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The Cardiovascular System

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The Cardiovascular System Heart’s Place in the Circulation Essentials of Anatomy & Physiology, 4th Edition Martini / Bartholomew Heart Pumps Blood into Two Circuits in Sequence The Cardiovascular 1. Pulmonary circuit • To and from the lungs 12 System: The Heart 2. Systemic circuit • To and from the rest of the body PowerPoint® Lecture Outlines prepared by Alan Magid, Duke University Slides 1 to 65 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Heart’s Place in the Circulation Heart’s Place in the Circulation Three Kinds of Blood Vessels Two Sets of Pumping Chambers in Heart 1. Arteries 1. Right atrium • Carry blood away from heart and carry it to • Receives systemic blood the capillaries 2. Right ventricle 2. Capillaries • Pumps blood to lungs (pulmonary) • Connect arteries and veins 3. Left atrium • Exchange area between blood and cells • Receives blood from lungs 3. Veins 4. Left ventricle • Receive blood from capillaries and carry it • Pumps blood to organ systems (systemic) back to the heart Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Heart’s Place in the Circulation The Anatomy of the Heart Overview of the Pericardial Cavity Cardiovascular • Surrounds the heart System • Lined by pericardium • Two layers 1. Visceral pericardium (epicardium) • Covers heart surface 2. Parietal pericardium • Lines pericardial sac that surrounds heart Figure 12-1 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 1 The Anatomy of the Heart The Anatomy of the Heart The Location of the Heart in the Thoracic Cavity Surface Features of the Heart 1. Auricle —Outer portion of atrium 2.Coronary sulcus —Deep groove that marks boundary of atria and ventricles • Anterior & Posterior interventricular sulcus • Mark boundary between left and right ventricles • Sulci contain major cardiac blood vessels • Filled with protective fat Figure 12-2 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Anatomy of the Heart The Anatomy of the Heart The Surface The Surface Anatomy Anatomy of the Heart of the Heart Figure 12-3(a) Figure 12-3(a) 1 of 2 2 of 2 The Anatomy of the Heart The Anatomy of the Heart The Surface The Heart Wall Anatomy 1. Epicardium (visceral pericardium) of the Heart • Outermost layer • Serous membrane 2. Myocardium • Middle layer • Thick muscle layer 3. Endocardium • Inner lining of pumping chambers Figure 12-3(b) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 2 The Anatomy of the Heart The Anatomy of the Heart The Heart Wall The Heart Wall and Cardiac Muscle Tissue and Cardiac Muscle Tissue Figure 12-4 Figure 12-4(a) The Anatomy of the Heart The Anatomy of the Heart The Heart Wall The Heart Wall and Cardiac Muscle Tissue and Cardiac Muscle Tissue Figure 12-4(b) Figure 12-4(c) The Anatomy of the Heart The Anatomy of the Heart The Heart Wall Cardiac Muscle Cells and Cardiac • Shorter than skeletal muscle fibers Muscle Tissue • Have single nucleus • Have striations (sarcomere organization) • Depend on aerobic metabolism • Connected by intercalated discs • Make sure all cardiac muscle cells work together so the heart beats as one unit Figure 12-4(d) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 3 The Anatomy of the Heart Anatomy of the Heart Internal Anatomy and Organization 1. Interatrial septum • Separates atria 2. Interventricular septum • Separates ventricles 3. Atrioventricular valves (AV valves) • Located between atrium and ventricle • Ensure one-way flow from atrium to ventricle Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Anatomy of the Heart The Anatomy of the Heart Blood Flow in the Heart Blood Flow in the Heart (cont’d) 1. Superior and inferior venae cavae 3. Right ventricle pumps blood through pulmonary semilunar valve to pulmonary • Large veins carry systemic blood to right arteries atrium • Flows to lungs through right, left pulmonary 2. Right atrium sends blood to right ventricle arteries where it picks up oxygen • Flows through right AV valve 4. Pulmonary veins carry blood to left atrium • Bounded by three cusps (tricuspid valve) 5. Left atrium sends blood to left ventricle • Enters through left AV valve (bicuspid or • Cusps anchored to heart walls by mitral) chordae tendinae 6. Left ventricle pumps blood to aorta • Through aortic semilunar valve to systems Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Anatomy of the Heart The Anatomy of the Heart The Sectional Anatomy of the Heart Functional Anatomy of the Heart 1. Left ventricular myocardium much thicker than right • Why? 2. Valves ensure one-way flow of blood • Prevent backward flow (regurgitation) Figure 12-5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 4 The Anatomy of the Heart The Anatomy of the Heart The Valves of the Heart The Valves of the Heart Figure 12-6(a) PLAY The Heart: Anatomy Figure 12-6(b) The Anatomy of the Heart The Anatomy of the Heart Key Note The Blood Supply TO the Heart The heart has four chambers, the right • The myocardium needs lots of oxygen and atrium and ventricle with the pulmonary nutrients circuit and left atrium and ventricle with the • Coronary arteries (right, left) branch from systemic circuit. The left ventricle’s greater aorta base and supply blood to the heart workload makes it more massive than the muscle itself right, but the two pump equal amounts of • If a coronary artery becomes blocked, a blood. AV valves prevent backflow from the myocardial infarction (heart attack) occurs ventricles into the atria, and semilunar • Blockage usually occurs because of build valves prevent backflow from the outflow up of fat in coronary arteries vessels into the ventricles. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of the Heart The Anatomy of the Heart The Coronary Circulation A blocked coronary artery can be repaired by having coronary bypass surgery Figure 12-7(a) 5 The Anatomy of the Heart The Heartbeat The Coronary Circulation Heartbeat Needs two Types of Cardiac Cells 1. Contractile cells • Provide the pumping action 2. Cells of the conducting system • Generate and spread the action potential (electrical impulse) Figure 12-7(b) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Heartbeat 1 Rapid Depolarization 2 The Plateau 3 Repolarization Differences between Cardiac and Cause: Na+ entry Cause: Ca2+ entry Cause: K+ loss Duration: 3-5 msec Duration: ~175 msec Duration: 75 msec Ends with: Closure of Ends with: Closure of Ends with: Closure of Skeletal Muscle Cells voltage-regulated calcium channels potassium channels • Cardiac action potential has long sodium channels plateau phase +30 • Cardiac muscle has long, slow twitch 2 0 • Cardiac muscle has long refractory mV 1 period Stimulus 3 • Can’t be tetanized Refractory period –90 0 100 200 300 Time (msec) Figure 12-8(a) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 1 of 5 1 Rapid 1 Rapid Depolarization Depolarization 2 The Plateau Cause: Na+ entry Cause: Na+ entry Cause: Ca2+ entry Duration: 3-5 msec Duration: 3-5 msec Duration: ~175 msec Ends with: Closure of Ends with: Closure of Ends with: Closure of voltage-regulated voltage-regulated calcium channels sodium channels sodium channels +30 +30 2 0 0 mV 1 mV 1 Stimulus Stimulus –90 –90 0 100 200 300 0 100 200 300 Time (msec) Time (msec) Figure 12-8(a) Figure 12-8(a) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 2 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 3 of 5 6 1 Rapid 1 Rapid Depolarization 2 The Plateau 3 Repolarization Depolarization 2 The Plateau 3 Repolarization Cause: Na+ entry Cause: Ca2+ entry Cause: K+ loss Cause: Na+ entry Cause: Ca2+ entry Cause: K+ loss Duration: 3-5 msec Duration: ~175 msec Duration: 75 msec Duration: 3-5 msec Duration: ~175 msec Duration: 75 msec Ends with: Closure of Ends with: Closure of Ends with: Closure of Ends with: Closure of Ends with: Closure of Ends with: Closure of voltage-regulated calcium channels potassium channels voltage-regulated calcium channels potassium channels sodium channels sodium channels +30 +30 2 2 0 0 mV 1 mV 1 Stimulus 3 Stimulus 3 Refractory period –90 –90 0 100 200 300 0 100 200 300 Time (msec) Time (msec) Figure 12-8(a) Figure 12-8(a) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 4 of 5 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 5 of 5 The Heartbeat The Heartbeat Action Potentials and The Conducting System Muscle Cell • Initiates and spreads electrical impulses Contraction in Skeletal in heart and Cardiac Muscle • Two types of cells 1. Pacemaker cells (aka “nodes”) Reach threshold first Set heart rate 2. Conducting cells • Distributes stimuli to myocardium Figure 12-8(b) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings The Heartbeat The Heartbeat The Conducting System (cont’d) The Conducting • Steps in the Conduction System: System of the 1.Starts in ATRIA. Pacemaker cells Heart establish heart rate • pacemaker is also called sinoatrial (SA) node 2. Impulse spreads from SA node across atria 3. To atrioventricular (AV) node 4. To AV bundle and bundle branches PLAY The Heart: • Via Purkinje fibers to VENTRICLES Conduction System Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 12-9(a) 7 SA node activity and atrial SA node SA node activity and atrial SA node activation begin. activation begin. Time = 0 Time = 0 Stimulus spreads across the atrial surfaces and reaches the AV node.
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