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sinus node
noun
: a small mass of tissue that is embedded in the musculature of the right atrium of higher vertebrates and that originates the impulses stimulating the heartbeat
Examples of sinus node in a Sentence
Recent Examples on the Web
An electrical impulse is sent from the sinus node in the region at the top of the heart down through the bottom to make the heart muscle contract.
—Julie Scott, Msn, Anp-Bc, Aocnp, Verywell Health, 23 Oct. 2024
This indicates the sinus node is not working properly.
—Angela Ryan Lee, Verywell Health, 25 Sep. 2024
Normally, specialized cells called the sinus node in the heart's upper right chamber give a rhythmic signal for the heart to contract.
—Christopher Lee, Verywell Health, 22 July 2024
Hearts beat when the sinus node, a small mass of tissue in the right upper chamber, transmits an impulse to the heart cells.
—Michael Ciaglo, National Geographic, 5 June 2020
Over the course of a day, a person’s heart beats about 100,000 times, and each beat begins with an electrical signal generated in the sinus node in the heart’s upper right chamber.
—Emily Sohn, Washington Post, 7 Mar. 2018
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Word History
First Known Use
1937, in the meaning defined above
Dictionary Entries Near sinus node
Cite this Entry
“Sinus node.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sinus%20node. Accessed 14 Nov. 2024.
Medical Definition
sinus node
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