sinoatrial node

sinoatrial node
= SA node
the pacemaker of the heart: a microscopic area of specialized cardiac muscle located in the upper wall of the right atrium near the entry of the vena cava. Fibres of the SA node are self-excitatory, contracting rhythmically at around 70 times per minute. Following each contraction, the impulse spreads throughout the atrial muscle and into fibres connecting the SA node with the atrioventricular node. The SA node is supplied by fibres of the autonomic nervous system; impulses arriving at the node accelerate or decrease the heart rate.

The new mediacal dictionary. 2014.

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  • sinoatrial node — [sī΄nōô rik′yə lərsī΄nō ā′trē əl] n. PACEMAKER (sense 2a): sometimes called sinoauricular node [sī΄nōô rik′yə lər] …   English World dictionary

  • Sinoatrial node — Infobox Anatomy Name = Sinoatrial or (el) node Latin = nodus sinuatrialis GraySubject = GrayPage = Caption = Interior of right side of heart. (SA node not labeled, but region visible at left, near crista terminalis. Caption2 = Schematic… …   Wikipedia

  • Sinoatrial node — The sinoatrial node (the SA node) is one of the major elements in the cardiac conduction system, the system that controls the heart rate. This stunningly designed system generates electrical impulses and conducts them throughout the muscle of the …   Medical dictionary

  • sinoatrial node — noun Date: 1913 sinus node …   New Collegiate Dictionary

  • sinoatrial node — /suy noh ay tree euhl, suy /, Anat. 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. Also called sinus node. [1920 25; SINO + ATRIAL] * * * …   Universalium

  • sinoatrial node — si′no•a′tri•al node′ [[t]ˈsaɪ noʊˈeɪ tri əl, ˌsaɪ [/t]] n. anat. 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 • Etymology: 1920–25; sin… …   From formal English to slang

  • sinoatrial node — noun a specialized bit of heart tissue that controls the heartbeat • Syn: ↑pacemaker, ↑cardiac pacemaker, ↑SA node • Hypernyms: ↑cardiac muscle, ↑heart muscle …   Useful english dictionary

  • sinoatrial node — [ˌsʌɪnəʊ eɪtrɪəl] noun Anatomy a small body of specialized muscle tissue in the wall of the heart whose contractions regulate the heartbeat. Origin early 20th cent.: from sinus + atrial (see atrium) …   English new terms dictionary

  • Sinoatrial arrest — or sinus arrest is a medical condition wherin the sinoatrial node of the heart transiently ceases to generate the electrical impulses that normally stimulate the myocardial tissues to contract and thus the heart to beat. Since the heart contains… …   Wikipedia

  • sinoatrial block — sinoatrial exit block a disturbance in which the atrial response is delayed or omitted because of partial or complete interference with the propagation of impulses from the sinoatrial node to the atria …   Medical dictionary

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