After studying this chapter you will be able to: Describe the structure of the heart and the function of each; explain the cardiac cycle, including the cardiac conduction system; compare pulmonary and systemic circulation; differentiate among the different types of blood vessels and their functions;...
CHAPTER 26 The Cardiovascular System 26-2 Learning 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 26-3 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 26-4 Introduction • The cardiovascular system – Heart Blood vessels – Sends blood to – • Lungs for oxygen • Digestive system for nutrients – Also circulates waste products for removal 26-5 The Heart • Cone-shaped organ • Size of a loose fist • Slightly left of the midline • Bordered by – Lungs – Sternum and vertebral column – Diaphragm 26-6 Cardiac Membranes • Pericardium – Covers the heart and large blood vessels – Fibrous outer layer – Visceral pericardium ~ epicardium – Parietal pericardium • Pericardial sac • Pericardial cavity – pericardial fluid Cardiac Membranes 26-8 The Heart Wall • Epicardium • Myocardium • Endocardium – Thin, smooth layer – Contains part of electrical conduction system Heart Wall 26-9 Heart Chambers and Valves • Four chambers – Two atria • Upper chambers • Interatrial septum – Two ventricles • • Lower chambers Interventricular septum – Atrioventricular septum separates the atria from the ventricles Click for View of Heart 26-10 Heart Chambers and Valves (cont.) • Valves between atria and ventricles – Tricuspid ~ three cusps – Bicuspid ~ two cusps • Valves between ventricles and arteries – Pulmonary semilunar – Aortic semilunar Click for View of Heart 26-12 Apply Your Knowledge Match the following: ANSWER: C Tricuspid valve A Outermost layer of the heart wall F Bicuspid valve B Covering of the heart and aorta H Intraventricular septum C Between the right atrium and the right ventricle D Ventricles D Pump blood into the arteries B Pericardium E Primarily cardiac muscle A Epicardium F Between the left atrium and the left ventricle E Myocardium G Inner most layer of the heart wall G Endocardium H Separates the ventricles 26-34 Blood Pressure (cont.) • Baroreceptors – Help regulate blood pressure – Located in the aorta and carotid arteries – Send information to cardiac center in the medulla oblongata 26-35 Apply Your Knowledge What 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 System • Chest pain – Cardiac causes • • • • Myocardial infarction Angina Pericarditis Coronary spasm Take all complaints of chest pain seriously! – Non-cardiac causes • • • • • • • Heartburn Panic attacks Pleurisy Costochondritis Pulmonary embolism Sore muscles Broken ribs 26-36 Diseases and Disorders of the Cardiovascular System (cont.) Disease Aneurysm Description A ballooned, weakened arterial wall Arrhythmias Abnormal heart rhythms Inflammation of the innermost lining Endocarditis of the heart, including valves Myocarditis Inflammation of the muscular layer of the heart 26-37 Diseases and Disorders of the Cardiovascular System (cont.) Disease Pericarditis Description Inflammation of the membranes that surround the heart (pericardium) Congestive Weakening of the heart over time; heart failure heart is unable to pump enough blood to meet body’s needs Coronary artery disease (CAD) Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within them 26-38 Diseases and Disorders of the Cardiovascular System (cont.) Disease Description Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg Mitral valve prolapse Valve falls into the left atrium during systole; prevents proper closing Murmurs Abnormal heart sounds 26-39 Diseases and Disorders of the Cardiovascular System (cont.) Disease Description Myocardial infarction Heart attack; damage to cardiac muscle due to a lack of blood supply Stenosis of the heart valves The valve does not fully open; aortic stenosis, mitral stenosis Thrombophlebitis Blood clots and inflammation develop in a vein Varicose veins Twisted, dilated veins 26-40 26-41 Apply Your Knowledge ANSWER: True or false: T A myocardial infarction results from a lack of F oxygen to the cardiac muscle Myocarditis is inflammation of the innermost Endocarditis T lining of the heart A potentially fatal arrhythmia is ventricular sounds F fibrillation Murmurs are abnormal heart rhythms Bravo! 26-42 In Summary 26.1 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 26-43 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 26-44 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 26-45 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 26-46 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 26-47 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 26-48 End of Chapter 26 Your work is to discover your world and then with all your heart give yourself to it ~ Buddha ... is controlled 26. 6 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system 26- 4 Introduction • The cardiovascular system – Heart.. .26- 2 Learning 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... Compare pulmonary and systemic circulation 26- 3 Learning Outcomes (cont.) 26. 4 Differentiate among the different types of blood vessels and their functions 26. 5 Explain blood pressure and tell how