Unit 2A Human Form & Function

1. Unit 2AHuman Form & Function Body systems The heart & circulation

2. Exterior view of the heart Aorta Pulmonary artery Superior vena cava Left atrium Right atrium Pulmonary vein Right ventricle Left ventricle Inferior vena cava Image created by Patrick Lynch

3. Section through the heart Superior vena cava Aorta Pulmonary vein Pulmonary artery Left atrium Right atrium Bicuspid valve Semilunar valve Left ventricle Tricuspid valve Septum Inferior vena cava Right ventricle The Miles Kelly Art library, Wellcome Images

4. The chambers • The heart consists of four muscular chambers. • The two on the LHS are separated from the two on the right by the septum. • The upper chambers - the atria – receive blood. • The lower chambers - the ventricles – are the pumping chambers.

5. The chambers Left atrium Right atrium Septum Left ventricle Right ventricle The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

6. The blood vessels Superior vena cava Aorta Pulmonary artery Pulmonary vein Inferior vena cava The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

7. The blood vessels

8. The valves Pulmonic semilunar valve Aortic semilunar valve Tricuspid atrioventricular valve Bicuspid atrioventricular valve Chordae tendinae The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

9. The valves • The direction of the blood flow is controlled by four valves. • The atrioventricular valves are held in position by strong tendons, the chordae tendinae (tendineae). • The heart sounds – “lubb dubb” – result from the valves snapping shut.

10. From the upper body Blood circulation through the heart To the body To the lungs From the lungs From the lungs From the lower body The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

11. Heart beat The heart contains specialised conductive tissue which regulates the heartbeat. • The sinoatrial node (SA node or pacemaker) is a cluster of specialised cardiac cells in the wall of the right atrium which initiates the heartbeat. • The atrioventricular node (AV node) is the secondary pacemaker which regulates the beating of the ventricles.

12. Conductive tissue Sinoatrial (SA) node – the pacemaker Atrioventricular (AV) node Perkinje fibres The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

13. The circulatory system The blood vessels & circulation

14. The blood vessels • Arteries - muscular blood vessels that carry blood away from the heart. • Arterioles – small arteries that direct blood flow to various tissues.

15. Capillaries – microscopic blood vessels that connect arterioles and venules. They enable the exchange of substances between blood and surrounding tissues.

16. Venules – small veins. • Veins - blood vessels that carry blood toward the heart.

17. Arteries, veins and capillaries Vein Capillary bed Arteriole Venule Artery The Miles Kelly Art library, Wellcome Images

18. Blood vessels - structure Tunica interna (endothelium) Tunica externa Tunica media • Arteries & veins have three layers (the tunicae) – the tunica externa, tunica media & tunica interna The Miles Kelly Art library, Wellcome Images

19. Blood vessels - structure

20. Arteries and veins Notice the relatively thin wall and large lumen. VEIN Notice the relatively thick, muscular wall and small lumen. ARTERY G. Meyer – ANHB, UWA

21. Veins contain valves to prevent the back flow of blood Valve open Valve closed

22. Section through a vein showing a valve Valve The Miles Kelly Art library, Wellcome Images

23. Capillaries are where the exchange of materials takes place and consist of one layer of cells only The Miles Kelly Art library, Wellcome Images

24. A capillary bed Capillaries Artery Vein Jean Wade and Linda Sharp, Wellcome Images

25. Capillaries Capillary G. Meyer – ANHB, UWA L. Slomianka – ANHB, UWA

26. The circulatory system Medical Art Services, Munich, Wellcome Images

27. Double circulation Humans, like all mammals, have a double circulation: • The systemic circulationand • The pulmonary circulation.

28. The pulmonary circulation • The pulmonary circulationtakes deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium. • The right ventricle is the pump for the pulmonary circulation.

29. The systemic circulation • The systemic circulationtakes oxygenated blood from the left ventricle to all the tissues of the body and returns deoxygenated blood to the right atrium. • The left ventricle is the pump for the systemic circulation.

30. Double circulation LUNGS Pulmonary circulation HEART Systemic circulation OTHER PARTSOF THEBODY

31. Pulmonary circulation LUNGS Pulmonary vein Pulmonary artery Pulmonary circulation Left atrium HEART Right ventricle

32. Systemic circulation Right atrium Left ventricle HEART Vena cava Aorta Systemic circulation ALL PARTSOF THEBODY

33. Major arteries Carotid A Subclavian A Aorta HEART Celiac A Renal A Mesenteric A Common iliac A Femoral A The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

34. Major veins Jugular V Superior vena cava Subclavian V HEART Inferior vena cava Hepatic V Renal V Common iliac V The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

35. Study Guide Read: • TEXT BOOK • Chapter 6 Complete: • Activity 6.1 • RQ 1-12