Copyright © 2010 Pearson Education, Inc. Heart Anatomy Approximately the size of a fist Location In the mediastinum between second rib and fifth intercostal space Directly on top of the diaphragm Two-thirds to the left of the midsternal line In front of the vertebral column, behind the sternum
Copyright © 2010 Pearson Education, Inc. Figure 18.1a Point of maximal intensity (PMI) Diaphragm (a) Sternum 2nd rib Midsternal line Enclosed in pericardium, a double-walled sac
Copyright © 2010 Pearson Education, Inc. Pericardium Outer layer is a tough, dense fibrous layer Protects, anchors, and prevents overfilling
Copyright © 2010 Pearson Education, Inc. Pericardium Double-walled sac that encloses the heart Inner Layer: Parietal layer lines the internal surface of the fibrous pericardium Visceral layer (epicardium) on external surface of the heart Separated by fluid-filled pericardial cavity (decreases friction)
Copyright © 2010 Pearson Education, Inc. The pericardium…. …you’ve got it in the bag!
Copyright © 2010 Pearson Education, Inc. Pericarditis – Inflammation of the pericardium Roughens the serous membrane surfaces Causes the beating heart to rub against pericardial sac Creates a pericardial friction rub heard with a stethoscope Can cause sever pain and inflammatory build up of fluid putting pressure on the heart causing a condition known as cardiac tamponade Treated by inserting a needle into the pericardial cavity and draining off excess fluid
Copyright © 2010 Pearson Education, Inc. Pericarditits
Copyright © 2010 Pearson Education, Inc. Layers of the Heart Wall 1.Epicardium— Outer, visceral layer of the serous pericardium 2.Myocardium – Middle muscular layer Forms the bulk of the heart 3.Endocardium - Lines the chambers of the heart
Copyright © 2010 Pearson Education, Inc. Figure 18.2 Fibrous pericardium Parietal layer of serous pericardium Pericardial cavity Epicardium (visceral layer of serous pericardium) Myocardium Endocardium Pulmonary trunk Heart chamber Heart wall Pericardium Myocardium
Copyright © 2010 Pearson Education, Inc. Figure 18.3 Cardiac muscle bundles
Copyright © 2010 Pearson Education, Inc. 4 Chambers of the Heart 2 Atria superiorily 2 Ventricles inferiorily
Copyright © 2010 Pearson Education, Inc. Chambers The Atria Separated internally by the interatrial septum Coronary sulcus (atrioventricular groove) encircles the junction of the atria and ventricles Auricles increase atrial volume
Copyright © 2010 Pearson Education, Inc. Chambers The ventricles Separated by the interventricular septum Anterior and posterior interventricular sulci mark the position of the septum externally
Copyright © 2010 Pearson Education, Inc. Figure 18.4b (b) Anterior view Brachiocephalic trunk Superior vena cava Right pulmonary artery Ascending aorta Pulmonary trunk Right pulmonary veins Right atrium Right coronary artery (in coronary sulcus) Anterior cardiac vein Right ventricle Right marginal artery Small cardiac vein Inferior vena cava Left common carotid artery Left subclavian artery Ligamentum arteriosum Left pulmonary artery Left pulmonary veins Circumflex artery Left coronary artery (in coronary sulcus) Left ventricle Great cardiac vein Anterior interventricular artery (in anterior interventricular sulcus) Apex Aortic arch Auricle of left atrium
Copyright © 2010 Pearson Education, Inc. Atria: The Receiving Chambers Walls are ridged by pectinate muscles Vessels entering right atrium Superior vena cava Inferior vena cava Coronary sinus Vessels entering left atrium Right and left pulmonary veins
Copyright © 2010 Pearson Education, Inc. Ventricles: The Discharging Chambers Walls are ridged by trabeculae carneae Papillary muscles project into the ventricular cavities Vessel leaving the right ventricle Pulmonary trunk Vessel leaving the left ventricle Aorta
Copyright © 2010 Pearson Education, Inc. Figure 18.4e Aorta Left pulmonary artery Left atrium Left pulmonary veins Mitral (bicuspid) valve Aortic valve Pulmonary valve Left ventricle Papillary muscle Interventricular septum Epicardium Myocardium Endocardium (e) Frontal section Superior vena cava Right pulmonary artery Pulmonary trunk Right atrium Right pulmonary veins Fossa ovalis Pectinate muscles Tricuspid valve Right ventricle Chordae tendineae Trabeculae carneae Inferior vena cava
Copyright © 2010 Pearson Education, Inc. Heart Valves Ensure unidirectional blood flow through the heart Atrioventricular (AV) valves Prevent backflow into the atria when ventricles contract Tricuspid valve (right) Mitral valve (left) Chordae tendineae anchor AV valve cusps to papillary muscles
Copyright © 2010 Pearson Education, Inc.
Heart Valves Semilunar (SL) valves Prevent backflow into the ventricles when ventricles relax Aortic semilunar valve Pulmonary semilunar valve
Copyright © 2010 Pearson Education, Inc. Figure 18.8a Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Myocardium Tricuspid (right atrioventricular) valve Mitral (left atrioventricular) valve Aortic valve Pulmonary valve (b) Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Myocardium Tricuspid (right atrioventricular) valve (a) Mitral (left atrioventricular) valve Aortic valve Pulmonary valve Fibrous skeleton Anterior
Copyright © 2010 Pearson Education, Inc. Figure 18.8b Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Myocardium Tricuspid (right atrioventricular) valve Mitral (left atrioventricular) valve Aortic valve Pulmonary valve (b)
Copyright © 2010 Pearson Education, Inc. Figure 18.8c Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Chordae tendineae attached to tricuspid valve flap Papillary muscle (c)
Copyright © 2010 Pearson Education, Inc. Figure 18.8d Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Mitral valve Chordae tendineae Interventricular septum Myocardium of left ventricle Opening of inferior vena cava Tricuspid valve Papillary muscles Myocardium of right ventricle (d)
Copyright © 2010 Pearson Education, Inc. Figure Blood returning to the heart fills atria, putting pressure against atrioventricular valves; atrioventricular valves are forced open. 1 Ventricles contract, forcing blood against atrioventricular valve cusps. 2 As ventricles fill, atrioventricular valve flaps hang limply into ventricles. 2 Atrioventricular valves close. 3 Atria contract, forcing additional blood into ventricles. 3 Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria. (a) AV valves open; atrial pressure greater than ventricular pressure (b) AV valves closed; atrial pressure less than ventricular pressure Direction of blood flow Atrium Ventricle Cusp of atrioventricular valve (open) Chordae tendineae Papillary muscle Atrium Blood in ventricle Cusps of atrioventricular valve (closed)
Copyright © 2010 Pearson Education, Inc. Figure As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open. As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close. (a) Semilunar valves open (b) Semilunar valves closed Aorta Pulmonary trunk
Copyright © 2010 Pearson Education, Inc. Pathway of Blood Through the Heart The heart is actually two side-by-side pumps Right side is the pump for the pulmonary circuit Vessels that carry blood to and from the lungs Left side is the pump for the systemic circuit Vessels that carry the blood to and from all body tissues
Copyright © 2010 Pearson Education, Inc. Figure 18.5 Oxygen-rich, CO 2 -poor blood Oxygen-poor, CO 2 -rich blood Capillary beds of lungs where gas exchange occurs Capillary beds of all body tissues where gas exchange occurs Pulmonary veins Pulmonary arteries Pulmonary Circuit Systemic Circuit Aorta and branches Left atrium Heart Left ventricle Right atrium Right ventricle Venae cavae
Copyright © 2010 Pearson Education, Inc. Pathway of Blood Through the Heart Right atrium tricuspid valve right ventricle Right ventricle pulmonary semilunar valve pulmonary trunk pulmonary arteries lungs
Copyright © 2010 Pearson Education, Inc. Pathway of Blood Through the Heart Lungs pulmonary veins left atrium Left atrium bicuspid valve left ventricle Left ventricle aortic semilunar valve aorta Aorta systemic circulation
Copyright © 2010 Pearson Education, Inc. Hmmm…. Notice Something Funny? W hat do arteries usually carry? What do veins usually carry? What’s going on in the heart?
Copyright © 2010 Pearson Education, Inc. Pathway of Blood Through the Heart Equal volumes of blood are pumped to the pulmonary and systemic circuits Pulmonary circuit is a short, low-pressure circulation Systemic circuit blood encounters much resistance in the long pathways Anatomy of the ventricles reflects these differences
Copyright © 2010 Pearson Education, Inc. Figure 18.6 Right ventricle Left ventricle Interventricular septum
Copyright © 2010 Pearson Education, Inc. Coronary Circulation The functional blood supply to the heart muscle itself Arterial supply varies considerably and contains many anastomoses (junctions) among branches Collateral routes provide additional routes for blood delivery
Copyright © 2010 Pearson Education, Inc. Coronary Circulation Arteries Right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries Veins Small cardiac, anterior cardiac, and great cardiac veins
Copyright © 2010 Pearson Education, Inc. Figure 18.7a Right ventricle Right coronary artery Right atrium Right marginal artery Posterior interventricular artery Anterior interventricular artery Circumflex artery Left coronary artery Aorta Anastomosis (junction of vessels) Left ventricle Superior vena cava (a) The major coronary arteries Left atrium Pulmonary trunk
Copyright © 2010 Pearson Education, Inc. Figure 18.7b Superior vena cava Anterior cardiac veins Small cardiac vein Middle cardiac vein Great cardiac vein Coronary sinus (b) The major cardiac veins
Copyright © 2010 Pearson Education, Inc. Figure 18.4d (d) Posterior surface view Aorta Left pulmonary artery Left pulmonary veins Auricle of left atrium Left atrium Great cardiac vein Posterior vein of left ventricle Left ventricle Apex Superior vena cava Right pulmonary artery Right pulmonary veins Right atrium Inferior vena cava Right coronary artery (in coronary sulcus) Coronary sinus Posterior interventricular artery (in posterior interventricular sulcus) Middle cardiac vein Right ventricle
Copyright © 2010 Pearson Education, Inc. Homeostatic Imbalances Angina pectoris Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium Cells are weakened Myocardial infarction (heart attack) Prolonged coronary blockage Areas of cell death are repaired with noncontractile scar tissue