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sinoatrial node Syllabification: si·no·a·tri·al node
Pronunciation: /ˌsīnōˌātrēəl ˈnōd/

Definition of sinoatrial node in English:


A small body of specialized muscle tissue in the wall of the right atrium of the heart that acts as a pacemaker by producing a contractile signal at regular intervals.
Example sentences
  • This activity arises not from excitatory nerve fibres, but spontaneously within the heart itself from a small clump of pacemaker cells near the point where the vena cava joins the right atrium: the sino-atrial node.
  • The classical concept of the source of cardiac rhythm is that it originates from the sino-atrial node.
  • Procoralan exclusively reduces heart rate by a specific action on the sino-atrial node.


Early 20th century: from sinus + atrial (see atrium).

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