Atrioventricular node

Atrioventricular node

Infobox Anatomy
Name = PAGENAME
Latin = nodus atrioventricularis
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Caption = AV node visible near bend of red line.


Caption2 = Heart; conduction system
Precursor =
System =
Artery = atrioventricular nodal branch
Vein =
Nerve =
Lymph =
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DorlandsPre = n_09
DorlandsSuf = 12576113
The atrioventricular node (abbreviated AV node) is an area of specialized tissue between the atria and the ventricles of the heart, specifically in the posteroinferior region of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles.

The AV node may also be (rarely) referred to as the "Aschoff-Tawara node". [WhoNamedIt|synd|454]

Function

The AV node receives two inputs from the atria: posteriorly via the crista terminalis, and anteriorly via the interatrial septum. [ACC/AHA/ESC Guidelines for the Management of Patients with Atrial Fibrillation - Executive Summary ( [http://www.acc.org/clinical/guidelines/atrial_fib/exec_summ/exec_afindex.htm Full text] )]

An important property that is unique to the AV node is "decremental conduction", in which the more frequently the node is stimulated, the slower it conducts. This is the property of the AV node that prevents rapid conduction to the ventricle in cases of rapid atrial rhythms, such as atrial fibrillation or atrial flutter.

The atrioventricular node delays impulses for a while (aprox. 0.16s) before allowing impulses through to the His-Purkinje conduction system, which spreads impulses to the ventricular walls. The reason it is important to delay the cardiac impulse is to ensure that the atria have ejected their blood into the ventricles before the ventricles contract. [Campbell, N., & Reece, J. (2002). Biology. 6th ed. San Francisco: Benjamin Cummings.]

The AV node is located between the right atrium and right ventricle. It slows the signals and allows the ventricles to fill before it moves on.

Blood supply

The blood supply of the AV node is from the posterior interventricular artery. When the RCA supplies the posterior descending artery and thus the AV node, the coronary system is said to be "right dominant," and when the posterior descending artery is supplied by the LCX, the system is "left dominant."

ee also

*Electrical conduction system of the heart
*Sinoatrial node (SA node)

References

External links

* - "The conduction system of the heart."
* (NormanAnatomyFig|thoraxheartinternalner)
* http://www.healthyheart.nhs.uk/heart_works/heart03.shtml


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Look at other dictionaries:

  • atrioventricular node — noun a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle • Hypernyms: ↑cardiac muscle, ↑heart muscle * * * noun : a small mass …   Useful english dictionary

  • Atrioventricular node — The atrioventricular (AV) node is an electrical relay station between the atria (the upper) and the ventricles (the lower chambers of the heart). Electrical signals from the atria must pass through the AV node to reach the ventricles. The AV node …   Medical dictionary

  • atrioventricular node — Anat. a small mass of muscular fibers at the base of the wall between the atria, conducting impulses received from the sinoatrial node by way of the atrioventricular bundles and, under certain conditions, functioning for the sinoatrial node as… …   Universalium

  • atrioventricular node — AV node a mass of modified heart muscle situated in the lower middle part of the right atrium. It receives the impulse to contract from the sinoatrial node, via the atria, and transmits it through the atrioventricular bundle to the ventricles …   The new mediacal dictionary

  • atrioventricular node — noun Date: circa 1934 a small mass of tissue in the right atrioventricular region of higher vertebrates through which impulses from the sinoatrial node are passed to the ventricles …   New Collegiate Dictionary

  • atrioventricular node — a′trioventric′ular node n. anat. a small mass of conducting muscle fibers in the heart, at the base of the right atrium, that transmits heartbeat impulses to the ventricles • Etymology: 1930–35 …   From formal English to slang

  • atrioventricular node — /ætrioʊvɛnˌtrɪkjələ ˈnoʊd/ (say atreeohven.trikyuhluh nohd) noun a mass of specialised conductive tissue in the heart, which transmits electrical impulses to initiate contraction; A V node …  

  • Atrioventricular — (having to do with an atrium and ventricle) can refer to: *Left atrioventricular opening *Atrioventricular fistula *Atrioventricular node *The term Atrioventricular valves is used to describe the mitral valve and tricuspid valve …   Wikipedia

  • atrioventricular bundle — n BUNDLE OF HIS * * * (AV bundle, bundle of His) a bundle of modified heart muscle fibres (Purkinje fibres) passing from the atrioventricular node forward to the septum between the ventricles, where it divides into right and left bundles, one for …   Medical dictionary

  • Node — Literally a knot, a node is a collection of tissue. For example a lymph node, is a collection of lymphoid tissue. A nodule is a small node, a little collection of tissue. * * * 1. A knob or nodosity; a circumscribed swelling; in anatomy, a… …   Medical dictionary

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