1.  INTRODUCTION AND QUESTIONS  REVIEW OF CIRCULATORY SYSTEM  PLAYING FOR KUDOS Slide 1 Unit 2

2. Chapter 12 The Circulatory System

3. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 3 Location, size, and position Triangular organ located in mediastinum with two thirds of the mass to the left of the body midline and one third to the right; the apex on the diaphragm; shape and size of a closed fist (Figure 12-1) Cardiopulmonary resuscitation (CPR)—the heart lies between the sternum in front and the bodies of the thoracic vertebrae behind; rhythmic compression of the heart between the sternum and vertebrae can maintain blood flow during cardiac arrest; if combined with artificial respiration procedure, it can be life saving

4. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 4

5. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 5 Anatomy Heart chambers (Figure 12-2) Two upper chambers Two lower chambers Wall of each heart chamber is composed of cardiac muscle tissue called myocardium Endocardium—smooth lining of heart chambers— inflammation of endocardium called endocarditis Covering sac, or pericardium Pericardium is a two-layered fibrous sac with a lubricated space between the two layers Inner layer called Outer layer called

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7. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 7 Anatomy Heart action Contraction of the heart Relaxation is called Heart valves (Figure 12-3) Valves keep blood flowing through the heart and prevent backflow Consist of two atrioventricular, or AV, and two semilunar (SL) valves Tricuspid—at the opening of the right atrium into the ventricle Bicuspid (mitral)—at the opening of the left atrium into the ventricle Pulmonary semilunar—at the beginning of the pulmonary artery Aortic semilunar—at the beginning of the aorta

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9. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 9 Heart sounds Two distinct heart sounds in every heartbeat or cycle—“lub-dub” First sound (lub) -the vibration and closure of AV valves during contraction of the ventricles Second sound (dub) -the closure of the semilunar valves during relaxation of the ventricles

10. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 10 Blood flow through the heart (Figure 12-4) The heart acts as two separate pumps—the right atrium and ventricle performing different functions from the left atrium and ventricle Sequence of blood flow: venous blood enters the right atrium through the superior and inferior venae cavae o passes from the right atrium through the tricuspid valve to the right ventricle o from the right ventricle it passes through the pulmonary semilunar valve to the pulmonary artery to the lungs o blood moves from the lungs to the left atrium, passing through the bicuspid (mitral) valve to the left ventricle o blood in the left ventricle is pumped through the aortic semilunar valve into the aorta and is distributed to the body as a whole

11. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 11

12. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 12 Blood supply to the heart muscle coronary circulation myocardial infarction (heart attack) Angina pectoris Coronary bypass surgery

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14. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 14

15. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 15 Conduction system of the heart (Figure 12-7) Intercalated disks are electrical connectors SA (sinoatrial) node, the AV (atrioventricular) AV bundle (bundle of His Purkinje fibers

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17. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. HEART Slide 17 Electrocardiogram (Figure 12-8) Specialized conduction system structures generate and transmit the electrical impulses that result in contraction of the heart These tiny electrical impulses can be picked up on the surface of the body and transformed into visible tracings by a machine called an electrocardiograph The visible tracing of these electrical signals is called an electrocardiogram, or ECG The normal ECG has three deflections or waves P wave—associated with depolarization of the atria QRS complex—associated with depolarization of the ventricles T wave—associated with repolarization of the ventricles

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19. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. BLOOD VESSELS Slide 19 Types Arteries—carry blood away from the heart Veins—carry blood toward the heart Capillaries—carry blood from the arterioles to the venules

20. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. BLOOD VESSELS Slide 20 Structure (Figure 12-9) Arteries Tunica intima—inner layer of endothelial cells Tunica media—smooth muscle with some elastic tissue, thick in arteries; important in blood pressure regulation Tunica externa—thin layer of fibrous elastic connective tissue Capillaries—microscopic vessels with only one layer— tunica intima Veins Tunica intima—inner layer; valves prevent retrograde movement of blood Tunica media—smooth muscle; thin in veins Tunica externa—heavy layer of fibrous connective tissue in many veins