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Encyclopedia > SA node

The sinoatrial node (abbreviated SA node, also called the sinus node) is the impulse generating (pacemaker) tissue located in the right atrium of the heart.


It is richly innervated by vagal and sympathetic fibers. This makes the SA node susceptible to autonomic influences. Stimulation of the vagus nerve causes decrease in the SA node rate (thereby causing decrease in the heart rate). Stimulation via sympathetic fibers causes increase in the SA node rate (thereby increasing the heart rate).


Related topics


Cardiovascular system - Heart Edit (http://en.wikipedia.org/w/wiki.phtml?title=MediaWiki:Heart&action=edit)

Pericardium - Epicardium - Myocardium - Endocardium - Purkinje fibers - Cardiac pacemaker - Sinoatrial node - Atrioventricular node - Heart valves


  Results from FactBites:
 
Sinoatrial node - Wikipedia, the free encyclopedia (481 words)
The sinoatrial node (abbreviated SA node or SAN, also called the sinus node) is the impulse generating (pacemaker) tissue located in the right atrium of the heart.
The SA node is richly innervated by vagal and sympathetic fibers.
In the majority of patients, the SA node receives blood from the right coronary artery, meaning that a myocardial infarction occluding it will cause ischaemia in the SA node unless there is a sufficiently good anastomosis from the left coronary artery.
The Sinoatrial Node (278 words)
The depolarization and repolarization of the SA node and the other elements of the heart's electical system produces a strong pattern of voltage change which can be measured with electrodes on the skin.
The circuit involves a capacitor which is charged by the energy of a battery(roles played by the membranes of the SA node and the ion transport processes which repolarize it) and a resistor which controls the rate of flashing of the light.
In the case of the SA node, there is input frorm the physiology of the body related to oxygen demand and other factors which control the rate of firing of the SA node and therefore the heartrate.
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