Atrioventricular node - wikipedia Atrioventricular node Atrioventricular node Image showing the conduction system of the heart. The AV node is labelled 2. Details System Electrical conduction system of the heart Artery Atrioventricular nodal branch Identifiers Latin Nodus atrioventricularis Acronym ( s ) AV node Dorlands / Elsevier n_09 / 12576113 TA A12. 1.06. 004 FMA 9478 Anatomical terminology ( edit on Wikidata ) The atrioventricular node, or AV node is a part of the electrical conduction system of the heart that coordinates the top of the heart. It electrically connects the right atrium and right ventricle. The AV node lies at the lower back section 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 is quite compact ( ~ 1 x 3 x 5 mm ). Contents 1 Structure 1.1 Location 1.2 Blood supply 1.3 Development 2 Function 3 Clinical significance 4 See also 5 References 6 External links Structure Location The AV node lies at the lower back section 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 is quite compact ( ~ 1 x 3 x 5 mm ). It is located at the center of Koch 's triangle -- a triangle enclosed by the septal leaflet of the tricuspid valve, the coronary sinus, and the membranous part of the interatrial septum. Blood supply The blood supply of the AV node is from the atrioventricular nodal branch. The origin of this artery is most commonly ( about 90 % of hearts ) a branch of the right coronary artery, with the remainder originating from the left circumflex artery. This is associated with the dominance of the coronary artery circulation. In right - dominant individuals the blood supply is from the right coronary artery while in left dominant individuals it originates from the left circumflex artery. Development BMP ( Bone morphogenetic protein ) cell signaling plays a key role in diverse aspects of cardiac differentiation and morphogenesis. ( BMPs ) are multifunctional signaling molecules critical for the development of AV node. BMP influences AV node development through Alk3 receptor ( Activin receptor - like kinase 3 ). Abnormalities seen in BMP and Alk3 are associated with some cardiovascular diseases like Ebstein 's anomaly and AV conduction disease. Function Isolated heart conduction system showing atrioventricular node The AV node receives two inputs from the right atrium : posteriorly, via the crista terminalis, and anteriorly, via the interatrial septum. Contraction of heart muscle cells requires depolarization and repolarization of their cell membranes. Movement of ions across cell membranes causes these events. The cardiac conduction system ( and AV node part of it ) coordinates myocyte mechanical activity. A wave of excitation spreads out from the sinoatrial node through the atria along specialized conduction channels. This activates the AV node. The atrioventricular node delays impulses by approximately 0.12 s. This delay in the cardiac pulse is extremely important : It ensures that the atria have ejected their blood into the ventricles first before the ventricles contract. This also protects the ventricles from excessively fast rate response to atrial arrhythmias ( see below ). AV conduction during normal cardiac rhythm occurs through two different pathways : the first `` pathway '' has a slow conduction velocity but shorter refractory period the second `` pathway '' has a faster conduction velocity but longer refractory period. 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 AV node 's normal intrinsic firing rate without stimulation ( such as that from the SA node ) is 40 - 60 times / minute. This property is important because loss of the conduction system before the AV node should still result in pacing of the ventricles by the -- slower -- pacemaking ability of the AV node. Clinical significance Atrioventricular conduction disease ( AV block ) describes impairment of the electrical continuity between the atria and ventricles. It occurs when the atrial depolarization fail to reach the ventricles or is conducted with an abnormally long delay. It can result from an injury or be a genetically inherited disorder. Atrioventricular nodal re-entry tachycardia. Cystic tumour of atrioventricular nodal region ( CTAVN ) CTAVN is of endodermal origin and occurs exclusively in the area of the AV node, tricuspid valve, and interatrial septum. See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. Junctional rhythm References ^ Jump up to : Gray, Huon H. ; Keith D. Dawkins ; Iain A. Simpson ; John M. Morgan ( 2002 ). Lecture Notes on Cardiology. Boston : Blackwell Science. p. 135. ISBN 978 - 0 - 86542 - 864 - 5. Jump up ^ Full Size Picture triangle of - Koch. jpg. Retrieved on 2008 - 12 - 22 Jump up ^ Full Size Picture triangle of - Koch. jpg. Retrieved on 2008 - 12 - 22 Jump up ^ Harrison 's Principles of Internal Medicine, 17e '' Section 3 : Disorders of Rhythm Archived July 7, 2011, at the Wayback Machine. Jump up ^ Van der Hauwaert LG, Stroobandt R, Verhaeghe L ( October 1972 ). `` Arterial blood supply of the atrioventricular node and main bundle ''. British Heart Journal. 34 ( 10 ) : 1045 -- 51. PMC 458545. PMID 5086972. doi : 10.1136 / hrt. 34.10. 1045. Jump up ^ Pejković, B. ; Krajnc, I. ; Anderhuber, F. ; Kosutić, D. ( 2008 ). `` Anatomical aspects of the arterial blood supply to the sinoatrial and atrioventricular nodes of the human heart ''. The Journal of international medical research. 36 ( 4 ) : 691 -- 698. PMID 18652764. doi : 10.1177 / 147323000803600410. Jump up ^ Saremi, F. ; Abolhoda, A. ; Ashikyan, O. ; Milliken, J.C. ; Narula, J. ; Gurudevan, S.V. ; Kaushal, K. ; Raney, A. ( 2007 ). `` Arterial Supply to Sinuatrial and Atrioventricular Nodes : Imaging with Multidetector CT ''. Radiology. 246 ( 1 ) : 99 -- 107 ; discussion 108 -- 9. PMID 18024438. doi : 10.1148 / radiol. 2461070030. Jump up ^ Stroud DM, Gaussin V, Burch JB, et al. ( November 2007 ). `` Abnormal Conduction and Morphology in the Atrioventricular Node of Mice With Atrioventricular Canal -- Targeted Deletion of Alk3 / Bmpr1a Receptor ''. Circulation. 116 ( 22 ) : 2535 -- 43. PMC 2947829. PMID 17998461. doi : 10.1161 / CIRCULATIONAHA. 107.696583. Jump up ^ Fuster V, Rydén LE, Asinger RW, et al. ( October 2001 ). `` ACC / AHA / ESC guidelines for the management of patients with atrial fibrillation '' ( PDF ). Journal of the American College of Cardiology. 38 ( 4 ) : 1231 -- 66. PMID 11583910. doi : 10.1016 / S0735 - 1097 ( 01 ) 01587 - X. Jump up ^ Campbell, N., & Reece, J. ( 2002 ). Biology. 6th ed. San Francisco : Benjamin Cummings Jump up ^ Gray, Huon H. ; Keith D. Dawkins ; Iain A. Simpson ; John M. Morgan ( 2002 ). Lecture Notes on Cardiology. Boston : Blackwell Science. p. 136. ISBN 978 - 0 - 86542 - 864 - 5. ^ Jump up to : Gray, Huon H. ; Keith D. Dawkins ; Iain A. Simpson ; John M. Morgan ( 2002 ). Lecture Notes on Cardiology. Boston : Blackwell Science. p. 157. ISBN 978 - 0 - 86542 - 864 - 5. Jump up ^ Patterson E, Scherlag BJ ( October 2002 ). `` Decremental conduction in the posterior and anterior AV nodal inputs ''. Journal of Interventional Cardiac Electrophysiology. 7 ( 2 ) : 137 -- 48. PMID 12397223. doi : 10.1023 / A : 1020833604423. Jump up ^ Guyton, Arthur C. ; John E. Hall ( 2006 ). Textbook of Medical Physiology ( 11 ed. ). Philadelphia : Elsevier Saunders. p. 120. ISBN 0 - 7216 - 0240 - 1. Jump up ^ Benson DW ( October 2004 ). `` Genetics of atrioventricular conduction disease in humans ''. The Anatomical Record Part A : Discoveries in Molecular, Cellular, and Evolutionary Biology. 280 ( 2 ) : 934 -- 9. PMID 15372490. doi : 10.1002 / ar. a. 20099. Jump up ^ Sharma G, Linden MD, Schultz DS, Inamdar KV ( January 2009 ). `` Cystic tumor of the atrioventricular node : an unexpected finding in an explanted heart ''. Cardiovascular Pathology. 19 ( 3 ) : e75 -- 8. PMID 19144541. doi : 10.1016 / j. carpath. 2008.10. 011. External links Anatomy figure : 20 : 06 - 02 at Human Anatomy Online, SUNY Downstate Medical Center - `` The conduction system of the heart. '' thoraxlesson4 at The Anatomy Lesson by Wesley Norman ( Georgetown University ) ( thoraxheartinternalner ) https://web.archive.org/web/20070929080346/http://www.healthyheart.nhs.uk/heart_works/heart03.shtml Anatomy of the heart General Surface base apex sulci coronary interatrial anterior interventricular posterior interventricular borders right left Internal atria interatrial septum pectinate muscles terminal sulcus ventricles interventricular septum trabeculae carneae chordae tendineae papillary muscle valves cusps atrioventricular septum cardiac skeleton intervenous tubercle Chambers Right heart ( venae cavae, coronary sinus ) → right atrium ( atrial appendage, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of inferior vena cava, valve of coronary sinus ) → tricuspid valve → right ventricle ( infundibulum, moderator band / septomarginal trabecula ) → pulmonary valve → ( pulmonary artery and pulmonary circulation ) Left heart ( pulmonary veins ) → left atrium ( atrial appendage ) → mitral valve → left ventricle → aortic valve ( aortic sinus ) → ( aorta and systemic circulation ) Layers Endocardium heart valves Myocardium Conduction system cardiac pacemaker SA node AV node bundle of His bundle branches Purkinje fibers Pericardial cavity pericardial sinus Pericardium fibrous pericardium sternopericardial ligaments serous pericardium epicardium / visceral layer fold of left vena cava Blood supply Circulatory system Coronary circulation Coronary arteries Retrieved from `` https://en.wikipedia.org/w/index.php?title=Atrioventricular_node&oldid=796175858 '' Categories : Cardiac anatomy Hidden categories : Webarchive template wayback links Wikipedia articles needing page number citations from September 2010 Medicine infobox template using Dorlands parameter Talk Contents About Wikipedia Bosanski Català Čeština Deutsch Español فارسی Français Galego हिन्दी Italiano മലയാളം Nederlands 日本 語 Plattdüütsch Polski Português کوردی Suomi Svenska తెలుగు 中文 Edit links This page was last edited on 19 August 2017, at 00 : 52. 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Question: which component of the cardiac conductions system acts as the main pacemaker
Answer: atrioventricular node, or AV node