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– Apex: Lower, pointed – Base: Upper,

flattened – Precordium: Anterior

chest overlying heart

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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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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,

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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)• Diagnostic tests

– Creatine phosphokinase (CPK)– Aspartate aminotransferase (AST)– Lactic dehydrogenase (LDH)– Troponin

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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. • Cardiac impulse spreads to AV node, left

atrium. 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.

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Electrocardiogram: Measurement of Electrical Activity

• P-wave: impulse depolarizing in atria

• QRS complex: impulse depolarizing in ventricles

• T-wave: impulse repolarizing in ventricles

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