The Human Body in Health and Illness, 4th 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.
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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,
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Heart: Layers and Covering
• Three layers of heart– Endocardium– Myocardium– Epicardium
• Pericardium• Pericardial space,
with 10 to 30 mL fluid
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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.
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A Double Pump andTwo Circulations
• Double pump – Right heart (blue)– Left heart (red)
• Two circulations– Pulmonic– Systemic
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Chambers and Great Vessels
Chambers• Right atrium• Left atrium• Right ventricle• Left ventricle
Great Vessels• Venae cavae• Pulmonary artery• Pulmonary veins• Aorta
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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
• AortaCopyright © 2011, 2007 by Saunders,
an imprint of Elsevier Inc. All rights reserved.
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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
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Heart Valves: Semilunar Valves
• Pulmonic valve– Between right
ventricle and pulmonary artery
• Aortic valve – Between left
ventricle and aorta
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Auscultation of Heart Valves
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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.
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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
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•Left atrium• Bicuspid (mitral)
valve•Left ventricle
• Aortic valve• Aorta
Blood Supply to the Myocardium
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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.
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Diminished Coronary Blood Flow• Ischemia (diminished blood flow and oxygen
deprivation)
• Angina (chest pain)
• Myocardial infarction (heart attack)
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Cardiac Conduction System
SA node
AV node Left atrium
Bundle of His
Purkinje fibers
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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.
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