chambers.

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TBX18 is normally active in embryos, where it triggers, among other things, the formation of the heart’s rhythm keeping centre, the sinoatrial node.

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In healthy people, a small region of the heart, called the sinoatrial node, fires the electrical impulses that determine heart rate.

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In 12 pigs, the team mimicked a fatal human heart condition in which electrical activity cannot spread through the heart from the sinoatrial node, forcing other, weaker parts of the heart to take over.

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Instead, she went on about P waves and the sinoatrial node and what my mom’s EKG looked like, all at lightning speed.

Read more on Time