The Human Body's Cardiovascular System.ppt

Discussion on topic related to Cardiovascular system of the human body

1. The Cardiovascular System Delivers oxygen and nutrients to the body tissues and carries away wastes such as carbon dioxide via blood.

2. How Cardiovascular System works & what happens when the system failed to function?

3. The heart pumps blood throughout the body via blood vessels. If the cardiovascular system cannot perform its functions, wastes build up in tissues. Body organs fail to function properly, and then, once oxygen becomes depleted, they will die

4. Function its major function is transportation. The force to move the blood around the body is provided by the beating heart and blood pressure.

5. The Heart

6. The Heart Size, location, and orientation Approximately the size of a person’s fist, the hollow, cone-shaped heart weighs less than a pound. enclosed w/in the inferior mediastinum , the medial section of the thoracic cavity. apex – directed toward the left hip and rests on the diaphragm, approximately at the level of the fifth intercostal space. base – broad posterosuperior aspect, from w/c the great vessels of the body emerge.

7. The Heart Coverings pericardium – sac enclosure of the heart made up of three layers: 1. fibrous pericardium, 2. serous membrane (serous pericardium) and the parietal pericardium 3. visceral pericardium (epicardium) The epicardium is the innermost layer of pericardium and the outermost layer of the heart wall.

8. The Heart Walls The heart walls are composed of three layers: 1. epicardium 2. myocardium 3. endocardium Myocardium – consists of bundles of cardiac muscle ; the myocardium is reinforced internally by a network of dense fibrous connective tissue called skeleton of the heart. endocardium – sheet of endothelium that lines the heart chambers

9. Chambers and Associated Great Vessels the heart has four hollow cavities/chambers: two (2) atria; two (2) ventricles Which are lined by endocardium, w/c helps blood flow smoothly through the heart. The two superior atria are primarily receiving chambers fill the ventricles w/ blood and not responsible for pumping action of the heart. The two inferior ventricles are the discharging chamber pumps the heart R ventricle: forms most of heart’s ant. Surface L ventricle forms its apex

10. The heart

11. Interatrial septum – divides the atria longitudinally interventricular septum – divides the ventricles longitudinally The R side of the heart controls the pulmonary circulation The L side controls the systemic circulation

12. Pulmonary Circulation It receives oxygen-poor blood from the veins of the body through the large SVC & IVC and pumps it through the pulmonary trunk . The pulmonary trunk splits into the R & L pulmonary arteries , w/c carry blood to the lungs where O2 is picked up and CO2 is unloaded Pulmonary veins – where O2 rich blood drains from the lungs and is returned to the left side of the heart thru the four pulmonary veins.

13. Pulmonary Circulation

14. Systemic Circulation When O2 rich blood returned to the left atrium flows into the left ventricle and is pumped out into the aorta After O2 is delivered to tissues ,O2 blood circulates from the tissues back to the R atrium via the systemic veins, w/c finally empty their cargo into either SVC or IVC. It supplies O2 rich and nutrient rich blood to all body organs. L ventricle has thicker walls the R ventricle.

15. Pulmonary &Systemic Circulation

16. Heart Valves

17. The Heart Valves the heart is equipped w/ four valves: w/c allow blood to flow in only one direction thru the heart chambers Atrioventricular valves (AV valves)- prevents backflow into the atria when the ventricles contract. bicuspid valve (L AV valve) or sometimes called mitral valve consists of two flaps of endocardium tricuspid valve (R AV valve) has three flaps of endocardium they are both anchored by chordae tendineae (heart strings) into the walls of ventricles

18. Semilunar valves: Aortic semilunar valve & pulmonary semilunar valve guards the bases of the two large arteries leaving the ventricular chambers.

19. Coronary Circulation

20. Coronary Circulation blood supply of the heart Although the heart chambers are bathed w/ blood almost continuously, the blood contained in the heart does not nourish the myocardium. Coronary arteries – branch from the base of aorta and encircle the heart in the coronary sulcus Ant. Interventricular artery & circumflex artery on the left posterior interventricular artery and marginal artery on the R side. Coronary sinus – where cardiac veins empties deoxygenated blood

21. Coronary Circulation

22. What makes the heart beat?

23. Physiology of the Heart Heart pumps blood 1500 gallons in a single day. Although cardiac muscle can beat independently , the muscle cells in different areas of the heart have different rhythms. 60 times per minute-atrial cells 20-40 times per minute – ventricular cells ANS & intrinsic conduction system controls the rhythmic movement or pumping action of the heart.

24. Intrinsic Conduction System built into the heart tissue and sets its basic rhythm enforces a contraction rate of approximately 75 beats/min on the heart AV node – junction between atria and ventricles AV bundle(Bundle of His); R & L bundle branches located in the interventricular septum, and Purkinje Fibers, w/c spread w/in the myocardium of the ventricular walls. SA node – crescent-shaped node of tissue located in the R atrium often called the pacemaker

25. Intrinsic Conduction System

26. Cardiac Cycle & Heart Sounds Systole – contraction of ventricles; - relaxation of atria Diastole – relaxation of ventricles; - contraction of atria Cardiac Cycle - refers to the events of one complete heartbeat, during w/c both atria and ventricles contract and then relax. - 75 beats/min ( ave. pulse) - 0.8 sec

27. Five periods of cardiac cycle

28. Atrial diastole (ventricular filling) – Heart completely relax - Pressure in the heart is low ,AV valves are open, semilunar valve are closed - Blood is flowing passively thru the atria

29. Atrial Systole th e ventricles remain in diastole as the atria contract, forcing blood into ventricles to complete ventricular filling.

30. Isovolumetric contraction Atrial systole ends, and ventricular systole begins. The initial rise in intraventricular pressure closes the AV valves, preventing backflow of blood into the atria. ventricles are completely closed

31. Ventricular systole (ejection phase) The ventricles continue to contract, causing the intraventricular pressure to surpass the pressure in the major arteries leaving the heart. Semilunar valves are open; atria are again relaxed and filling w/ blood.

32. Isovolumetric relaxation ventricular diastole begins, the pressure in the ventricles falls below the major arteries, and the semilunar valves close to prevent backflow into the ventricles For another moment , the ventricles are completely closed chambers and IV pressure continues to decrease.

33. Cardiac Output (CO) Is the amount of blood pumped out by each side of the heart (actually each ventricle) in 1 min. The product of Heart Rate(HR) x Stroke Volume (SV) SV is the volume of blood pumped out by a ventricle w/ each heartbeat

34. Factors Modifying Basic Heart Rate Neural (ANS) control - during physical or emotional stress, the nerves of sympathetic division of the ANS more strongly stimulate the SA and AV nodes and the cardiac muscle.

35. Hormones and ions epinephrine and thyroxine– increases heart rate - electrolyte imbalances pose a real threat to the heart rate.

36. Physical Factors age, gender, exercise and body temperature influences heart rate.

37. Blood vessels

38. Microscopic Anatomy The walls of blood vessels have three layers (tunics) tunica intima (lines the lumen) tunica media (middle layer); mostly of smooth muscle and elastic fibers layer w/c constricts and dilates tunica externa (is the outermost layer); composed largely of fibrous connective tissue , and its function is to support and protect the vessels

39. Blood vessels

40. Skeletal pump and respiratory pump enhance venous return .

41. Arteries carry blood away from the heart carry O2 rich blood the walls are much thicker than those of the veins in order to expand as blood is forced into them and then recoil passively as the blood flows off into the circulation during diastole.

42. Veins Drain tissues and return the blood to the heart Carry O2 depleted , CO2 rich blood carry blood toward the heart and the pressure in them tends to be low all the time. Thus veins have thinner walls The lumens of the veins tend to be much larger than those of arteries, and they tend to have thinner tunica media but a thicker tunica externa Large veins have valves

43. Capillaries tiny hairlike capillaries, w/c extend and branch thru the tissues and connect the smallest arteries (arterioles) to the smallest veins ( venules ), directly serve the needs of the body cells. only one cell layer thick –just the tunica intima microcirculation – the flow of blood from an arteriole to a venule vascular shunt – a vessel that directly connects the arteriole and venule at opposite ends of the bed true capillaries , the actual exchange layer

44. Major arteries of the systemic circulation Aorta – is the largest artery of the body; about the size of the garden hose; it decreases slightly in diameter as it runs to its terminus. ascending aorta, arches to the left as the aortic arch , and then plunges downward thru the thorax, following the spine ( thoracic aorta) , finally to pass thru the diaphragm into the abdominopelvic cavity, where it becomes the abdominal aorta.

45. Arterial Branches of the Ascending Aorta R and left coronary artery w/c serve the heart

46. Arterial branches of the Aortic Arch Brachiocephalic trunk (first branch) R common carotid R internal & R external carotid R subclavian artery L common carotid (second branch) L internal (serves the brain) R external carotid artery (skin, and muscles of the head & neck)

47. L subclavian vertebral artery (serves part of the brain) axillary artery ( in the axilla) brachial artery ( supplies the arm) splits into radial & ulnar artery (serves the forearm)

48. Arterial Branches of the Thoracic Aorta intercostal arteries (10 pairs) supply the muscle of the thorax wall Bronchial arteries (supply lungs) esophageal arteries (supply esophagus) diaphragm (phrenic arteries)

49. Arterial Branches of the Abdominal Aorta celiac trunk – first branch of abdominal Aorta L gastric (supplies the stomach) splenic artery (spleen) common hepatic (supplies the liver) superior mesenteric – (supplies most of SI & the first half of LI Renal arteries – serves the kidneys gonadal arteries – serve the gonads ovarian arteries testicular arteries

50. Lumbar arteries – are several pairs of arteries serving the heavy muscles of the abdomen & trunk walls inf. Mesenteric artery – supplying the second half of the LI Common iliac (R & L) – final branches of the abdominal aorta internal iliac artery (supplies pelvic organs)

51. External artery (enters the thigh) becomes femoral artery; splits and becomes deep artery of the thigh and popliteal artery Popliteal artery splits and becomes ant. & post tibial artery ant. Tibial artery – dorsalis pedis – arcuate artery

52. Major Veins of the Systemic Circulation Superior Vena Cava – where veins of the head and arms drain de oxygenated blood Inferior Vena Cava – lower body

53. Veins draining in the SVC radial vein & ulnar vein – drain the forearm; unite to form the brachial vein, w/c empties into the axillary vein cephalic vein – provides for the superficial drainage of the lateral aspect of the arm and empties into the axillary vein basilic vein – superficial vein that drains the medial aspect of the arm and empties into the brachial vein proximally

54. medial cubital vein – joins the cephalic and basilic vein subclavian vein – receives venous blood from the arm thru axillary vein and from the skin & muscles of the head thru external jugular veins. vertebral vein – drains the post part of the brain internal jugular vein – drains the dural sinuses of the brain brachiocephalic (R & L) veins – are large veins that receive venous drainage from the subclavian, vertebral & internal jugular veins; drains into the SVC

55. Veins draining into the IVC The ant and post tibial vein and the fibular vein drain the leg. Post tibial vein – popliteal tibial vein – femoral vein – external iliac vein The great saphenous veins are the longest veins in the body. They receive the superficial drainage of the leg. They begin at the dorsal venous arch in the foot.

56.  Common iliac (R & L) vein – formed by the union of the external and the internal iliac vein; join to form the IVC in the abdominal cavity area.  R gonadal vein  - drains the R ovary in females and the R testicles in males.  L gonadal vein empties into the renal vein superiorly.  Renal veins – drain the kidney   Hepatic portal veins – drains the digestive tract organs and carries this blood thru the liver before it enters the systemic circulation  Hepatic (R & L) veins drain the liver

57. Arterial Supply of the brain (Circle of Willis) The brain is supplied by two pairs of arteries, the internal carotid arteries and the vertebral arteries internal carotid arteries branches of the common carotid arteries, run thru the neck and enter the skull thru the temporal. - ant. Cerebral artery - middle cerebral artery

58. Vertebral Arteries – pass upward from the subclavian arteries at the base of the neck join to form the basilar artery, this artery serves the brain stem and cerebellum as it travels upward. At the base of the cerebrum, the basilar divides to form the posterior cerebral arteries, w/c supply the posterior part of the brain.

59. The ant and posterior blood supplies of the brain are united by small communicating arterial branches.