Electrical Properties of the Heart

Abstract

The heart provides the main driving force for the movement of blood through the vessels. It is composed of two hollow organs—its right and its left half—with muscular walls (Fig. 5.1a). Each half comprises an atrium (Ra, La) and a ventricle (Rv, Lv). The right half receives oxygen-depleted blood from the body and expels it via the pulmonary artery (Pa) to the lungs, where it is reoxygenated. Then the blood returns to the left half of the heart and is thence distributed via the aorta (Ao) to the organs of the body (Fig. 5.1b). The movement of the blood from the right to the left heart, by way of the lungs, is called the pulmonary circulation. Its movement to and from the rest of the body is the systemic circulation. Strictly speaking, the two constitute a single pathway of blood movement, with the propulsive force provided at two points by the two halves of the heart (Fig. 5.1b).