Functional Morphology of the Cardiac Myocyte

Abstract Cardiac myocytes are the contractile cells that enable the heart to function as a pump. They are, thus, responsible for ensuring that sufficient oxygenated blood and metabolites reach the tissues to meet the body’s needs, whether at rest or during exercise. Each myocyte beats over three billion times in a typical human lifespan; to work as an effective pump, the activities of over three billion myocytes must be synchronized. To fulfill these functions, the cardiac myocyte is equipped with highly specialized subcellular machinery. With the aid of a range of complementary high resolution imaging techniques, this chapter illustrates and explains how the key structural components of the myocyte are organized to enable the coupling of electrical excitation to contraction of the myofibrils, and how the contractile activities of individual cells are coordinated to achieve organ function.