Chapter 11: The Cardiovascular System

1. Chapter 11:The Cardiovascular System Part A

2. The Cardiovascular System • A closed system of the heart and blood vessels • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

3. The Heart • Location • Thorax between the lungs • In the inferior mediastinum • Orientation • Pointed apex directed toward left hip • At 5th rib • Base points toward right shoulder • Posteriosuperior = base (top) • At 2nd rib • Size • About the size of your fist

4. The Heart: Coverings • Pericardium – a double serous membrane • Visceral pericardium • Next to heart • Parietal pericardium • Outside layer • Anchors heart to diaphragm & sternum • Serous fluid fills the space between the layers of pericardium • Decreases friction

5. The Heart

6. The Heart

7. The Heart

8. The Heart: Coverings • Pericardium—a double-walled sac • Fibrous pericardium is loose and superficial • Serous membrane is deep to the fibrous pericardium and composed of two layers: • Visceral pericardium • Next to heart; also known as the epicardium • Parietal pericardium • Outside layer that lines the inner surface of the fibrous pericardium • Serous fluid fills the space between the layers of pericardium

9. The Heart: Heart Wall

10. The Heart: Heart Wall • Three layers: • Epicardium • Outside layer • This layer is the parietal pericardium • Connective tissue layer • Myocardium • Middle layer • Mostly cardiac muscle - twisted • Endocardium • Inner layer • Endothelium – continues into vessels

11. The Heart: Heart Wall

12. The Heart: Chambers • Right and left side act as separate pumps • Four chambers • Atria • Receiving chambers • Right atrium • Left atrium • Ventricles = pumps • Discharging chambers • Right ventricle • Left ventricle Figure 11.2c

13. The Heart: Chambers

14. Differences in Right and Left Ventricles

15. The Heart: Septa • Interventricular septum • Separates the two ventricles • Interatrial septum • Separates the two atria

17. The Heart • Double pump • Right – pulmonary • Oxygen-poor blood through superior & inferior vena cava & out pulmonary trunk (right & left arteries)  lungs • Left – systemic • Left ventricle is more muscular

18. Brain Break!!

19. Blood Circulation Figure 11.3

20. The Heart: Valves • Allow blood to flow in only one direction to prevent backflow • Types of valves: • Atrioventricular(AV) valves – between atria and ventricles • Mitral (Bicuspid) valve –left side of heart– 2 flaps • Tricuspid valve (right side of heart) – (3 flaps) • Semilunar valves -between ventricle and artery • Pulmonarysemilunar valve – between right ventricle & pulmonary arteries (3 flaps) • Aorticsemilunar valve – between left ventricle & aorta (3 flaps)

22. Heart Valve—Normal Operation • Valves stop backflow of blood • AV valves: • Open – heart relaxation • Closed – ventricles contract • SL valves: • Closed – heart relaxation • Open – ventricles contract • Notice these valves operateoppositeof one another to force a one-way path of blood through the heart Video Clip: Heart Valves

23. Operation of the AV valves Blood returning tothe atria, putspressure againstAV valves; the AVvalves are forcedopen As the ventriclesfill, AV valve flapshang limply intoventricles AV valves open Ventricles Atria contract,forcing additionalblood into ventricles (a) AV Valves: Tricuspid Valve & Mitral Valve Figure 11.5a, step 3

24. Ventricles contract,forcing bloodagainst AV valveflaps AV valves close Chordae tendineaetighten, preventingvalve flaps fromeverting into atria AV valves closed (a) AV Valves: Tricuspid Valve & Mitral Valve Figure 11.5a, step 6

25. Operation of the Semilunar Valves As ventriclesrelax, andintraventricularpressure falls,blood flowsback fromarteries, fillingthe leaflets of semilunarvalves andforcing themto close As ventriclescontract andintraventricularpressure rises,blood is pushedup againstsemilunarvalves, forcingthem open Aorta Pulmonarytrunk (b) Semilunar valveopen Semilunar valveclosed Semilunar Valves: Pulmonary Valve & Aortic Valve

26. The Heart: Valves • Valves open as blood is pumped through • Held in place by chordae tendineae (“heart strings”) • Close to prevent backflow • Stenosis – bad or stiff valves; can be replaced Video Clip: Heart Valve Replacement

27. Systemic and Pulmonary Circulations • Systemic Circulation • Blood flows from the left side of the heart through the body tissues and back to the right side of the heart • Pulmonary Circulation • Blood flows from the right side of the heart to the lungs and back to the left side of the heart

28. Mini-Quiz!! • 1. Name the serous membrane that lies directly on the heart: • A. visceral pericardium • B. parietal pericardium • C. epicardium • D. Both a & c

29. 2. The receiving chambers of the heart are _________ chambers and are called _________. • A. lower, atria • B. upper, atria • C. lower, ventricles • D. upper, ventricles

30. 3. The right side of the heart is the _____________ side, and the left the ______________ side. • A. pulmonary; systemic • B. systemic; pulmonary • C. oxygen-rich; oxygen-poor • D. more muscular; less muscular

31. 4. The valve between the right atrium and ventricle is the _____________ valve, while the valve between the left atrium and ventricle is the ____________ valve. • A. pulmonary semilunar; aortic semilunar • B. aortic semilunar; pulmonary semilunar • C. tricuspid; bicuspid (mitral) • D. bicuspid (mitral); tricuspid

32. 5. Blood flows from the left side of the heart through the body tissues and back to the right side of the heart. This describes: • A. systemic circulation • B. pulmonary circulation