Chapter 11 The Cardiovascular System

Essentials of Human Anatomy & Physiology INTERESTING FACTS ABOUT THE HEART ... Seventh Edition Elaine N. Marieb • http://www.webmd.com/heart/featu...
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Essentials of Human Anatomy & Physiology

INTERESTING FACTS ABOUT THE HEART ...

Seventh Edition

Elaine N. Marieb

• http://www.webmd.com/heart/features/amazingfacts-about-heart-health-and-heart-disease_

Chapter 11 The Cardiovascular System

Slides 11.1 – 11.19 Lecture Slides in PowerPoint by Jerry L. Cook Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Cardiovascular System

The Heart

• A closed system of the heart and blood vessels

• Location

• The heart pumps blood

• Thorax between the lungs

• Blood vessels allow blood to circulate to all parts of the body

• Pointed apex directed toward left hip

• The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.1

The Heart

• About the size of your fist

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.2a

The Heart: Coverings • Pericardium – a double serous membrane • Visceral pericardium • Next to heart • Parietal pericardium • Outside layer

• Serous fluid fills the space between the layers of pericardium Figure 11.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.2b

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Slide 11.3

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Heart Covering

The Heart: Heart Wall

• Pericardial physiology

• Three layers

• Protects and anchors heart

• Epicardium • Outside layer • This layer is the parietal pericardium • Connective tissue layer

• Prevents overfilling

• Myocardium • Middle layer • Mostly cardiac muscle

• Endocardium • Inner layer • Endothelium Figure 19.2

External Heart Anatomy

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Slide 11.4

The Heart: Chambers • Right and left side act as separate pumps • Four chambers • Atria • Receiving chambers • Right atrium • Left atrium

• Ventricles • Discharging chambers • Right ventricle • Left ventricle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 11.2a

Slide 11.5

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Slide 11.6

Atria of the Heart Ventricles of the Heart • Atria are the receiving chambers of the heart • Each atrium has a protruding auricle

• Ventricles are the discharging chambers of the heart

• Pectinate muscles mark atrial walls

• Papillary muscles and trabeculae carneae muscles mark ventricular walls

• Blood enters right atria from superior and inferior venae cavae and coronary sinus

• Right ventricle pumps blood into the pulmonary trunk

• Blood enters left atria from pulmonary veins

• Left ventricle pumps blood into the aorta

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Blood Circulation

Pathway of Blood through the Heart and Lungs

• Right atrium  tricuspid valve  right ventricle • Right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs • Lungs  pulmonary veins  left atrium • Left atrium  bicuspid valve  left ventricle • Left ventricle  aortic semilunar valve  aorta • Aorta  systemic circulation Figure 11.3 Slide 11.7

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Heart: Valves

Gross Anatomy of Heart: Frontal Section

• Allow blood to flow in only one direction • Four valves • Atrioventricular valves – between atria and ventricles • Bicuspid valve (left) • Tricuspid valve (right)

• Semilunar valves between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve Figure 19.4e Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.8

The Heart: Valves

Heart Valves

• Valves open as blood is pumped through • Held in place by chordae tendineae (“heart strings”) • Close to prevent backflow

Figure 19.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.9

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The Heart: Associated Great Vessels

Operation of Heart Valves

• Aorta • Leaves left ventricle

• Pulmonary arteries • Leave right ventricle

• Vena cava • Enters right atrium

• Pulmonary veins (four) • Enter left atrium

Figure 11.4 Slide 11.10

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Coronary Circulation

Slide 11.11

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The Heart: Conduction System

• Blood in the heart chambers does not nourish the myocardium • Intrinsic conduction system (nodal system)

• The heart has its own nourishing circulatory system

• Heart muscle cells contract, without nerve impulses, in a regular, continuous way

• Coronary arteries • Cardiac veins • Blood empties into the right atrium via the coronary sinus Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.12

The Heart: Conduction System

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Slide 11.13a

Heart Contractions

• Special tissue sets the pace

• Contraction is initiated by the sinoatrial node

• Sinoatrial node • Pacemaker

• Sequential stimulation occurs at other autorhythmic cells

• Atrioventricular node • Atrioventricular bundle • Bundle branches • Purkinje fibers Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.13b

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Slide 11.14a

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Heart Physiology: Sequence of Excitation

Heart Physiology: Sequence of Excitation

• AV bundle splits into two pathways in the interventricular septum (bundle branches)

• Sinoatrial (SA) node generates impulses about 75 times/minute • Atrioventricular (AV) node delays the impulse approximately 0.1 second

• Bundle branches carry the impulse toward the apex of the heart

• Impulse passes from atria to ventricles via the atrioventricular bundle (bundle of His)

• Purkinje fibers carry the impulse to the heart apex and ventricular walls

Heart Contractions • http://www.youtube.com/watch?v=te_SY3MeWy s

Figure 11.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.14b

Electrocardiography

Electrocardiography

• Electrical activity is recorded by electrocardiogram (ECG) • P wave corresponds to depolarization of atria • QRS complex corresponds to ventricular depolarization • T wave corresponds to ventricular repolarization • Atrial repolarization record is masked by the larger QRS complex

Figure 19.16

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Filling of Heart Chambers – the Cardiac Cycle • http://www.youtube.com/watch?v=jLTdgrhpDCg • http://www.youtube.com/watch?v=r32VObKw0g Y

Figure 11.6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.15

The Heart: Cardiac Cycle

The Heart: Cardiac Cycle • Cardiac cycle – events of one complete heart beat

• Atria contract simultaneously

• Mid-to-late diastole – blood flows into ventricles

• Atria relax, then ventricles contract • Systole = contraction

• Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood

• Diastole = relaxation

• Early diastole – atria finish re-filling, ventricular pressure is low Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.16

The Heart: Cardiac Output

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Slide 11.17

Cardiac Output Regulation

• Cardiac output (CO) • Amount of blood pumped by each side of the heart in one minute • CO = (heart rate [HR]) x (stroke volume [SV])

• Stroke volume • Volume of blood pumped by each ventricle in one contraction Figure 11.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.18

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 11.19

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