PATHOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -The sinus node sends electrical signals that typically start each heartbeat. These electrical signals move across the atria, causing the heart muscles to squeeze (contract) and pump blood into the ventricles.

Detailed explanation-3: -The distal portion of the AV node is known as the bundle of His. The bundle of His splits into two branches in the interventricular septum: the left bundle branch and the right bundle branch. The left bundle branch activates the left ventricle, while the right bundle branch activates the right ventricle.