
Its directed toward the right shoulder and its apex points inferiorly toward the left hip. The posterior surface has a broad, flat base about 9 cm (3.5 inches) wide. The left side of the heart pumps blood through the systemic circuit to all body tissues and back to the right side of the heart. The systemic and pulmonary circuits: The right side of the heart pumps blood through the pulmonary circuit. It rests on the superior surface of the diaphragm, lies posterior to the sternum and anterior to the vertebral column.

The heart is around the size of a fist and weighs between 250-350 grams (less than a pound).Įnclosed within the mediastinum, the medial cavity of the thorax, the heart extends obliquely from the second rib to the fifth intercostal space. The heart continually pumps oxygen, nutrients, waste and many other substances throughout the body.

The right ventricle and left ventricle pump blood through the two circuits. The right atrium and left atrium receive blood returning from the systemic and pulmonary circuits. The heart has two receiving chambers, and two pumping chambers. Blood vessels that carry blood to and from body tissues form the systemic circuit.

