chap13outline - Chapter 13 Cardiovascular System 13.1...

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13.1 Introduction (p. 344; Fig. 13.1) A. A functional cardiovascular system is vital for supplying oxygen and nutrients to tissues and removing wastes from them. 13.2 Structure of the Heart (p. 344; Fig. 13.2) A. The heart is a hollow, cone-shaped, muscular pump within the thoracic cavity. B. Size and Location of the Heart (p. 344) 1. The average adult heart is 14 cm long and 9 cm wide. 2. The heart lies in the mediastinum under the sternum; its apex extends to the fifth intercostal space. C. Coverings of the Heart (p. 344; Fig. 13.3) 1. The pericardium encloses the heart. 2. It is made of two layers: the outer, tough connective tissue fibrous pericardium surrounding a more delicate visceral pericardium (epicardium) that surrounds the heart. 3. At the base of the heart, the visceral pericardium folds back to become the parietal pericardium that lines the fibrous pericardium. 4. Between the parietal and visceral pericardia is a potential space (pericardial cavity) filled with serous fluid. D. Wall of the Heart (p. 345) 1. The wall of the heart is composed of three distinct layers. 2. The outermost layer, the epicardium, is made up of connective tissue and epithelium, and houses blood and lymph capillaries along with coronary arteries. 3. The middle myocardium consists of cardiac muscle and is the thickest layer of the heart wall. 4. The inner endocardium is smooth and is made up of connective tissue and epithelium, and is continuous with the endothelium of major vessels joining the heart. a. The endocardium houses Purkinje fibers. E. Heart Chambers and Valves (p. 346; Figs. 13.4-13.6; Table 13.1) 1. The heart has four internal chambers: two atria on top and two ventricles below. a. Atria receive blood returning to the heart and have thin walls and ear- like auricles projecting from their exterior. b. The thick-muscled ventricles pump blood to the body. 2. A septum divides the atrium and ventricle on each side and contains an atrioventricular orifice, each guarded by an atrioventricular (A-V) valve. a. The right A-V valve (tricuspid) and left A-V valve (bicuspid or mitral valve) have cusps to which chordae tendinae attach. b. Chordae tendinae are, in turn, attached to papillary muscles in the inner heart wall that contract during ventricular contraction to prevent the backflow of blood through the A-V valves. 3. The right ventricle has a thinner wall than does the left ventricle because it must pump blood only as far as the lungs, compared to the left ventricle pumping to the entire body. 4. At the base of the pulmonary trunk leading to the lungs is the pulmonary valve, which prevents a return flow of blood to the ventricle. 5.
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This note was uploaded on 05/20/2010 for the course PHYSIOLOGY Physiology taught by Professor Holes during the Spring '10 term at Open Uni..

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chap13outline - Chapter 13 Cardiovascular System 13.1...

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