sinoatrial node


Example Sentences

Recent Examples on the Web Of the billions of cells in the human heart, a mere 10,000 pacemaker cells---collectively called the sinoatrial node---are responsible for sending the electrical pulse through the remaining heart cells. Breanna Draxler, Discover Magazine, 19 Dec. 2012

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sinoatrial node.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1913, in the meaning defined above

Time Traveler
The first known use of sinoatrial node was in 1913

Dictionary Entries Near sinoatrial node

Cite this Entry

“Sinoatrial node.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2023.

Medical Definition

sinoatrial node

: a small mass of tissue that is made up of Purkinje fibers, ganglion cells, and nerve fibers, that is embedded in the musculature of the right atrium of higher vertebrates, and that originates the impulses stimulating the heartbeat

called also S-A node, sinus node

More from Merriam-Webster on sinoatrial node

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