Nursing Preparation Study Guide

Nursing Preparation Study Guide

3. The endocardium covers the inner surfaces of the heart, including the heart valves. This layer is composed of simple squamous epithelium that is continuous with the endothelium of the attached great vessels. Cardiac Muscle Tissue Cardiac muscle cells are interconnected by intercalated discs. At an intercalated disc, the interlocking membranes of adjacent cells are held together by desmosomes. Intercalated discs propagate action potentials and transfer the force of contraction quickly from cell to cell for an almost synchronized motion. Internal Anatomy and Organization The right atrium communicates with the right ventricle, and the left atrium with the left ventricle. A band of muscular tissue called a septum separates the right and left heart chambers. The thin interatrial septum separates the atria; the ventricles are separated by the much thicker interventricular septum. Atrioventricular (AV) valves , f olds of fibrous tissue, extend into the openings between the atria and ventricles. By definition, valves permit blood flow in only one direction. The valves between the upper and lower chambers allow flow from the atria to the ventricles and block flow that is moving in the opposite direction.

The Right Atrium The right atrium receives deoxygenated blood from the systemic circuit through the two great veins: the superior vena cava and the inferior vena cava . The superior vena cava delivers blood from the upper body. It opens into the superior region of the posterior right atrium and drains blood from the head, neck, upper limbs, and chest. The inferior vena cava opens

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