The Human Body in Health and Illness, 4 th edition Barbara Herlihy Chapter 16: Anatomy of the Heart

Lesson 16-1 Objectives Describe the location of the heart. Name the three layers and covering of the heart. Explain the function of the heart as two separate pumps. Identify the four chambers of the heart. Explain the functions of the four heart valves. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

Heart: Size and Location Located between second rib and fifth intercostal space (What is your intercostal space?) – Apex: Lower, pointed – Base: Upper, flattened – Precordium: Anterior chest overlying heart Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3

Heart: Layers and Covering Three layers of heart – Endocardium – Myocardium – Epicardium Pericardium Pericardial space, with 10 to 30 mL fluid Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4

Layers of the heart Endocardium – the smooth, inner lining of the heart and great vessels Myocardium – cardiac muscle which allows the heart to act as a pump Epicardium – The outermost layer which becomes part of the pericardium. – Pericardium the sling supporting the heart, also has three layers. The outmost layer of the epicardium is also known as the visceral pericardium. At the base of the heart, it folds back, becomes the parietal pericardium, and forms the pericardial space. The outermost layer of the pericardium, the fibrous pericardium, anchors the heart to surrounding structures. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5

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A Double Pump and Two Circulations Double pump – Right heart (blue) – Left heart (red) Two circulations – Pulmonic – Systemic Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10

Chambers and Great Vessels Chambers Right atrium Left atrium Right ventricle Left ventricle Great Vessels Venae cavae Pulmonary artery Pulmonary veins Aorta Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11

Blood Flow Through the Heart Right atrium – From venae cavae Right ventricle – Pulmonary artery – Right and left lungs – Four pulmonary veins Left atrium Left ventricle Aorta Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12

Heart Valves: Atrioventricular (AV) Tricuspid between right atrium and ventricle Bicuspid (mitral) between left atrium and ventricle Cusps attached to ventricular walls by chordae tendineae Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13

Heart Valves: Semilunar Valves Pulmonic valve – Between right ventricle and pulmonary artery Aortic valve – Between left ventricle and aorta Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14

Auscultation of Heart Valves Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 15

Lesson 16-2 Objectives Describe the blood flow through the heart. List the vessels that supply blood to the heart. Identify the major components of the heart’s conduction system. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 16

Blood Flow Through the Heart Right atrium From venae cavae Tricuspid valve Right ventricle Pulmonic valve Pulmonary artery Right and left pulmonary capillaries Four pulmonary veins Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 17 Left atrium Bicuspid (mitral) valve Left ventricle Aortic valve Aorta

Blood Supply to the Myocardium Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 18

Characteristics of Coronary Blood Flow Flow can increase up to four to five times during exertion. Flow is greatest during myocardial relaxation. Coronary arteries can form anastomoses. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 19

Diminished Coronary Blood Flow Ischemia (diminished blood flow and oxygen deprivation) Angina (chest pain) Myocardial infarction (heart attack) Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 20

Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 21

Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 22

Cardiac Conduction System SA node AV node Left atrium Bundle of His Purkinje fibers Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 23

Cardiac Conduction System (cont’d.) SA node originates cardiac impulse. The SA node sets the rate at which the heart beats and is located in the upper posterior wall of the right atrium, it is the heart’s pacemaker. Cardiac impulse spreads to AV node, left atrium and the atria contract. AV node slows cardiac impulse and sends it to Bundle of His. Bundle of His sends cardiac impulse to Purkinje fibers throughout the ventricles. Ventricles contract. The Purkinje Fibers are simply fibers found throughout the ventricles. 24