GROSS ANATOMY

Detailed explanation-1: -The atrioventricular node delays the SA node’s electrical signal. It delays the signal by a consistent amount of time (a fraction of a second) each time. The delay ensures that your atria are empty of blood before the contraction stops. The atria are the heart’s upper chambers.

Detailed explanation-2: -The electrical impulse travels from the sinus node to the atrioventricular node (also called AV node). There, impulses are slowed down for a very short period, then continue down the conduction pathway via the bundle of His into the ventricles.

Detailed explanation-3: -The AV node functions as a critical delay in the conduction system. This delay prevents the atria & ventricles from contracting at the same time, which would cause an ineffective flow of blood through the heart.

Detailed explanation-4: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.