Anatomy of the Cardiovascular System

1. Anatomy of the Cardiovascular System

2. Cardiovascular System • Also circulatory system • Consists of: the heart, arteries, veins, capillaries

3. Heart • Four chamber muscular organ • Comparable to the size of a closed fist • Located in the mediastinum

4. Heart

5. Coverings of the Heart • Pericardium – loose fitting sac surrounding the heart • Fibrous pericardium – tough, loose-fitting, inelastic • Serous pericardium • Parietal layer: lines the inside of the fibrous pericardium • Visceral layer: adheres to outside of the heart • Pericardial space: between parietal and visceral layer • Filled with 10-15mL of pericardial fluid • Decreases friction

6. Walls of the Heart • Epicardium – outer layer • Epicardium = serous pericardium • Myocardium – thick, contractile layer composed of cardiac muscle cells • Endocaridium – interior of cardiac wall

7. Walls of the Heart

8. Chambers of the Heart • Atria – two superior chambers • “Receiving chambers” • Blood from veins enters atria • Ventricles – two inferior chambers • “pumping chambers” • Separated by interventricular septum

9. Valves of the Heart • Permit blood flow in one direction during circulation • Atrioventricular valves (AV valves) • Also cuspid valves • Between atria and ventricles • Semilunar (SL valves) • Between ventricles and vessles

10. Chambers & Valves Trace the blood flow through the heart

11. Blood Supply to the Heart • After traveling through the capillaries of the heart, blood empties into the R atrium via the coronary sinus

12. Conduction System of the Heart • Four structures composed of modified cardiac muscle • Sinoatrial Node (SA Node) • Pacemaker of the heart • 100s of cells in the R atrium near the opening of the superior vena cava • Atrioventricular Node (AV Node) • Left lower border of R atrium

13. Conduction System of the Heart • Atrioventricular Bundle • Also Bundle of His • Bundle of specialized cardiac muscle fibers originating in the AV node • Branches into R and L branches eventually becoming Purkinje fibers • Extend into the walls of the ventricles and papillary muscles

14. Types of Blood Vessels • Artery – carries oxygenated blood away from the heart • Arteriole: small artery • Precapillary sphincters: regulate the blood flow into capillaries

15. Types of Blood Vessels • Vein – carries unoxygenated blood towards the heart • Great ability to stretch (capacitance) • Function as reservoirs: blood pools in the valves then is pushed forward from the pumping pressure • Venules: small vein

16. Types of Blood Vessels

17. Types of Blood Vessels • Capillaries – arterial system switches to venous system • “primary exchange vessels” • Transport materials to and from the cells • Speed of blood flow decreases to increase contact time

18. Types of Blood Vessels

19. Structure of Blood Vessels • Tunica adventitia - outermost layer • Fibrous connective tissue • Holds vessels open; prevents tearing of vessels walls during body movements • Larger in veins than arteries • Tunica media – middle layer • Smooth muscle and elastic CT • Helps vessels constrict and dilate • Larger in arteries

20. Structure of Blood Vessels • Tunica intima – innermost layer • Composed of endothelium • Semilunar valves present in veins • One cell thick in capillaries

21. Circulatory Routes • Systemic Circulation – blood flow from the L ventricle to the body & back to the R atrium • Pulmonary Circulation – blood flow from the R ventricle to the lungs and back to the L atrium

22. Circulatory Routes

23. Aorta

24. Arch of aorta Subclavian (L and R) Brachiocephalic common carotid (L and R) Axillary (L and R) Brachial (L and R) Radial Ulnar Abdominal aorta Common iliac External iliac Femoral Popliteal Posterior tibial Anterior tibial Dorsal pedis Systemic Arteries

26. Superior vena cava Inferior vena cava External jugular Internal jugular Brachiocephalic (L and R) Subclavian (L and R) Cephalic axillary Basilic Median basilic Median cubital Common iliac External iliac Femoral Popliteal Great saphenous Small saphenous Systemic Veins

28. Pericardium Disorders • Pericarditis – inflammation of the heart • Causes: trauma, viral or bacteria infection, tumor • Edema causes visceral and parietal layers to rub together = chest pain • Pus or blood build up in pericardial space • S/S • Pain with respirations or coughing, dyspnea, restlessness • Complications: Pericardial Effusion, Cardiac Tamponade • Treatment: • Antibiotics, pain meds, antiinflammatory meds, pericardiocentesis (Cardiac Tamponade)

29. Cardiac Tamponade

30. Heart Valve Disorders • General Principles: • Congenital defect: decreased pumping efficiency • Incompetent valve leak: allows backflow into previous chamber • Stenosed valves: narrowed valve; slowing blood from out of chamber

31. Heart Valve Disorders • Mitral Valve Prolapse (MVP) • Flaps of mitral valve extend back into L atrium causes leaking • Mostly genetic basis • 1 in 20 people • S/S: most asymptomatic; chest pain, fatigue • Treatment: valvuloplasty

32. Mitral Valve Prolapse

33. Heart Valve Disorders • Aortic Regurgitation • Blood leaks back into L ventricle during ejection into the aorta • Volume overload in L ventricle, hypertrophy, dilation of L ventricle • Complications: myocaridal ischemia • Treatment: valvuloplasty

34. Myocardium Disorders • Atherosclerosis • Type of arteriosclerosis • Lipids build up on the inside of vessel walls  calcify  vessels hard & brittle • Risk factors: cigarette smoking, high fat/cholesterol diet, hypertension

35. Atherosclerosis

36. Myocardium Disorders • Myocardial Infarction • “Heart Attack” • Coronary thrombosis: clot • Coronary embolism: mobilized clot • Occlude coronary artery  heart tissue deprived of oxygen  cell death • S/S: • Angina pectoris – severe chest pain resulting from inadequate oxygen to myocardium • Treatment: Coronary Bypass Surgery • Veins are harvested from other areas of the body and used to bypass obstructions

38. Myocardium Disorders • Congestive Heart Failure (CHF) • “Left-sided Heart Failure” • Inability of the L ventricle to pump blood efficiently • Causes: myocardial infarction • S/S: decreased pumping pressure in systemic circulation; retained fluids • Can lead to congestion in pulmonary circulation  pulmonary edema  right-sided heart failure • Treatment: heart transplant

39. Congestive Heart Failure

40. Myocardium Disorders • Coronary Artery Disease (CAD) • Leading cause of death in US • General term to describe decreased blood flow to myocardium & associated side effects

41. Disorders of the Arteries • Arteriosclerosis • Arteries become occluded, weak and hardened • Complications: ischemia, necrosis, gangrene • Risk factors: age, diabetes, high fat/cholesterol diet, hypertension, smoking • Treatment: vasodilators, angioplasty, stent placement, bypass surgery • Complications: aneurysm

42. Angioplasty

43. Disorders of Veins • Varicose Veins • Enlarged veins caused by pooling • Results in varicosities or varices (“spider veins”) • Risk factors: standing for long periods • Semilunar valves widen  more pooling • Treatment: compression stockings, surgical removal

44. Varicose Veins

45. Disorders of Veins • Phlebitis – vein inflammation • Causes: irritation by IV catheter • Thrombophlebitis • Deep vein thrombosis (DVT) • Phlebitis caused by a clot • S/S • Pain, redness, swelling • Complications • Pulmonary embolism

46. DVT

47. Pulmonary Embolism

48. Venous Stasis Ulcers • Result of chronic vein insufficiency • Lack of oxygen to peripheral tissues • Elevate leg & apply pressure • Irregular edges • “Aching” pain