NURS 201 Chapter Notes - Chapter 5: Tricuspid Valve, Mitral Valve, Pulmonary Artery
28 Apr 2013
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Document Summary
The heart is a four-chambered organ that lies in the mediastinal space in the thorax. The heart is divided by the septum, forming the right and left atrium and the right and left ventricle. The heart is: composed of three layers: endocardium, myocardium, and epicardium, surrounded by a fibroserous sac called the pericardium. The right side of the heart receives blood from the body (via the vena cava) and pumps it to the lungs where it is oxygenated. Blood returns to the left side of the heart (via the pulmonary arteries) and is pumped to the body via the aorta. The coronary circulation provides blood to the myocardium. The right and left coronary arteries are the first branches of the aorta. The conduction system consists of specialized cells that create and transport electrical impulses. These electrical impulses initiate depolarization (contraction) of the myocardium and ultimately a cardiac contraction.
