Fundamentals of Anatomy & Physiology Eleventh Edition Chapter 20 The Heart Lecture Presentation by Lori Garrett, Parkland College © 2018 Pearson Education, Inc. Learning outcomes 20-1 Describe the anatomy oF the heart, including vascular supply and pericardium structure, and trace the Flow oF blood through the heart, identiFying the major blood vessels, chambers, and heart valves. 20-2 Explain the events oF an action potential in cardiac muscle, indicate the importance oF calcium ions to the contractile process, describe the conducting system oF the heart, and identiFy the electrical events associated with a normal electrocardiogram. 2 © 2018 Pearson Education, Inc. Learning outcomes 20-3 Explain the events oF the cardiac cycle, including atrial and ventricular systole and diastole, and relate the heart sounds to speciFic events in the cycle. 20-4 DeFine cardiac output, describe the Factors that inFluence heart rate and stroke volume, and explain how adjustments in stroke volume and cardiac output are coordinated at diFFerent levels oF physical activity. 3 © 2018 Pearson Education, Inc. An Introduction to the Heart § Cardiovascular system – Heart – Blood – Blood vessels § The heart – Beats approximately 100,000 times each day – Pumping about 8000 liters oF blood per day 4 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Pulmonary circuit – Carries blood to and From gas exchange surFaces oF lungs § Systemic circuit – Carries blood to and From the rest oF the body § Each circuit begins and ends at the heart – Blood travels through these circuits in sequence 5 © 2018 Pearson Education, Inc. Figure 20–1 An Overview of the Cardiovascular System. Systemic Circuit Capillaries in head and Pulmonary neck Circuit Pulmonary Systemic arteries arteries Capillaries Left in lungs atrium Pulmonary Left ventricle veins Capillaries in abdominal Right atrium organs Right ventricle Systemic veins Pulmonary Circuit Capillaries in upper limbs Pulmonary arteries Pulmonary veins Capillaries in trunk and lower limbs Systemic Circuit Systemic arteries Systemic veins 6 20-1 Anatomy of the Heart § Types oF blood vessels – Arteries • Carry blood away From heart – Veins • Return blood to heart – Capillaries (exchange vessels) • Interconnect smallest arteries and smallest veins • Exchange dissolved gases, nutrients, and wastes between blood and surrounding tissues 7 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Four chambers oF the heart – Right atrium • Receives blood From systemic circuit – Right ventricle • Pumps blood into pulmonary circuit – Left atrium • Receives blood From pulmonary circuit – LeFt ventricle • Pumps blood into systemic circuit 8 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Heart – Great vessels connect at base (superior) – Pointed tip is apex (inFerior) – Sits between two pleural cavities in mediastinum 9 © 2018 Pearson Education, Inc. Figure 20–2a The Location of the Heart in the Thoracic Cavity. Trachea Thyroid gland First rib (cut) Base of heart Right lung Left lung Apex of heart Diaphragm a An anterior view of the chest, showing the position of the heart and major blood vessels relative to the ribs, lungs, and diaphragm. 10 20-1 Anatomy of the Heart § Pericardium – Surrounds heart – Outer Fibrous pericardium – Inner serous pericardium • Outer parietal layer • Inner visceral layer (epicardium) – Pericardial cavity • Between parietal and visceral layers • Contains pericardial fluid 11 © 2018 Pearson Education, Inc. Figure 20–2b The Location of the Heart in the Thoracic Cavity. Posterior mediastinum Aorta (arch Esophagus segment removed) Left pulmonary artery Right pleural cavity Left pleural Right Left cavity lung lung Left pulmonary Bronchus of lung vein Right pulmonary Pulmonary trunk artery Aortic arch Right pulmonary Left atrium vein Left ventricle Superior vena cava Pericardial cavity Right atrium Visceral layer (epicardium) Right ventricle Pericardium Anterior mediastinum Sternum b A superior view of the organs in the mediastinum; portions of the lungs have been removed to reveal blood vessels and airways. The heart is located in the anterior part of the mediastinum, immediately posterior to the sternum. 12 Figure 20–2c The Location of the Heart in the Thoracic Cavity. Base of Cut edge of parietal layer Wrist (corresponds heart to base of heart) Fibrous pericardium Inner wall (visceral layer of serous pericardium) Parietal Layer of Serous Pericardium Air space (corresponds Areolar tissue to pericardial cavity) Mesothelium Outer wall (parietal layer Cut edge of visceral layer of of serous pericardium) serous pericardium (epicardium) Fibrous attachment to Apex of heart Balloon diaphragm c The relationship between the heart and the pericardial cavity; compare with the fist-and-balloon example. 13 20-1 Anatomy of the Heart § Pericarditis – Caused by pathogens in pericardium – InFlamed pericardial surFaces rub against each other • Producing distinctive scratching sound – May cause cardiac tamponade • Restricted movement oF the heart • Due to excess Fluid in pericardial cavity 14 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § SuperFicial anatomy oF the heart – Two thin-walled atria • Each with an expandable outer auricle – Sulci (grooves) • Contain Fat and blood vessels • Coronary sulcus – Marks border between atria and ventricles • Anterior interventricular sulcus and posterior interventricular sulcus – Mark boundary between leFt and right ventricles 15 © 2018 Pearson Education, Inc. Figure 20–3a The Position and Superficial Anatomy of the Heart. Base of heart 1 1 Ribs 2 2 3 3 4 4 5 5 6 6 7 7 Apex of heart 8 8 9 9 10 10 a Heart position relative to the rib cage. 16 Figure 20–3b The Position and Superficial Anatomy of the Heart. Left common Left subclavian artery carotid artery Brachiocephalic Ligamentum Arch of trunk arteriosum aorta Descending aorta Ascending aorta Left pulmonary artery Superior vena cava Pulmonary trunk Auricle Auricle of of right Right left atrium atrium atrium Right Fat and vessels ventricle in anterior interventricular sulcus Fat and vessels in Left coronary ventricle sulcus b Major anatomical features on the anterior surface. 17 Figure 20–3c The Position and Superficial Anatomy of the Heart. Left subclavian artery Left common carotid artery Ligamentum Brachiocephalic trunk arteriosum Left pulmonary Ascending artery aorta Pulmonary Superior trunk vena cava Auricle of left atrium Auricle of Left coronary artery right atrium (LCA) Right atrium Anterior interventricular Right Right sulcus coronary ventricle artery Left ventricle Coronary sulcus Anterior interventricular Marginal branch branch of LCA of right coronary artery c Anterior surface of the heart, cadaver dissection. 18 Figure 20–3d The Position and Superficial Anatomy of the Heart. Arch of aorta Left pulmonary artery Right pulmonary Left pulmonary veins artery Fat and vessels Superior in coronary Left vena cava sulcus atrium Coronary Right sinus pulmonary veins Right (superior Left atrium and inferior) ventricle Right Inferior ventricle vena cava Fat and vessels in posterior interventricular sulcus d Major anatomical features on the posterior surface. Coronary arteries (which supply the heart itself) are shown in red; coronary veins are shown in blue. 19 20-1 Anatomy of the Heart § Heart wall consists oF three distinct layers – Visceral layer of serous pericardium (epicardium) • Covers surFace oF heart • Covered by parietal layer of serous pericardium – Myocardium • Cardiac muscle tissue – Endocardium • Covers inner surFaces oF heart • Simple squamous epithelium and areolar tissue 20 © 2018 Pearson Education, Inc. Figure 20–4a The Heart Wall. Pericardial cavity Parietal Layer of Myocardium Serous Pericardium Cardiac Dense fibrous layer muscle cells Areolar tissue Connective tissues Mesothelium Artery Vein Endocardium Endothelium Visceral Layer of Serous Pericardium Areolar tissue Mesothelium Areolar tissue a A diagrammatic section through the heart wall, showing the relative positions of the myocardium, pericardium, and endocardium. The proportions are not to scale; the thickness of the myocardial wall has been greatly reduced. 21 Figure 20–4b The Heart Wall. Atrial musculature forms bands that wrap around the atria in a figure-eight pattern Ventricular musculature forms bands that spiral around the ventricles b Cardiac muscle tissue forms concentric layers that wrap around the atria or spiral within the walls of the ventricles. 22 20-1 Anatomy of the Heart § Connective tissues oF the heart – Physically support cardiac muscle Fibers, blood vessels, and nerves oF myocardium – Distribute Forces oF contraction – Add strength and prevent overexpansion oF heart – Provide elasticity that helps return heart to original size and shape aFter contraction 23 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Cardiac skeleton – Four dense bands oF tough elastic tissue • Encircle heart valves and bases oF pulmonary trunk and aorta • Stabilize positions oF heart valves and ventricular muscle cells • Electrically insulate ventricular cells From atrial cells 24 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Internal anatomy and organization – Chambers oF heart are separated by muscular partitions (septa) – Interatrial septum • Separates atria – Interventricular septum • Separates ventricles • Much thicker than interatrial septum 25 © 2018 Pearson Education, Inc. 20-1 Anatomy of the Heart § Atrioventricular (AV) valves – Tricuspid and mitral valves – Folds oF Fibrous tissue that extend into openings