Structure and Function of the Cardiovascular and Lymphatic

Structure and Function of the Cardiovascular and Lymphatic Systems Chapter 29 1

Circulatory System o Heart n Right heart o n Pumps blood through the lungs (pulmonary circulation) Left heart o Pumps blood through the systemic circulation 2 Mosby items and derived items © 2006 by Mosby, Inc.

Circulatory System Pulmonary circuit has deoxygenated blood, Systemic circuit has oxygenated blood. Veins conduct blood to the heart and arteries conduct blood away from heart 3 Mosby items and derived items © 2006 by Mosby, Inc.

Circulatory System o Heart n n Mediastinum Heart wall o Pericardium n n o o Parietal and visceral pericardium Pericardial cavity and fluid – fluid-filled space Myocardium – the thick contractile muscle layer Endocardium – inner lining of the heart, smooth 4 Mosby items and derived items © 2006 by Mosby, Inc.

The Heart Wall 5 Mosby items and derived items © 2006 by Mosby, Inc.

The Chambers of the Heart o o Right atrium – receiving chamber for blood from systemic side. No valve between vena Cava and R atrium Left atrium – receiving deox blood from lungs Right ventricle – pumps blood to lungs via pulmonary arteries Left ventricle – pumps blood to systemic circuit via aortia 6 Mosby items and derived items © 2006 by Mosby, Inc.

The Chambers of the Heart 7 Mosby items and derived items © 2006 by Mosby, Inc.

The Valves of the Heart o Atrioventricular valves between A & V n n o Tricuspid valve – Right side Bicuspid valve – left side Semilunar valves n n Pulmonic semilunar valve Aortic semilunar valve Valves and other connective tissue do not conduct electrical impulses and make up heart skeleton 8 Mosby items and derived items © 2006 by Mosby, Inc.

The Valves of the Heart 9 Mosby items and derived items © 2006 by Mosby, Inc.

The Great Vessels o o Superior and inferior venae cavae – bring blood to R Ventricle from head & body Pulmonary artery (trunk) - blood to lungs n o o Right and left pulmonary arteries Pulmonary veins – blood from lungs Aortia – conducts blood to systemic circuit 10 Mosby items and derived items © 2006 by Mosby, Inc.

Blood Flow o o Cardiac cycle – the electrical and physical events of an entire heart beat – 0. 7 seconds Diastole – resting phase – no active contraction Systole – active muscle contraction and electrical impulses Phases of the cardiac cycle 11 Mosby items and derived items © 2006 by Mosby, Inc.

Blood Flow 12 Mosby items and derived items © 2006 by Mosby, Inc.

Normal Intracardiac Pressures 13 Mosby items and derived items © 2006 by Mosby, Inc.

Normal Intracardiac Pressures 14 Mosby items and derived items © 2006 by Mosby, Inc.

The Coronary Vessels only 2 arteries with little collateral circulation o Right coronary artery blood flows into artery only after aortic semilunar valve is closed otherwise the opening is covered by valve n n n o Conus Right marginal branch Posterior descending branch Left coronary artery n n Left anterior descending artery Circumflex artery 15 Mosby items and derived items © 2006 by Mosby, Inc.

The Coronary Vessels o o o Collateral arteries Coronary capillaries Coronary veins n n n o Coronary sinus Great cardiac vein Posterior vein of the left ventricle Coronary lymphatic vessels 16 Mosby items and derived items © 2006 by Mosby, Inc.

The Coronary Vessels 17 Mosby items and derived items © 2006 by Mosby, Inc.

Structures That Control Heart Action o o Cardiac action potentials – electric stimulation of the heart Conduction system – specialized muscle cells that depolarize on their own called pacemakers – little muscle actin & myosin n Sinoatrial node (SA) – pacemakers depolarize 100 x /minutes due to leaky membranes to Na o n n Intranodal pathways Atrioventricular node (AV) – only electrical connection between Atria (top) and Ventricles (bottom) of heart Bundle of His (AV bundle) – pass through septum of heart to apex Right and left bundle branches spread out to muscle of ventricles Purkinje fibers – into the larger muscle mass 18 Mosby items and derived items © 2006 by Mosby, Inc.

Conduction System of the Heart 19 Mosby items and derived items © 2006 by Mosby, Inc.

Structures That Control Heart Action o o Cardiac excitation Propagation of cardiac action potentials n n o o o Depolarization Repolarization – long refractory period Electocardiogram – EKG Automaticity Rhythmicity 20 Mosby items and derived items © 2006 by Mosby, Inc.

Structures That Control Heart Action o Cardiac innervation n n o Sympathetic nerves Parasympathetic nerves Adrenergic receptor function n n α- or β-adrenergic receptors Norepinephrine or epinephrine 21 Mosby items and derived items © 2006 by Mosby, Inc.

Autonomic Innervation of the Cardiovascular System 22 Mosby items and derived items © 2006 by Mosby, Inc.

Myocardial Cells o o o Nearly identical to skeletal muscle cells Intercalated disks Actin, myosin, and the troponin-tropomyosin complex n o Troponin T, I, and C Myocardial metabolism n Myocardial oxygen consumption 23 Mosby items and derived items © 2006 by Mosby, Inc.

Myocardial Contraction and Relaxation 24 Mosby items and derived items © 2006 by Mosby, Inc.

Cardiac Performance o o o Preload Afterload Frank-Starling law of the heart – self regulating mechanism that controls stroke volume and force. The greater the stretch of the heart muscle the stronger the force of contraction up to a maximum n o End-diastolic volume – measure of the return flow of blood and stretch of the ventricles Laplace law 25 Mosby items and derived items © 2006 by Mosby, Inc.

Cardiac Performance o Heart rate n Cardiovascular control center – in medula o n Neural reflexes o n n Cardioexcitatory and cardioinhibitory centers Bainbridge and baroreceptor reflexes Atrial receptors – sense the stretch (refill) of heart Hormones and biochemicals – epinephrine, digitalis etc… 26 Mosby items and derived items © 2006 by Mosby, Inc.

Cardiac Performance o Myocardial contractility n n n o Stroke volume = SV Inotropic agents Oxygen and carbon dioxide levels Cardiac output CO = SV x HR n Volume of blood flowing through either the systemic or pulmonary circuit in liters per minute 27 Mosby items and derived items © 2006 by Mosby, Inc.

Cardiac Output 28 Mosby items and derived items © 2006 by Mosby, Inc.

Systemic Circulation o o o Arteries Arterioles Capillaries Venules Veins 29 Mosby items and derived items © 2006 by Mosby, Inc.

Structure of Blood Vessels o o Lumen Tunica intima Tunica media Tunica externa (adventitia) 30 Mosby items and derived items © 2006 by Mosby, Inc.

Endothelium 31 Mosby items and derived items © 2006 by Mosby, Inc.

Structure of Blood Vessels 32 Mosby items and derived items © 2006 by Mosby, Inc.

Factors Affecting Blood Flow o o Poiseuille law effect of diameter & length of vessel on resistance Pressure n o Force exerted on a liquid per unit area Resistance n n Opposition to force Diameter and length of the blood vessels contribute to resistance 33 Mosby items and derived items © 2006 by Mosby, Inc.

Factors Affecting Blood Flow o Neural control of total peripheral resistance n n n Change in diameter of the vessels Baroreceptors Arterial chemoreceptors 34 Mosby items and derived items © 2006 by Mosby, Inc.

Baroreceptor and Chemoreceptors 35 Mosby items and derived items © 2006 by Mosby, Inc.

Factors Affecting Blood Flow o o o Velocity Laminar vs. turbulent flow Vascular compliance 36 Mosby items and derived items © 2006 by Mosby, Inc.

Laminar vs. Turbulent Flow 37 Mosby items and derived items © 2006 by Mosby, Inc.

Regulation of Blood Pressure o Arterial pressure n n n Mean arterial pressure (MAP) Effects of cardiac output Effects of total peripheral resistance Effect of hyperemia Effects of hormones o o Epinephrine and norepinephrine Antidiuretic hormone, renin-angiotensin system, and natriuretic peptides 38 Mosby items and derived items © 2006 by Mosby, Inc.

Regulation of Blood Pressure o o o Adrenomedullin Insulin Venous pressure 39 Mosby items and derived items © 2006 by Mosby, Inc.

Regulation of Coronary Circulation o o o Coronary perfusion pressure Autoregulation Autonomic regulation 40 Mosby items and derived items © 2006 by Mosby, Inc.

Lymphatic System o o o Special vascular system that picks up excess fluid and returns it to the bloodstream Lymphatic fluid Lymphatic veins and venules Right lymphatic duct Thoracic duct Afferent and efferent lymphatic vessels 41 Mosby items and derived items © 2006 by Mosby, Inc.

Lymphatic System 2 main locations for fluid return to blood – R Lymphatic duct & Thoracic duct on L subclavian Vein 42 Mosby items and derived items © 2006 by Mosby, Inc.

Tests of Cardiovascular Function o Noninvasive assessments n n n Sensorium of the individual Mucous membrane color Manually palpated pulse Auscultation of heart sounds Cardiography 43 Mosby items and derived items © 2006 by Mosby, Inc.

Tests of Cardiovascular Function o Noninvasive assessments n n n Pulse tracing Magnetic resonance imaging Doppler studies Stress testing Chest x-ray examinations 44 Mosby items and derived items © 2006 by Mosby, Inc.

Tests of Cardiovascular Function o Invasive assessments n n X-ray films with barium Nuclear imaging with radiolabeled pharmaceuticals o o n Hot spot imaging Cold spot imaging Tomographic studies 45 Mosby items and derived items © 2006 by Mosby, Inc.

Tests of Cardiovascular Function o Invasive assessments n n n Atrioventricular bundle electrocardiography Cardiac catheterization Coronary angiography 46 Mosby items and derived items © 2006 by Mosby, Inc.

Aging and the Cardiovascular System o Arteriosclerosis n n n o Cross linking of collagen Increased collagen Changes in elastin Atherosclerosis 47 Mosby items and derived items © 2006 by Mosby, Inc.

Aging and the Cardiovascular System 48 Mosby items and derived items © 2006 by Mosby, Inc.