Y khoa - Dược - Chapter 26: The cardiovascular system

26The Cardiovascular SystemLearning Outcomes (cont.)26.1 Describe the structures of the heart and the function of each. 26.2 Explain the cardiac cycle, including the cardiac conduction system.26.3 Compare pulmonary and systemic circulation.Learning Outcomes (cont.)26.4 Differentiate among the different types of blood vessels and their functions. 26.5 Explain blood pressure and tell how it is controlled. 26.6 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system. Introduction The cardiovascular system Heart Blood vesselsSends blood toLungs for oxygenDigestive system for nutrientsAlso circulates waste products for removalThe HeartCone-shaped organ Size of a loose fistSlightly left of the midlineBordered byLungsSternum and vertebral columnDiaphragmCardiac MembranesPericardium Covers the heart and large blood vesselsFibrous outer layerVisceral pericardium ~ epicardium Parietal pericardiumPericardial sacPericardial cavity – pericardial fluid Cardiac MembranesBackCardiac Membranes (cont.)The Heart Wall Epicardium Myocardium EndocardiumThin, smooth layerContains part of electrical conduction systemHeart WallHeart Chambers and ValvesFour chambersTwo atriaUpper chambersInteratrial septumAtrioventricular septum separates the atria from the ventriclesTwo ventriclesLower chambersInterventricular septumClick for View of HeartHeart Chambers and Valves (cont.) Valves between atria and ventriclesTricuspid ~ three cuspsBicuspid ~ two cuspsValves between ventricles and arteriesPulmonary semilunar Aortic semilunar Click for View of HeartThe Heart LabeledBackApply Your KnowledgeMatch the following:__ Tricuspid valve A. Outermost layer of the heart wall __ Bicuspid valve B. Covering of the heart and aorta__ Intraventricular C. Between the right atrium and the right  septum ventricle Ventricles D. Pump blood into the arteries Pericardium E. Primarily cardiac muscle Epicardium F. Between the left atrium and the left ventricle Myocardium G. Inner most layer of the heart wall Endocardium H. Separates the ventriclesBFCANSWER:ADEGHCardiac CycleOne heart beat = one cardiac cycleRight atrium contracts  tricuspid valve opens  blood flows into right ventricleLeft atrium contracts  bicuspid valve closes  blood flows into left ventricleCardiac Cycle (cont.)Right ventricle contracts  tricuspid valve closes  pulmonary semilunar valve opens  blood is pushed into pulmonary arteryLeft ventricle contacts  bicuspid valve closes  aortic semilunar valve opens  blood is pushed into aortaCardiac Cycle (cont.)Influenced byExerciseParasympathetic nervesSympathetic nervesCardiac control centerBody temperaturePotassium ionsCalcium ionsHeart SoundsLubb First soundOccurs when ventricles contract and the tricuspid and bicuspid valves snap shut Dubb Second sound Occurs when atria contract and the pulmonary and aortic valves snap shut Murmur – abnormal heart soundClick for Heart SoundsCardiac Conduction SystemSinoatrial node Right atriumNatural pacemakerSends impulse to AV nodeAtrioventricular node Between atria and just above ventriclesSends impulse to the bundle of HisClick for Conduction SystemCardiac Conduction System (cont.)Bundle of HisBetween ventriclesRight and left bundle branchesSends impulse to Purkinje fibersPurkinje fibersLateral walls of ventriclesVentricles contractClick for Conduction SystemBackCardiac Conduction System (cont.)Apply Your KnowledgeSmashing!Match the following:__ Right ventricle A. Two branches; sends impulse to Purkinje  fibers__ Left ventricle B. Located in the medulla oblongata__ Cardiac control C. Contraction pushes blood into the lungs center __ SA node D. In the lateral walls of ventricles__ Bundle of His E. Natural pacemaker__ Purkinje fibers F. Contraction sent blood to the aortaDAEBFCANSWER:CirculationPulmonary circulationOxygenates bloodRemoves carbon dioxideSystemic CirculationDelivers oxygen and nutrients Removes carbon dioxide and waste productsLungsCirculation (cont.)Right AtriumRight VentricleLeft AtriumBicuspidValveLeft VentriclePulmonary SemilunarValveTricuspidValveBodyAorticSemilunarValvePulmonary CirculationSystemic CirculationApply Your KnowledgeWhat are the functions of the pulmonary and systemic circulations?ANSWER: The pulmonary circulation functions to oxygenate the blood and remove carbon dioxide. The systemic circulation delivers oxygen and nutrients to and removes carbon dioxide and waste products from the body’s cells.Correct!Blood VesselsForm a closed pathway that carries blood from the heart to cells and back to the heartArteries and Arterioles Thick muscular wallCarry blood under high pressureArteriolesCoronary arteries Supply heart muscleCoronary sinusPulmonary arteriesHeart to lungsDeoxygenated bloodAorta Veins and Venules VeinsDeoxygenated bloodSkeletal muscle contractions move bloodValves prevent back flowSympathetic nervous system effectVeins and Venules Venules Pulmonary veins – oxygenated bloodSuperior and inferior vena cavaHepatic portal systemCapillariesBranches of arteriolesConnect arterioles to venulesExchange vesselsOxygen and nutrients Carbon dioxide and waste products Water Apply Your KnowledgeARTERIES:Match the following: coronary arteries A. exchange vessels arterioles B. supply blood to the heart tissues veins C. largest veins in the body arteries D. supplies the forearm and hand capillaries E. carry blood toward heart vena cavae F. drain the knees radial artery G. strongest blood vessels popliteal veins H. small branches of arteriesYIPPEE!CABDEFGHBlood PressureThe force blood exerts on the inner walls of blood vesselsHighest in arteries Lowest in veinsRises and falls as ventricles contract and relax Blood PressureSystolic pressure Systole Ventricles contractBlood pressure in arteries greatestDiastolic pressureDiastoleVentricles relaxBlood pressure in arteries lowestPulseBlood Pressure (cont.)Factors affecting blood pressure Cardiac output Blood volumeVasoconstriction and vasodilationBlood viscosity Blood Pressure (cont.)Controlled by the amount of blood pumped out of the heart Starling's law of the heart Blood entering the left ventricle stretches its wallThe more the wall is stretched the harder it will contractBlood Pressure (cont.)Baroreceptors Help regulate blood pressureLocated in the aorta and carotid arteriesSend information to cardiac center in the medulla oblongataApply Your KnowledgeWhat is the difference between the systolic pressure and diastolic pressure?ANSWER: Systolic pressure is the result of the contraction of the ventricles increasing the pressure in the arteries. Diastolic pressure is the result of the relaxation of the ventricles lowering the pressure in the arteries.Diseases and Disorders of the Cardiovascular SystemChest pain Cardiac causesMyocardial infarctionAnginaPericarditisCoronary spasmNon-cardiac causesHeartburnPanic attacksPleurisyCostochondritis Pulmonary embolismSore musclesBroken ribsTake all complaints of chest pain seriously!Diseases and Disorders of the Cardiovascular System (cont.)DiseaseDescriptionAneurysm A ballooned, weakened arterial wall ArrhythmiasAbnormal heart rhythmsEndocarditisInflammation of the innermost lining of the heart, including valvesMyocarditisInflammation of the muscular layer of the heartDiseases and Disorders of the Cardiovascular System (cont.)DiseaseDescriptionPericarditisInflammation of the membranes that surround the heart (pericardium)Congestive heart failureWeakening of the heart over time; heart is unable to pump enough blood to meet body’s needsCoronary artery disease (CAD)Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within themDiseases and Disorders of the Cardiovascular System (cont.)DiseaseDescriptionHypertensionHigh blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm HgMitral valve prolapseValve falls into the left atrium during systole; prevents proper closingMurmurs Abnormal heart soundsDiseases and Disorders of the Cardiovascular System (cont.)DiseaseDescriptionMyocardial infarctionHeart attack; damage to cardiac muscle due to a lack of blood supplyStenosis of the heart valves The valve does not fully open; aortic stenosis, mitral stenosis ThrombophlebitisBlood clots and inflammation develop in a veinVaricose veinsTwisted, dilated veins Apply Your KnowledgeANSWER:True or false: A myocardial infarction results from a lack of  oxygen to the cardiac muscle Myocarditis is inflammation of the innermost  lining of the heart. A potentially fatal arrhythmia is ventricular  fibrillation. Murmurs are abnormal heart rhythms.Bravo!TTFFEndocarditissoundsIn Summary26.1 The structures of the heart include the pericardium, epicardium, myocardium, and endocardium. The chambers of the heart consist of the upper atria and the lower ventricles. The septa are the interatrial, interventricular, and atrioventricular. The four valves within the heart are the tricuspid, the bicuspid, the pulmonary semilunar, and the aortic semilunar valves. In Summary (cont.)26.2 One cardiac cycle consists of one complete heartbeat. The atria contract and relax together, and the ventricles contract and relax together. As each chamber contracts, associated valves open and close to control the flow of blood through the heart. Contractions are initiated by the cardiac conduction system.In Summary (cont.)26.3 Pulmonary circulation: Right atrium  tricuspid valve  right ventricle  pulmonary semilunar valve pulmonary trunk  pulmonary arteries  lungs pulmonary veins  left atrium. Systemic circulation: Left atrium  bicuspid valve left ventricle  aortic semilunar valve  aorta  arteries  arterioles  capillaries  venules  veins  venae cavae  right atrium. In Summary (cont.)26.4 Types of blood vessels include arteries and arterioles, which bring blood from the heart to the body; capillaries, which act as the connectors between the arterioles and venules. The largest artery in the body is the aorta. Others arteries are listed in the chapter. The largest veins in the body are the superior and inferior venae cavae. Others veins are listed in the chapter.In Summary (cont.)26.5 Blood pressure is the force exerted on the inner wall of blood vessels by blood as it flows through vessels. It is highest in arteries and lowest in veins. Clinically, blood pressure refers to the force of blood within the arteries. Blood pressure is largely controlled by the amount of blood pumped out of the heart, but various other events also may raise and lower blood pressure. In Summary (cont.)26.6 Many different types of cardiac and blood diseases are described within this chapter. The signs, symptoms, and treatments are as varied as the diseases themselves. The last section of this chapter outlines the most common of these diseases, their signs and symptoms, as well as their treatments. Your work is to discover your world and then with all your heart give yourself to it. ~ BuddhaEnd of Chapter 26