Lecture 10 - Heart and Vessels - The Cardiovascular System PDF

The Cardiovascular System – Heart and Vessels Human Anatomy & Physiology with Pathophysiology Lecture 10 PART 1 Chapter 10 The Cardiovascular System—Heart and Vessels Part 1 Anatomy, Physiology, & Disease...

The Cardiovascular System – Heart and Vessels Human Anatomy & Physiology with Pathophysiology Lecture 10 PART 1 Chapter 10 The Cardiovascular System—Heart and Vessels Part 1 Anatomy, Physiology, & Disease Foundations for the Health Professions Third Edition Deborah Roiger and Nia Bullock © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC. OUTLINE 10.1 Use medical terminology related to the cardiovascular system. 10.2 Identify the chambers, valves, and features of the heart. 10.3 Relate the structure of cardiac muscle to its function. 10.4 Explain why the heart does not fatigue. 10.5 Trace blood flow through the heart. 10.6 Describe the heart’s electrical conduction system. 10.7 Describe the events that produce the heart’s cycle of contraction and relaxation. 10.8 Interpret a normal E K G, explaining what is happening electrically in the heart. 10.9 Calculate cardiac output given heart rate and stroke volume. 10.10 Explain the factors that govern cardiac output. 10.11 Summarize nervous and chemical factors that alter heart rate, stroke volume, and cardiac output. OUTLINE 10.12 Locate and identify the major arteries and veins of the body. 10.13 Compare the anatomy of the three types of blood vessels. 10.14 Describe coronary and systemic circulatory routes. 10.15 Explain how blood in veins is returned to the heart. 10.16 Explain the relationship between blood pressure, resistance, and flow. 10.17 Describe how blood pressure is expressed and how mean arterial pressure and pulse pressure are calculated. 10.18 Explain how blood pressure and flow are regulated. 10.19 Explain the effect of exercise on cardiac output. 10.20 Summarize the effects of aging on the cardiovascular system. 10.21 Describe common diagnostic tests used to diagnose heart and vessel disorders. 10.22 Describe heart and vessel disorders and relate abnormal function to pathology. OVERVIEW The heart serves as a pump to circulate blood through a system of vessels. WORD ROOTS AND COMBINING FORMS arter/o: artery sphygm/o: pulse arteri/o: artery steth/o: chest ather/o: fatty substance tachy/: rapid atri/o: atrium vas/o: vessel brady: slow vascul/o: vessel cardi/o: heart ven/i: vein coron/o: heart ven/o: vein pericardi/o: pericardium ventricul/o: ventricle rhythm/o: rhythm 5 1. THE HEART ANATOMY HEART ANATOMY The heart is located in the mediastinum and is tilted, with two- thirds resting left of the midsagittal plane. The heart is the size of an adult fist weighs approximately 300g, or 10oz. 7 HEART ANATOMY PERICARDIUM The heart is surrounded by the pericardium Outer Fibrous Pericardium Attached to diaphragm, sternum, vertebral column, connective tissues Inner Serous Pericardium Between the two layer is the pericardial cavity Parietal Pericardium Lines fibrous pericardium Visceral pericardium Synonymous with epicardium 8 HEART ANATOMY HEART WALL EPICARDIUM (visceral pericardium) Outermost layer Contains blood vessels that nourish the heart MYOCARDIUM Layer of cardiac muscle Provides force for contraction ENDOCARDIUM Inner layer of simple squamous epithelium Lines inside of blood vessels attached to heart 10 Spiral Arrangement of Cardiac Muscle in the Heart (a, b) Photo and illustration by Roy Schneider, University of Toledo. Heart model courtesy of Dr. Carlos Baptista. 11 HEART ANATOMY CHAMBERS Two ATRIA (Atrium) Receive blood from veins ATRIAL SEPTUM (Interatrial) Two VENTRICLES Pump blood to arteries INTERVENTRICULAR SEPTUM 12  Surface Anatomy of the Heart Christine Eckel/McGraw Hill 13 Internal Anatomy of the Heart Internal Anatomy of the Heart (anterior view) (posterior view) Image Copyright: Christine Eckel 14 HEART ANATOMY VALVES Blood flows in one direction through the heart due to valves. ATRIOVENTRICULAR VALVES Allows flow from atria to ventricles Prevents backflow 1. Tricuspid valve: between R atrium and ventricle 2. Bicuspid valve (Mitral valve): between L atrium and ventricle Chordae tendinae extend from valve cusps to papillary muscles in ventricle walls 15 HEART ANATOMY VALVES SEMILUNAR VALVES Located at base of blood vessels attached to ventricles 1. Pulmonary semilunar valve: between R ventricle and pulmonary trunk 2. Aortic semilunar valve: between L ventricle and aorta 16 HEART ANATOMY CARDIAC MUSCLE TISSUE Cardiac muscle is striated, is branching, has one nucleus per cell, and has intercalated disks. 17 HEART ANATOMY CARDIAC MUSCLE TISSUE Cardiac muscle tissue is specially adapted to stay aerobic. Cardiac muscle cells: Have many very large mitochondria to perform aerobic respiration. Are rich in myoglobin. Are rich in glycogen. Can use a variety of fuels as energy sources (glucose, fatty acids, amino acids, and ketones). 18 1. THE HEART PHYSIOLOGY HEART PHYSIOLOGY BLOOD FLOW THROUGH THE HEART 20 HEART PHYSIOLOGY BLOOD FLOW THROUGH THE HEART Pulmonary Circuit Right side of the heart Pumps blood to the lungs and back Systemic Circuit Left side of the heart Pumps blood to the body, from the heart 21 HEART PHYSIOLOGY CARDIAC CONDUCTION SYSTEM Cardiac muscle is autorhythmic Electrical impulses start at the Sinoatrial (SA) node (pacemaker) Right atria and to the Atrioventricular (AV) node AV bundle and Bundle branches to the Purkinje fibers 22 HEART PHYSIOLOGY Concepts of Volume, Pressure, and Flow CARDIAC CYCLE A cardiac cycle is one complete contraction and relaxation of the heart. Systole is contraction, and diastole is relaxation. Systole increases pressure and decreases volume. Diastole decreases pressure and increases volume. 23 HEART PHYSIOLOGY CARDIAC CYCLE PHASES OF THE CARDIAC CYCLE 1. ATRIAL SYSTOLE 2. ATRIAL DIASTOLE 3. VENTRICULAR SYSTOLE 4. VENTRICULAR DIASTOLE 24 HEART PHYSIOLOGY CARDIAC CYCLE PHASES OF THE CARDIAC CYCLE 1. ATRIAL SYSTOLE SA node fires = atria depolarize Atria contract together Atrial volume decreases Ventricular volume increases 25 HEART PHYSIOLOGY CARDIAC CYCLE PHASES OF THE CARDIAC CYCLE 2. ATRIAL DIASTOLE Atria repolarize together Atria relax Atria fill 26 HEART PHYSIOLOGY CARDIAC CYCLE PHASES OF THE CARDIAC CYCLE 3. VENTRICULAR SYSTOLE Impulse passes through AV node to the Purkinje fibers Ventricles depolarized Ventricles contract together Papillary muscles contract ensuring the AV valves stay closed Ventricular pressure increases – semilunar valves pushes open Ventricles empty Ventricular volume decreases 27 HEART PHYSIOLOGY CARDIAC CYCLE PHASES OF THE CARDIAC CYCLE 4. VENTRICULAR DIASTOLE Ventricles repolarize Ventricles relax Ventricular pressure decreases Ventricular volume increases Ventricles fill 28 HEART PHYSIOLOGY CARDIAC CYCLE HEART SOUNDS DURING THE CARDIAC CYCLE Listened to with a stethoscope Lubb-dupp (pause) lubb-dupp Are caused not by the valves themselves but by the turbulence of the blood when the valves close Lubb: closing of AV valves during ventricular diastole Dupp: closing of semilunar valves during ventricular systole 29 HEART PHYSIOLOGY CARDIAC RHYTHM A normal pace (sinus rhythm) is usually 70 to 80 beats per minute. Vagal tone is braking provided by the parasympathetic nervous system An ectopic focus occurs when any part of the conduction system other than the SA node is setting the pace. A nodal rhythm occurs if the AV node is the ectopic focus. Hypoxemia, caffeine, nicotine, electrolyte imbalance, & some drugs may cause an ectopic focus. An arrhythmia is an abnormal heart rhythm. Heart block, in which one part of the heart’s conduction system fails to send its signals The ventricles may only beat 20 to 40 times per minute 30 HEART PHYSIOLOGY CARDIAC RHYTHM ELECTROCARDIOGRAM An electrocardiogram (ECG or EKG) shows the electrical activity of the heart during a cardiac cycle. It includes P, Q, R, S, and T waves. P wave: atrial depolarization QRS wave: ventricular depolarization T wave: ventricular repolarization 31 The relationship of an ECG and contraction of the myocardium. The purple areas in each drawing (a– g) indicate where tissues are depolarizing, and the green areas indicate where tissues are repolarizing. The graphs next to each drawing show the corresponding portion of the ECG pattern. 32 HEART PHYSIOLOGY CARDIAC OUTPUT The amount of blood ejected by each ventricle of the heart each minute. Dependent on heart rate (HR) and stroke volume (SV). CO = HR × SV Cardiac Reserve Difference between resting cardiac output and maximum cardiac output 33  Arterial Pressure Points HEART PHYSIOLOGY CARDIAC OUTPUT HEART RATE Measured by feeling the pulse Normal heart rate: 64 to 80 bpm (60-100bpm) 34 HEART PHYSIOLOGY CARDIAC OUTPUT STROKE VOLUME Dependent on preload, contractility, and afterload. 1. Preload – amount of stretch of the myocardium Frank-Starling law of the heart 2. Contractility – responsiveness of cardiac muscle to contract 3. Afterload – blood pressure pushing back off the semilunar valves 35 HEART PHYSIOLOGY HEART REGULATION Autonomic Nervous System Two ways: Cardiac Accelerator and Inhibitory Centers in the medulla oblongata Which get information from proprioceptors, baroreceptors, and chemoreceptors. Chronotropic factor – affects heart rate 36 HEART PHYSIOLOGY HEART REGULATION CHRONOTROPIC FACTORS OF THE AUTONOMIC NERVOUS SYSTEM MEDULLA OBLONGATA Cardiac Accelerator Center Sympathetic neurons to stimulate the SA and AV nodes to speed up the heart rate Cardiac Inhibitory Center Parasympathetic neurons of the vagus nerve to keep the SA node at 70 to 80 beats/min (vagal tone) 37 HEART PHYSIOLOGY HEART REGULATION CHRONOTROPIC FACTORS OF THE AUTONOMIC NERVOUS SYSTEM Proprioceptors The information they send alerts the cardiac centers to any change in the body’s activity level. Baroreceptors Located in the aorta and carotid arteries Alert the cardiac centers to any changes in blood pressure. If blood pressure falls, the cardiac accelerator center stimulates the SA and AV nodes to increase the heart rate in an effort to restore blood pressure to homeostasis. 38 HEART PHYSIOLOGY HEART REGULATION CHRONOTROPIC FACTORS OF THE AUTONOMIC NERVOUS SYSTEM Chemoreceptors Sensors monitor pH, carbon dioxide, and oxygen in the blood. Located in the aortic arch, carotid arteries, and medulla oblongata. 39 HEART PHYSIOLOGY HEART REGULATION CHRONOTROPIC FACTORS OF THE AUTONOMIC NERVOUS SYSTEM Epinephrine Positive chronotropic effect Other positive chronotropic chemicals Caffeine Norepinephrine Nicotine Thyroid hormone Potassium ions have a negative chronotropic effect 40 1. THE HEART DISORDERS DISORDERS OF THE HEART VALVE DISORDERS A murmur is an abnormal heart sound Functional (not a problem) Pathological (possible leaky valve) A prolapsed valve A valve leaflet that “billows”, or bends in a way that prevents it from closing properly Can be caused by degeneration of the valve or the chordae tendineae Mitral valve prolapse is most common type 42 DISORDERS OF THE HEART MYOCARDIAL DISORDERS Myocardial infarction is the death of myocardial tissue fed by the affected artery due to ischemia (lack of blood flow). Commonly called a heart attack Angina pectoris is a heaviness or pain in the chest caused by temporary or reversible myocardial ischemia Hypoxemia from reduced blood flow Lactic acid buildup causes chest pain 43 DISORDERS OF THE HEART MYOCARDIAL DISORDERS Congestive heart failure occurs when one ventricle is not as efficient as the other ventricle. Blood pressure builds in the circuit before the ventricle, resulting in edema. Pulmonary Edema Systemic Edema 44 Left-sided Heart Failure → Pulmonary Edema Right-sided Heart Failure → Systemic Edema 45 FETAL CIRCULATION DISORDERS OF THE HEART CONGENITAL HEART DEFECTS Patent Ductus Arteriosus (PDA) Incomplete closure of the ductus arteriosus after birth Atrial Septal Defect (ASD) Hole in the septum dividing the right and left atrium Ventricular Septal Defect (VSD) Hole in the septum dividing the right and left ventricle Tetralogy of Fallot (TOF) 1. Pulmonary valve stenosis 2. VSD 3. Overriding aorta 4. Right ventricular hypertrophy. 47 Tetralogy of Fallot 48 The Cardiovascular System – Heart and Vessels Human Anatomy & Physiology with Pathophysiology Lecture 10 PART 2 Chapter 10 The Cardiovascular System—Heart and Vessels Part 2 Anatomy, Physiology, & Disease Foundations for the Health Professions Third Edition Deborah Roiger and Nia Bullock © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC. 2. THE VESSELS ANATOMY VESSEL ANATOMY Arteries carry blood away from the heart to capillaries. Capillaries allow for the exchange of materials between the blood and tissues. Veins deliver blood from the capillaries back to the heart. 52 The Major Systemic Arteries The Major Systemic Veins 53 VESSEL ANATOMY Structural Differences of Arteries and STRUCTURE OF ARTERIES AND Veins VEINS TUNICA EXTERNA Fibrous connective tissue Provide support and elasticity TUNICA MEDIA Smooth muscle fibers Cause changes in blood vessel diameter TUNICA INTERNA Endothelium lining inside of blood vessel 54 Arteriole and Venule Al Telser/McGraw Hill Education 55 VESSEL ANATOMY A. ARTERIES CONDUCTING ARTERIES DISTRIBUTING ARTERIES RESISTANCE ARTERIES Largest of the arteries These arteries are medium- These are the smallest of the size. arteries. Pulmonary arteries, the aorta, and the common Distribute blood from the Examples are the small carotid arteries conducting arteries to organs arterioles that deliver blood to the capillaries. Withstand the high pressure Examples: the hepatic artery generated by ventricular and the renal arteries Arterioles have little, if any, systole elastic fibers. Have some elastic fibers in Have the most muscle and their walls to hold their Each arteriole can feed a bed of shape, but they do not need approximately 100 capillaries. elastic fibers in their walls so that they can expand with to expand as much as Precapillary sphincters (circular each heartbeat and then conducting arteries with muscles) in the arterioles open or close to return to shape every heartbeat regulate blood flow to the capillaries. 56 VESSEL ANATOMY 57 VESSEL ANATOMY B. CAPILLARIES Capillaries are the site of exchange of materials between the blood and tissues. Most numerous and smallest vessels RBCs pass through one at a time. Walls of endothelium thin enough to allow exchange of materials between blood and cells Most abundant in active tissues Less abundant in connective tissues 58 VESSEL ANATOMY C. VEINS Veins return blood back to the heart. Blood flows from capillaries into venules. Venules unite to form medium veins, which in turn unite to form large veins. Valves exist in large veins to prevent blood backflow and aid in venous blood return. 59 2. THE VESSELS PHYSIOLOGY VESSEL PHYSIOLOGY CIRCULATORY ROUTES A. Coronary Route B. Systemic Route C. Alternative Routes 61 VESSEL PHYSIOLOGY CIRCULATORY ROUTES A. CORONARY ROUTE → supplies blood to the heart. Anterior view Posterior view 62 Polymer Cast of Coronary Circulation (c) Martin Dohrn/Royal College of Surgeons/Science Source 63 VESSEL PHYSIOLOGY Pulmonary Circulation CIRCULATORY ROUTES B. SYSTEMIC ROUTE → typically includes one capillary bed. Heart → Arteries → Capillaries → Veins → Heart 64  Hepatic Portal Route VESSEL PHYSIOLOGY CIRCULATORY ROUTES C. ALTERNATIVE ROUTES vary in the number of capillary beds or involve the merging of vessels. Two types 1. PORTAL 2. ANASTOMOSIS 1. PORTAL ROUTES Heart → arteries → capillaries → intervening vessels → capillaries → veins → heart Example: Hepatic portal route 65 VESSEL PHYSIOLOGY CIRCULATORY ROUTES 2. ANASTOMOSES A. ARTERIOVENOUS ANASTOMOSES This type of route is often called a shunt. Capillary bed is skipped. B. ARTERIAL ANASTOMOSES Two arteries provide collateral routes to the same area. Around joints Heart and brain C. VENOUS ANASTOMOSES Merging veins to drain in organ 66 VESSEL PHYSIOLOGY The Skeletal Muscle Pump VENOUS RETURN Blood is returned to the heart through veins by five mechanisms: Pressure gradient Gravity Thoracic pump Cardiac suction Skeletal muscle pump Limbs Skeletal muscle action massages blood through the veins, while the valves in the veins prevent backflow. 67 VESSEL PHYSIOLOGY BLOOD PRESSURE, RESISTANCE, AND FLOW Blood flow is the amount of blood flowing to an area in a given amount of time. Blood pressure is the force of blood against the vessel walls. Blood pressure is dependent on cardiac output, blood volume, and resistance. 68 VESSEL PHYSIOLOGY THREE FACTORS IN RESISTANCE 1. BLOOD VISCOSITY (THICKNESS) Thicker blood offers more resistance to flow and requires more pressure to get it to move. 2. VESSEL LENGTH The greater the vessel length, the more friction occurs between the blood and the vessel walls. 3. VESSEL RADIUS Vessel radius becomes a factor because the smaller the radius, the more blood comes in contact with the walls of the vessel. 69 VESSEL PHYSIOLOGY BLOOD PRESSURE, RESISTANCE, AND FLOW Blood pressure is measured as systolic pressure/diastolic pressure with the sphygmomanometer Pulse pressure = systolic pressure – diastolic pressure. Mean arterial pressure MAP = diastolic pressure + 1/3 pulse pressure. 70 VESSEL PHYSIOLOGY REGULATION OF BLOOD PRESSURE AND FLOW Blood pressure and flow can be regulated: A. Locally B. Hormonally C. Neurally 71 VESSEL PHYSIOLOGY REGULATION OF BLOOD PRESSURE AND FLOW A. LOCAL CONTROL Opening of precapillary sphincters Controlled by waste product and nutrient levels Inflammation Basophils release vasodilators Reactive hyperemia Overdilation following lack of blood Angiogenesis Growth of new vessels 72 VESSEL PHYSIOLOGY REGULATION OF BLOOD PRESSURE AND FLOW B. HORMONAL CONTROL ADH (also called vasopressin) Increases blood volume and blood pressure Aldosterone Increases sodium ions and causes water retention increase in the effects of A D H Angiotensin II Potent vasoconstrictor which increases resistance and blood pressure Epinephrine Vasoconstriction increases blood pressure 73 VESSEL PHYSIOLOGY REGULATION OF BLOOD PRESSURE AND FLOW C. NEURAL CONTROL Baroreflex High blood pressure stretches carotid arteries triggering a reflex that decreases blood pressure. Chemoreflex High carbon dioxide or acid levels trigger vasoconstriction and increase blood pressure. Medullary ischemic reflex A direct monitor of cerebral blood pressure Increases blood pressure, and blood flow reduces to the brain 74 VESSEL PHYSIOLOGY EFFECTS OF EXERCISE ON CARDIAC OUTPUT Exercise increases cardiac output by raising the heart rate and the stroke volume. Heart muscle becomes stronger. Stroke volume is higher at rest. Heart rate is slower at rest. 75 EFFECTS OF AGING ON THE CARDIOVASCULAR SYSTEM If blood pressure remains normal throughout life, age-related changes to the cardiovascular system may be minimal. If an individual is hypertensive, age-related changes may include an increase in vascular resistance, decreased stroke volume, and thicker, less elastic vessels that are prone to atherosclerosis. Lifestyle choices like exercising, dieting, and not smoking can make a difference. 76 2. THE VESSELS DIAGNOSTICS TESTS DIAGNOSTIC TESTS FOR HEART AND VESSEL DISORDERS ASSESS PHYSIOLOGY OF HEART AND ANATOMY Echocardiography uses sound waves to create a picture of the heart Electrocardiography evaluates the electrical activity of the heart Heart CT Scan is computerized tomography of the heart Nuclear Heart Scan uses radioactive dye to view the heart 78 DIAGNOSTIC TESTS FOR HEART AND VESSEL DISORDERS ASSESS CARDIAC FUNCTION DURING ACTIVITY Holter Monitor is a machine continuously worn by the patient to monitor heart rhythms during everyday activity Stress Test monitors the heart’s electrical activity, blood pressure, and heart rate while the patient is exercising. 79 DIAGNOSTIC TESTS FOR HEART AND VESSEL DISORDERS VISUALIZE CORONARY VESSELS, ARTERIES AND VEINS Cardiac catheterization uses contrast dye to examine the movement of the dye through the valves, heart chambers, and coronary arteries. The dye movement is viewed by X-ray. CT Angiography is a noninvasive way to perform coronary angiography using a CT scan. Ultrasound uses sound waves to visualize internal structures Venography uses contrast dye examined under X-ray to view blood vessels. 80 2. THE VESSELS DISORDERS DISORDERS OF THE VESSELS VESSEL DISORDERS ATHEROSCLEROSIS is buildup of fatty deposits (plaque) within arterial walls Obstructs blood flow If the fatty deposit becomes calcified, the condition is called arteriosclerosis CORONARY ARTERY DISEASE (CAD) results when the atherosclerosis or arteriosclerosis obstructs the coronary arteries that supply blood to the heart. Image Copyright: Ed Reschke 82 DISORDERS OF THE VESSELS VESSEL DISORDERS THROMBOPHLEBITIS is inflammation of a vein caused by thrombosis (formation of a blood clot in a blood vessel) DEEP VENOUS THROMBOSIS (DVT) affects deep veins Can result in a pulmonary embolism (a blood clot that has traveled to the lungs) SUPERFICIAL THROMBOPHLEBITIS affects veins close to the skin's surface (b) DIGIcal/E+/Getty Images 83 DISORDERS OF THE VESSELS VESSEL DISORDERS VARICOSE VEINS are veins in which the valves that prevent backflow of blood are not working properly. Allows blood to pool Causes vein to enlarge 84 Because learning changes everything. ® www.mheducation.com © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.