Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4/e) – Chapter 23

Chapter 23 - The cardiovascular system. After studying this chapter you will be able to: Describe the structure of the heart and the function of each part, trace the flow of blood through the heart. list the most common heart sounds and what events produce them, explain how heart rate is controlled by the electrical conduction system of the heart,...

CHAPTER 23 The Cardiovascular System © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­2 Learning Outcomes 23.1 Describe the structure of the heart and the function of each part 23.2 Trace the flow of blood through the heart 23.3 List the most common heart sounds and what events produce them 23.4 Explain how heart rate is controlled by the electrical conduction system of the heart © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­3 Learning Outcomes (cont.) 23.5 List the different types of blood vessels and describe the functions of each 23.6 Define blood pressure and tell how it is controlled 23.7 Trace the flow of blood through the pulmonary and systemic circulation 23.8 List the major arteries and veins of the body and describe their locations © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­4 Learning Outcomes (cont.) 23.9 List and describe the components of blood 23.10 Give the functions of red blood cells, the different types of white blood cells, and platelets 23.11 List the substances normally found in plasma 23.12 Explain how bleeding is controlled 23.13 Explain the differences among blood types A, B, AB, and O © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­5 Learning Outcomes (cont.) 23.14 Explain the difference between Rh-positive blood and Rh-negative blood 23.15 Explain the importance of blood typing and tell which blood types are compatible 23.16 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­6 Introduction • The cardiovascular system consists of heart and blood vessels • Sends blood to – Lungs for oxygen – Digestive system for nutrients • Also circulates waste products to certain organ systems for removal from the blood © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­7 Structures of the Heart • • • • Cone-shaped organ about the size of a loose fist In the mediastinum Extends from the level of the second rib to about the level of the sixth rib Slightly left of the midline © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­8 Structures of the Heart (cont.)   Heart is bordered:     Laterally by the lungs Posteriorly by the vertebral  column Anteriorly by the sternum Rests on the diaphragm  inferiorly © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­9 Structures of the Heart (cont.) • Heart coverings – Pericardium • • Covers the heart and large blood vessels attached to the heart Visceral pericardium – Innermost layer – Directly on the heart • Parietal pericardium – Layer on top of the visceral pericardium Click for Larger View • Heart walls: – Epicardium • Outermost layer • Fat to cushion heart – Myocardium • Middle layer • Primarily cardiac muscle – Endocardium • Innermost layer • Thin and smooth • Stretches as the heart pumps © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­10 Back © 2011 The McGraw-Hill Companies, Inc All rights reserved Diseases and Disorders of the Cardiovascular System (cont.) Disease 23­54 Description Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg Leukemia Bone marrow produces a large number of abnormal WBCs Murmurs Abnormal heart sounds Myocardial infarction Heart attack; damage to cardiac muscle due to a lack of blood supply © 2011 The McGraw-Hill Companies, Inc All rights reserved Diseases and Disorders of the Cardiovascular System (cont.) Disease 23­55 Description Sickle cell anemia Abnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillaries Thalassemia Inherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCs Thrombophlebi Blood clots and inflammation develop in a tis vein Varicose veins Twisted, dilated veins © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­56 Apply Your Knowledge The doctor has told your patient she has anemia How would you explain this to her? ANSWER: Anemia is a condition in which a person does not have enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to body cells Bravo! © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­57 In Summary 23.1 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 septums are interatrial, interventricular, and atrioventricular – The four valves within the heart are tricuspid, bicuspid, pulmonary semilunar valve, and the aortic semilunar valve © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­58 In Summary (cont.) 23.2 Superior and inferior vena cavae → right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → right and left pulmonary arteries → the lungs → pulmonary veins → left atrium → bicuspid valve →left ventricle → aortic semilunar valve → aorta → body organs and tissues 23.3 Heart sounds are described as lubb dubb Lubb is created when the ventricles contact and the tricuspid and bicuspid valves snap shut Dubb occurs when the atria contract and the pulmonary and aortic semilunar valves snap shut © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­59 In Summary (cont.) 23.4 The sinoatrial node generates an impulse to the atrioventricular node The AV node then sends the impulse to the bundle of His The bundle splits into the left and right bundle branches and sends the impulse to the Purkinje fibers in the ventricles 23.5 The arterial system is composed of the aorta, arteries, and arterioles (largest to smallest) bring blood from the heart to the body The capillaries act as the connectors between the arterioles and venules From the venules, blood returns to the heart via the veins to the superior and inferior vena cavae © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­60 In Summary (cont.) 23.6 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, BP 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 may also raise and lower BP © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­61 In Summary (cont.) 23.7 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→vena cavae→right atrium © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­62 In Summary (cont.) 23.8 The largest artery in the body is the aorta Other major arteries include lingual, facial, occipital, maxillary, ophthalmic, axillary, brachial, ulnar, radial, intercostals, lumbar, external iliac, common iliac, femoral, popliteal, and tibial The largest veins in the body are the superior and inferior vena cavae Other major veins are jugular, brachiocephalic, axillary, brachial, ulnar, radial, intercostals, azygos, gastric, splenic, mesenteric, hepatic portal, hepatic, iliac, femoral, popliteal, and saphenous © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­63 In Summary (cont.) 23.9 The components of blood are red blood cells (RBC), white blood cells (WBC), platelets, and plasma 23.10 Red blood cells carry oxygen and carbon dioxide throughout the body White blood cells are divided into two types: granulocytes and agranulocytes Granulocytes include neutrophils, eosinophils, and basophils Agranulocytes include lymphocytes and monocytes Platelets are essential in the blood clotting process 23.11 Plasma contains three major proteins: albumins, globulins, and fibrinogen © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­64 In Summary (cont.) 23.12 Hemostasis is bleeding control When a blood vessel breaks, the vessel wall spasms and reduces blood loss Platelets stick to the broken area and to each other, forming a platelet plug A blood clot occurs when fibrinogen converts to fibrin, which sticks to the damaged area of the blood vessel, creating a meshwork to trap blood cells and platelets, which will remain while tissues repair themselves © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­65 In Summary (cont.) 23.13 Blood types are named for the antigen present on the cell surfaces The “opposite” letter is the name of the antibody present Blood type A has antigen A and antibody B; blood type B has antigen B and antibody A; blood type AB has antigens A and B and (zero) antibodies; Blood type O has no antigens present and both A and B antibodies 23.14 Rh-positive blood contains the Rh antigen on its RBCs Rh-negative blood carries no such antigen © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­66 In Summary (cont.) 23.15 Due to the antibodies present on different blood types, it is important for blood typing to be done prior to any transfusion It is equally important to know if a patient’s blood type is positive or negative for the same reason A negative blood type will “fight” the positive antigen found on a positive blood type An Rh-negative woman carrying an Rh-positive fetus will develop antibodies against the child’s blood type © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­67 In Summary (cont.) 23.16 Many different types of cardiac and blood diseases are described in this chapter The signs, symptoms, and treatments are as varied as the diseases themselves The Pathophysiology section of this chapter outlines the most common of these diseases, their signs and symptoms, as well as the treatments © 2011 The McGraw-Hill Companies, Inc All rights reserved 23­68 End of Chapter 23 Your work is to  discover your  world and then  with all your heart  give yourself to it.  ~ Buddha © 2011 The McGraw-Hill Companies, Inc All rights reserved ... and back to the heart • Types – Arteries – Arterioles – Veins – Venules – Capillaries © 2011 The McGraw-Hill Companies, Inc All rights reserved 23 23 Arteries and Arterioles • • • Strongest... cardiac cycle – two heart sounds (lubb and dubb) when valves in the heart snap shut – Lubb – first sound • When the ventricles contract, the tricuspid and bicuspid valves snap shut – Dubb – second... (SA node) – – – – Wall of right atrium Generates impulse Natural pacemaker Sends impulse to AV node • Atrioventricular node (AV node) • Bundle of His – Between ventricles – Two branches – Sends