Question

Cardiac muscle cells are __________.

		almost totally dependent on anaerobic metabolism
		mechanically, chemically, and electrically connected to one another
		multinucleated, with a low demand for nutrients
		nonstriated in appearance

Answer 1

Cardiac muscles are,

· mechanically, chemically, and electrically connected to one another The cardiac muscle cells are connected by the “intercalating discs,” which are absent in the skeletal muscles. The components of intercalating discs include the gap junctions and desmosomes. Gap junctions in the intercalated discs form the channels through which ions will be passed directly from the cytoplasm of the one cell to the other. So that the action potential can be transmitted from one cell to the other. Thus, these junctions will enable each cardiocyte to stimulate the neighbour cell electrically. Means, one cell of the cardiac tissue is stimulated means, the whole cardiac tissue will be activated as one unit, if the stimulus is sufficient. In this way, the cardiac muscles contract rhythmically and follow the “all-or-none” principle. This mass of cells that act as a single unit is known as “functional syncytium.” The two functional syncytia are present in the heart, one in the atrial walls (atrial syncystium) and the other in the ventricular walls (ventricular syncystium). The fibrous skeleton of the heart separate these masses, except at the atrial floor. At the right atrial floor, the atrial syncystium and ventricular syncystium are connected together by specialized conduction fibers.