Sinoatrial Node
Description
The Sinoatrial Node is a microscopic area of specialized cardiac muscle within the Heart located in the upper wall of the right atrium.
Biological Function of the Sinoatrial Node
Cardiovascular System
The Sinoatrial Node functions as the Heart's pacemaker:
It is composed of self-excitatory Cells that can generate impulses for Heart Muscle contractions at a rate of approximately 70 beats per minute.
From the Sinoatrial Node, impulses transfer to the Atrioventricular Node (AV Node) and on to the Heart Muscle.
Nervous System
The SA Node is under the influence of the Parasympathetic Nervous System - it receives Nerve Impulses via the Vagus Nerve:
Parasympathetic Nerve Impulses serve to slow down (or sometimes halt) Heartbeat.
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