sinoatrial node


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Related to sinoatrial node: atrioventricular node, bundle of His

sinoatrial node

n.
A small mass of specialized cardiac muscle fibers located in the posterior wall of the right atrium of the heart that acts as a pacemaker by generating at regular intervals the electric impulses of the heartbeat. Also called sinoauricular node, sinus node.

si′no•a′tri•al node′

(ˈsaɪ noʊˈeɪ tri əl, ˌsaɪ-)

n.
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.
[1920–25; sin (us) + -o- + atrial]

sinoatrial node

(or SA node) Special cells in the heart wall, forming its natural pacemaker.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.sinoatrial node - a specialized bit of heart tissue that controls the heartbeat
cardiac muscle, heart muscle - the muscle tissue of the heart; adapted to continued rhythmic contraction
References in periodicals archive ?
Caption: The sinoatrial node (circled above) in your heart sends out electrical impulses that cause your heart to beat.
The artery of the sinoatrial node, anatomic considerations based on 45 injectiondissections of the heart.
For example, researchers need to better understand the mechanisms controlling the development and maintenance of pacemaker cells in the sinoatrial node, just as they must develop ways to compare experimental biological pacemaker tissue with bona fide sinoatrial node tissue.
The AV dissociation is separated into 2 subtypes: 1) the atria and ventricles beat independent of each other under the control of separate pacemaker foci, and 2) impulses from the sinoatrial node can occasionally be conducted to the ventricle during AV dissociation, causing ventricular capture and ventricular fusion complexes, termed as complete and incomplete AV dissociation, respectively.
The HF component measures the influence of the vagus nerve in modulating the sinoatrial node, whereas the LF component provides an index of sympathetic effects on the heart, and the LF/HF ratio indicates sympathovagal balance.
The sinoatrial node has a natural frequency of about 90 beats per min.
Called the sinoatrial node, it acts like a metronome to keep the heart pulsing at 60 to 100 beats a minute or so, more when you're active.
The heart's pacemaker, the sinoatrial node, regulates the timing of the phases by sending electrical impulses to the atria and ventricles.
Viewpoint: Is the resting bradycardia in athletes the result of remodeling of the sinoatrial node rather than high vagal tone?