Definitions for "Sinus node"
(Also called "Sinoatrial [SA] Node.") The Sinus Node is a specialized group of cells in the heart which generates an electrical signal that travels down a single electrical road (the AV Node) connecting the atria to the ventricles. The Sinus Node is called the heart's "natural pacemaker," because it maintains a regular heart beat and makes adjustments to increase the heart rate during exercise and to slow it during rest. See Overview.
A small group of specialized heart muscle fibers located in the wall of the right atrium of the heart that act as a pacemaker by generating at regular intervals the electric impulses of the heartbeat. Reference: H1
The part of the heart which produces the electrical impulses that control the hearts pumping action.