THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -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. They receive blood from your body and empty it into the ventricles.

Detailed explanation-2: -Heart block is a delay in the electrical signals that progress from the heart’s upper chambers (atria) to its lower chambers (ventricles).

Detailed explanation-3: -The electrical signals, or impulses, of the heart are generated by a clump of specialized tissue called the sinus node. Each time the sinus node generates a new electrical impulse, that impulse spreads out through the heart’s upper chambers, called the right atrium and the left atrium.