Ch20NotesFall11

Ch20NotesFall11 - Ch 20 The Heart The heart is the muscular pump of the cardiovascular system It performs ~ 100,000 heartbeats/day It pumps ~ 8000

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1 Fig. 20-3, p. 685 Ch. 20 – The Heart • The heart is the muscular pump of the cardiovascular system – It performs ~ 100,000 heartbeats/day • It pumps ~ 8000 liters of blood/day Fig. 20-1, p. 682 A review of the organization of the cardiovascular system • The heart is a double pump… – The right heart : • Powers the pulmonary circuit • Pumps blood to and from the lungs • Receives blood from the systemic circuit – The left heart : • Powers the systemic circuit • Pumps blood to and from the rest of the body • Receives blood from the pulmonary circuit
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2 Fig. 20-2a, p. 683 The location of the heart Fig. 20-2b, p. 671 The location of the heart
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3 Fig. 20-2, p. 683 The pericardium • Has 3 layers : –A . Visceral pericardium (epicardium) covers the outer surface of the heart –B . Parietal pericardium lines the inner surface of the pericardial sac •A cavity filled with lubricating fluid is found between the visceral and parietal layers –C . Pericardial sac (fibrous pericardium) surrounds and stabilizes the heart Fig. 20-4, p. 686 The heart wall Also has 3 layers (note the overlap with the 3 layers of the pericardium): . Epicardium (visceral pericardium) = mesothelium + areolar CT . Myocardium = cardiac muscle tissue; it’s the thickest layer . Endocardium = simple squamous epithelium + areolar CT • It’s continuous with the endothelial lining of blood vessels
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4 Fig. 20-5, p. 687 Cardiac muscle tissue Adjacent cells are connected by intercalated discs – Desmosomes hold the cells together – Gap junctions electrically connect the cells • If one atrial cell depolarizes, all of them do (same with the ventricular cells) Fig. 20-3, p. 685 The superficial anatomy of the heart This is a focus of lab
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5 Fig. 20-6, p. 688 The sectional (internal) anatomy of the heart This is also a focus of lab Know the flow! A schematic diagram of the heart
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6 The right atrium Oxygen-poor blood enters from the: Superior vena cava (SVC) Inferior vena cava (IVC) Coronary sinus (from the coronary circulation) Pectinate muscles = muscular ridges •T h e foramen ovale (in the fetus ) becomes the fossa ovalis – The foramen ovale allows flow from the R. to L. atrium (bypassing the lungs) – The valvular flap of the foramen ovale closes at birth, and becomes the fossa ovalis by about 3 months of age Fig. 20-6, p. 688 The right ventricle Fig. 20-6, p. 688 h e R. atrioventricular (AV) valve is a.k.a. the tricuspid valve (it has 3 flaps) Chordae tendineae attach to the AV valves and papillary muscles Papillary muscles = cones of cardiac muscle – The chordae tendineae and papillary muscles prevent eversion of the AV valves – they do not open or close them Trabeculae carnae = muscular ridges –T h e moderator band is a special trabecula that conducts electrical impulses to some of the papillary muscles of the R. ventricle The R. ventricle ejects blood through the pulmonary valve the pulmonary trunk R.
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This note was uploaded on 12/29/2011 for the course BIOLOGY 24011 taught by Professor Pan during the Fall '11 term at HCCS.

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Ch20NotesFall11 - Ch 20 The Heart The heart is the muscular pump of the cardiovascular system It performs ~ 100,000 heartbeats/day It pumps ~ 8000

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