Definition of sinoatrial node
First Known Use of sinoatrial node
Medical Definition of 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
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Britannica.com: Encyclopedia article about sinoatrial node
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