Biology Internal Transport in Animals?

Question

Describe the role of the SA node and the AV node in regulation of the heart beat.

What type of signal is released by these structures?

Answer 1

The sinoatrial node (SA node), located in the upper part of the wall of the right atrium, is the heart's natural pacemaker.  The SA node is a cluster of cells that generate electrical impulses that move cell to cell until they reach the atrioventricular node (AV node).

The AV node lies between the atria and the ventricles.  The AV node serves as a sort of gateway that slows the electrical current before it passes to the ventricles.  This allows the atria to fully contract before the venticles are stimulated.