1. The Transport System AKA The Cardiovascular System Or The Circulatory System

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4. The Structure of the Heart

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6. External Heart Anatomy

7. Internal Heart Anatomy

8. The Heart: Chambers  Right and left side act as separate pumps  Four chambers  Atria -  Receiving chambers  Right atrium  Left atrium  Ventricles  Pumping chambers  Right ventricle  Left ventricle

9. The Heart: Valves  Allow blood to flow in only one direction  Four valves  Atrioventricular valves – between atria and ventricles  Bicuspid valve (left)  Tricuspid valve (right)  Semilunar valves between ventricle and artery  Pulmonary semilunar valve  Aortic semilunar valve Valves open as blood is pumped through Held in place by chordae tendineae (“heart strings”) Close to prevent backflow

10. The Heart: Associated Great Vessels  Aorta  Leaves left ventricle  Pulmonary arteries  Leave right ventricle  Vena cava  Enters right atrium  Pulmonary veins (four)  Enter left atrium

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14. Blood Flow

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17. Two drops of blood are shown with a bright red oxygenated drop on the left and a deoxygenated drop on the right.

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20. Vessels © Kevin Petti, Ph.D. Departments of Natural Sciences Health, Exercise Science & Nutrition San Diego Miramar CollegeKevin Petti, Ph.D. Departments of Natural Sciences Health, Exercise Science & Nutrition San Diego Miramar College

21. Cardiac Vessels

22. Coronary Circulation  Blood in the heart chambers does not nourish the myocardium  The heart has its own nourishing circulatory system  Coronary arteries  Cardiac veins Heart AttackHeart Attack: A Block of one of these arteries that cause the muscle cells to die. One treatment is a bypass surgerybypass surgery

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24. The Cardiac Cycle – “Heartbeat”

25. The Heart: Cardiac Cycle The Heart: Cardiac Cycle  Atria contract simultaneously  Atria relax, then ventricles contract  Systole = contraction; aortic valve is OPEN  Diastole = relaxation; aortic valve is CLOSED  Cardiac cycle – events of one complete heart beat

26. The Heart: Cardiac Cycle The Heart: Cardiac Cycle Diastole The heart muscle is relaxed this is called diastole. There is no pressure in the heart chambers. Blood tries to flow back into the heart but closes the semi- lunar valves.

27. The Heart: Cardiac Cycle The Heart: Cardiac Cycle Diastole Both atria fill with blood returning to the heart in the veins. The right atrium fills with blood returning in the vena cava from the body tissues (deoxygenated). The left atrium fills with blood returning from the lungs (oxygenated). The atrio-ventricular valves are still closed and the atria fill up.

28. The Heart: Cardiac Cycle The Heart: Cardiac Cycle Late Diastole In this diagram the heart is still relaxed (diastole). The pressure of blood returning to the heart and filling the atria is now high enough to open the atrio- ventricular valves. The pressure in the atria is greater than the pressure in the ventricles. Atrio-ventricular valves open. Ventricles begin to fill with blood.

29. The Heart: Cardiac Cycle The Heart: Cardiac Cycle Atrial systole Both atria contract together (see control of heart rate) The muscles of the atria contract. Volume of the atria reduces. Pressure of blood increases. Blood flows into the ventricles, filling these chambers and causing the ventricle walls to stretch.

30. The Heart: Cardiac Cycle The Heart: Cardiac Cycle Ventricular Systole The ventricle contracts (systole) The pressure increases in the ventricle The atrio-ventricular valve closes The pressure rises further Pressure in the ventricle is greater than the artery, semi-lunar valve opens Blood pulses into the arteries

31. The Heart: Cardiac Cycle The Heart: Cardiac Cycle

32. Blood Pressure

33. Blood Pressure Blood Pressure Measurements by health professionals are made on the pressure in large arteries  Systolic – pressure at the peak of ventricular contraction  Diastolic – pressure when ventricles relax  Pressure in blood vessels decreases as the distance away from the heart increases

34. Measuring Arterial Blood Pressure

35. Variations in Blood Pressure  Human normal range is variable  Normal  140–110 mm Hg systolic  80–75 mm Hg diastolic  Hypotension  Low systolic (below 110 mm HG)  Often associated with illness  Hypertension  High systolic (above 140 mm HG)  Can be dangerous if it is chronic

36. Control of the Heartbeat

37. Regulation of the Heartbeat Regulation of the Heartbeat  The contractions of the cardiac muscles are myogenic (they originate within the heart muscle).  The nerve impulses do NOT originate in the brain, but from within a region of the right atrium called the Sino-Atrial Node (SA node).  SA node is also called the pacemaker.  This causes the muscle cells to contract at regular intervals.

38. Regulation of the Heartbeat The impulse from the SA node speads to the Atrio-Ventricular node (AV node). It spreads down to the apex. Then it spreads upward, causing the ventricles to contract and push blood up into the arteries.

39. Regulation of the Heartbeat The heart is mostly autonomous. The brain does influence the frequency of the heartbeats. Impulses from the lower part of the brain stem (medulla) can either increase or decrease the heartbeat.

40. Regulation of the Heartbeat Hormones also affect heart rate. Adrenaline (epinephrine) from the adrenal glands increases heart rate. “Fight or Flight response”

41. Regulation of the Heartbeat If the SA node does not work properly, it is possible to implant an artificial pacemaker.

42. Blood Vessels: The Vascular System  Taking blood to the tissues and back  Arteries  Capillaries  Veins

43. Blood Vessels: Arteries  they take blood AWAY from the heart at high speeds (10-40 cm/sec).  They have muscular walls, but no valves.  A collagen layer resists expansion  Muscle contracts to maintain high pressure all the way to the tissues.

44. Arteries VAn 308-Functional Anatomy

45. Blood Vessels: Veins  they take blood TO the heart at moderate speeds (5-20 cm/sec).  They have the largest lumen.  They have valves to prevent backflow.  They operate under low pressure to reduce resistance to blood flow.

46. Veins © Kevin Petti, Ph.D. Departments of Natural Sciences Health, Exercise Science & Nutrition San Diego Miramar CollegeKevin Petti, Ph.D. Departments of Natural Sciences Health, Exercise Science & Nutrition San Diego Miramar College

47. Blood Vessels: Capillaries  they are the location where blood can exchange material with tissues. They are only one cell thick  They move blood very slowly (<0.1 cm/sec)

48. The Vascular System

49. Major Arteries of Systemic Circulation

50. Major Veins of Systemic Circulation

51. Capillary Beds  True capillaries – exchange vessels  Oxygen and nutrients cross to cells  Carbon dioxide and metabolic waste products cross into blood

52. Blood Circulation

53. Blood

54. Blood  The only fluid tissue in the human body  By weight, it’s about 8% of the human body.  Living cells 45-50%  Non-living plasma50-55%

57. Type of Blood Cells

58. Blood Plasma  Composed of approximately 90 percent water  Includes many dissolved substances  Nutrients  Salts (metal ions)  Respiratory gases  Hormones  Proteins  Waste products

59. Cells  Erythrocytes = red blood cells  Leukocytes = white blood cells  Thrombocytes = platelets

60. Erythrocytes (Red Blood Cells)  The main function is to carry oxygen  Anatomy of circulating erythrocytes  concave disks  Essentially bags of hemoglobin  Have no nucleus  Contain very few organelles  Make up 90% of blood cells

61. Hemoglobin  Iron-containing protein  Binds strongly, but reversibly, to oxygen  Each hemoglobin molecule has four oxygen binding sites  Each erythrocyte has 250 million hemoglobin molecules

62. Two drops of blood are shown with a bright red oxygenated drop on the left and a deoxygenated drop on the right.

64. Fate of Erythrocytes Slide 10.15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Unable to divide, grow, or synthesize proteins  Wear out in 100 to 120 days  When worn out, are eliminated by phagocytes in the spleen or liver  New erythrocytes are made in the bone marrow

65. Leukocytes (White Blood Cells)  Crucial in the body’s defense against disease  These are complete cells, with a nucleus and organelles  They only live 3-4 days.

66. Types of Leukocytes Slide 10.10a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Phagocytes – a non- specific type of white blood cell that protects the body by ingesting harmful or dead material.  They help fight infection.  In large numbers, they look like pus. Figure 10.4

67. Types of Leukocytes Slide 10.10a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lymphocytes – a specific type of white blood cell that produces antibodies to fight specific antigens. Figure 10.4

68. Platelets  Fragments with no nuclei  Last 5-9 days  Needed for the clotting process Needed for the clotting process

70. Blood Clotting Slide 10.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Blood usually clots within 3 to 6 minutes  The clot remains as endothelium regenerates  The clot is broken down after tissue repair

71. Undesirable Clotting Slide 10.23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Thrombus  A clot in an unbroken blood vessel  Can be deadly in areas like the heart  Embolus  A thrombus that breaks away and floats freely in the bloodstream  Can later clog vessels in critical areas such as the brain

72. Bleeding Disorders Slide 10.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Thrombocytopenia  Platelet deficiency  Even normal movements can cause bleeding from small blood vessels that require platelets for clotting  Hemophilia  Hereditary bleeding disorder  Normal clotting factors are missing

73. Closure Name one thing you learned about the transport system. What’s one thing you’re still confused about. What’s something you would like more information about.