PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 18 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart PART 1

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart  A muscular double pump  Pulmonary circuit – takes blood to and from the lungs  Systemic circuit – vessels transport blood to and from body tissues  Atria – receive blood from the pulmonary and systemic circuits  Ventricles – the pumping chambers of the heart

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Pulmonary and Systemic Circuits Figure 18.1

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax  Heart – typically weighs 250–350 grams (healthy heart)  Largest organ of the mediastinum  Located between the lungs  Apex lies to the left of the midline  Base is the broad posterior surface

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax Figure 18.2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Four “Corners” of the Heart  Superior right  At costal cartilage of third rib and sternum  Inferior right  At costal cartilage of sixth rib lateral to the sternum  Superior left  At costal cartilage of second rib lateral to the sternum  Inferior left  Lies in the fifth intercostal space at the midclavicular line

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax Figure 18.2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Coverings  Pericardium – two primary layers  Fibrous pericardium  Strong layer of dense connective tissue  Serous pericardium  Formed from two layers  Parietal pericardium  Visceral pericardium

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Coverings Figure 18.3

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Layers of the Heart Wall  Epicardium  Visceral layer of the serous pericardium  Myocardium  Consists of cardiac muscle  Muscle arranged in circular and spiral patterns  Endocardium  Endothelium resting on a layer of connective tissue  Lines the internal walls of the heart

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Layers of the Heart Wall Figure 18.4

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings PLAY Rotatable Heart Heart Chambers  Right and left atria  Superior chambers  Right and left ventricles  Inferior chambers  Internal divisions  Interventricular septa  Interatrial septa  External markings  Coronary sulcus  Anterior interventricular sulcus  posterior interventricular sulcus

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Chambers Figure 18.5b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Right Atrium  Forms right border of heart  Receives blood from systemic circuit  Pectinate muscles  Ridges inside anterior of right atrium  Crista terminalis  Landmark used to locate veins entering right atrium  Fossa ovalis  Depression in interatrial septum  Remnant of foramen ovale

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Right Ventricle  Receives blood from right atrium through the tricuspid valve  Pumps blood into pulmonary circuit via  Pulmonary trunk  Internal walls of right ventricle  Trabeculae carneae  Papillary muscles  Chordae tendineae

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Left Atrium  Makes up heart’s posterior surface  Receives oxygen-rich blood from lungs  Opens into the left ventricle through  Mitral valve (left atrioventricular valve)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Left Ventricle  Forms apex of the heart  Internal walls of left ventricle  Trabeculae carneae  Papillary muscles  Chordae tendineae  Pumps blood through systemic circuit via  Aortic semilunar valve (aortic valve) PLAY Rotatable Heart Section

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Chambers Figure 18.5e

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Inferior View of the Heart Figure 18.5d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Pathway of Blood Through the Heart  Beginning with oxygen-poor blood in the superior and inferior venae cavae  Go through pulmonary and systemic circuits  A blood drop passes through all structures sequentially  Atria contract together  Ventricles contract together

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Blood Flow Through the Heart Figure 18.6

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Pathway of Blood Through the Heart Figure 18.6b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heartbeat  70 – 80 beats per minute at rest  Systole – contraction of a heart chamber  Diastole – expansion of a heart chamber  Systole and diastole also refer to  Stage of heartbeat when ventricles contract and expand

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of Heart Wall  Walls differ in thickness  Atria – thin walls  Ventricles – thick walls  Systemic circuit  Longer than pulmonary circuit  Offers greater resistance to blood flow

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of Heart Wall  Left ventricle – three times thicker than right  Exerts more pumping force  Flattens right ventricle into a crescent shape Figure 18.7

PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 18 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart PART 2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart  A muscular double pump  Pulmonary circuit – takes blood to and from the lungs  Systemic circuit – vessels transport blood to and from body tissues  Atria – receive blood from the pulmonary and systemic circuits  Ventricles – the pumping chambers of the heart

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Pulmonary and Systemic Circuits Figure 18.1

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax  Heart – typically weighs 250–350 grams (healthy heart)  Largest organ of the mediastinum  Located between the lungs  Apex lies to the left of the midline  Base is the broad posterior surface

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax Figure 18.2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Four “Corners” of the Heart  Superior right  At costal cartilage of third rib and sternum  Inferior right  At costal cartilage of sixth rib lateral to the sternum  Superior left  At costal cartilage of second rib lateral to the sternum  Inferior left  Lies in the fifth intercostal space at the midclavicular line

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Location and Orientation within the Thorax Figure 18.2

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Coverings  Pericardium – two primary layers  Fibrous pericardium  Strong layer of dense connective tissue  Serous pericardium  Formed from two layers  Parietal pericardium  Visceral pericardium

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Coverings Figure 18.3

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Layers of the Heart Wall  Epicardium  Visceral layer of the serous pericardium  Myocardium  Consists of cardiac muscle  Muscle arranged in circular and spiral patterns  Endocardium  Endothelium resting on a layer of connective tissue  Lines the internal walls of the heart

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Heart – Layers of the Heart Wall Figure 18.4

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings PLAY Rotatable Heart Heart Chambers  Right and left atria  Superior chambers  Right and left ventricles  Inferior chambers  Internal divisions  Interventricular septa  Interatrial septa  External markings  Coronary sulcus  Anterior interventricular sulcus  posterior interventricular sulcus

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Chambers Figure 18.5b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Right Atrium  Forms right border of heart  Receives blood from systemic circuit  Pectinate muscles  Ridges inside anterior of right atrium  Crista terminalis  Landmark used to locate veins entering right atrium  Fossa ovalis  Depression in interatrial septum  Remnant of foramen ovale

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Right Ventricle  Receives blood from right atrium through the tricuspid valve  Pumps blood into pulmonary circuit via  Pulmonary trunk  Internal walls of right ventricle  Trabeculae carneae  Papillary muscles  Chordae tendineae

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Left Atrium  Makes up heart’s posterior surface  Receives oxygen-rich blood from lungs  Opens into the left ventricle through  Mitral valve (left atrioventricular valve)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Left Ventricle  Forms apex of the heart  Internal walls of left ventricle  Trabeculae carneae  Papillary muscles  Chordae tendineae  Pumps blood through systemic circuit via  Aortic semilunar valve (aortic valve) PLAY Rotatable Heart Section

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Chambers Figure 18.5e

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Inferior View of the Heart Figure 18.5d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Pathway of Blood Through the Heart  Beginning with oxygen-poor blood in the superior and inferior venae cavae  Go through pulmonary and systemic circuits  A blood drop passes through all structures sequentially  Atria contract together  Ventricles contract together

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Blood Flow Through the Heart Figure 18.6

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Pathway of Blood Through the Heart Figure 18.6b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heartbeat  70 – 80 beats per minute at rest  Systole – contraction of a heart chamber  Diastole – expansion of a heart chamber  Systole and diastole also refer to  Stage of heartbeat when ventricles contract and expand

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of Heart Wall  Walls differ in thickness  Atria – thin walls  Ventricles – thick walls  Systemic circuit  Longer than pulmonary circuit  Offers greater resistance to blood flow

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structure of Heart Wall  Left ventricle – three times thicker than right  Exerts more pumping force  Flattens right ventricle into a crescent shape Figure 18.7

PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 18 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart PART 3

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Valves – Valve Structure  Each valve composed of  Endocardium with connective tissue core  Atrioventricular (AV) valves  Between atria and ventricles  Aortic and pulmonary valves  At junction of ventricles and great arteries

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Skeleton  Surrounds all four valves  Composed of dense connective tissue  Functions  Anchors valve cusps  Prevents overdilation of valve openings  Main point of insertion for cardiac muscle  Blocks direct spread of electrical impulses

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Valves – Valve Structure Figure 18.8a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Function of the Atrioventricular Valves Figure 18.9a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Function of the Atrioventricular Valves Figure 18.9b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Function of the Semilunar Valves Figure 18.10a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Sounds  “Lub-dup” – sound of valves closing  First sound “lub”  The AV valves closing  Second sound “dup”  The semilunar valves closing

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Sounds Figure 18.8a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Sounds  Each valve sound – best heard near a different heart corner  Pulmonary valve – superior left corner  Aortic valve – superior right corner  Mitral (bicuspid) valve– at the apex  Tricuspid valve – inferior right corner

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Heart Sounds Figure 18.11

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Forms a thick layer called myocardium  Striated like skeletal muscle  Contractions pump blood through the heart and into blood vessels  Contracts by sliding filament mechanism

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Cardiac muscle cells  Short  Branching  Have one or two nuclei  Not fused colonies like skeletal muscle

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Cells join at intercalated discs  Complex junctions  Form cellular networks  Cells are separated by delicate endomysium  Binds adjacent cardiac fibers  Contains blood vessels and nerves

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Intercalated discs – complex junctions  Adjacent sarcolemmas interlock  Possess three types of cell junctions  Desmosomes  Fasciae adherans – long desmosome-like junctions  Gap junctions

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Cardiac Muscle Figure 18.12a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue Figure 18.12c, d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Triggered to contract by Ca 2+ entering the sarcoplasm  Signals sarcoplasmic reticulum to release Ca 2+ ions  Ions diffuse into sarcomeres  Trigger sliding filament mechanism

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Muscle Tissue  Not all cardiac cells are innervated  Will contract in rhythmic manner without innervation  Inherent rhythmicity  Is the basis for rhythmic heartbeat

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Conducting System  Cardiac muscle tissue has intrinsic ability to  Generate and conduct impulses  Signal these cells to contract rhythmically  Conducting system  A series of specialized cardiac muscle cells  Sinoatrial (SA) node sets the inherent rate of contraction

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Conducting System Figure 18.14

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Innervation  Heart rate is altered by external controls  Nerves to the heart include  Visceral sensory fibers  Parasympathetic branches of the vagus nerve  Sympathetic fibers – from cervical and upper thoracic chain ganglia Figure 18.15

PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 18 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Heart PART 4

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Blood Supply to the Heart  Functional blood supply  Coronary arteries  Arise from the aorta  Located in the coronary sulcus  Main branches  Left and right coronary arteries

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Blood Supply to the Heart Figure 18.16

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Disorders of the Heart  Coronary artery disease  Atherosclerosis – fatty deposits  Angina pectoris – chest pain  Myocardial infarction – blocked coronary artery  Heart attack  Silent ischemia – no pain or warning

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Disorders of the Heart  Heart failure  Progressive weakening of the heart  Cannot meet the body’s demands for oxygenated blood  Congestive heart failure (CHF)  Heart enlarges  Pumping efficiency declines  Cor pulmonale  Enlargement and potential failure of right ventricle