1. Circulatory System

2. Functions of the Circulatory System:
1. Transports nutrients from intestines to all cells of the body
some cells require more nutrients than others
(ex. brain cells,
liver cells,
active muscle cells)

3. 2. Transports nitrogenous wastes from cells of the body to the kidneys
your cells produce nitrogenous wastes when they break down proteins

4. 3. Transports oxygen from your lungs to cells of the body
cells need O2 to produce ATP (energy)
This process is called aerobic respiration

5. 4. Transport carbon dioxide from your cells to the lungs to be exhaled
CO2 is a by product of aerobic respiration

6. 5. Transports hormones from the endocrine gland that produce them to their target cells
insulin is produced in your pancreas
it is transported in your bloodstream to cells in muscles and liver

7. 6. Distributes heat throughout the body
if you are too hot, blood is brought to your skin so the heat can be removed as sweat evaporates

8. if you are too cold, blood flow to the skin is restricted, allowing you to conserve heat in the body

9. Components of the circulatory system
A. Blood vessels – function to transport blood throughout the body

10. 5 major types of blood vessels
1. Arteries – vessels that transport blood away from the heart
they usually carry oxygenated blood

11. 2. Arterioles – small arteries
important because the smooth muscle in their walls can constrict and relax
constricting arterioles to one area of the body reduces blood flow to that area

12. example – when you are cold, you constrict the arterioles that send blood to your skin

13. 3. Capillaries – the smallest of all blood vessels (some are slightly larger than a single red blood cell)
capillaries are important because their walls are thin enough to allow the exchange of materials (O2, CO2, wastes, nutrients, and hormones)

14. you have several thousand miles of capillaries

15. 4. Veins – vessels that return blood to the heart
they usually carry deoxygenated blood
the largest veins in the body are the inferior and superior vena cavae (~ 1.2 inches in diameter)

16. the vena cavae empty blood returning from the body into the heart
veins differ in structure from arteries in that veins:

17. are often larger in diameter
have thinner walls because blood pressure in the veins is much less than that in the arteries
have one-way valves that prevent the back flow of blood (keeps blood moving toward the heart)

18. 5. Venules – (= “little vein”) – tiny vessels that transport blood from the capillaries to the veins
heart 
arteries 
arterioles 
capillaries 
venules 
veins 
back to the heart

19. Blood pressure varies as it flows through each type of vessel
blood pressure is highest in the artery leaving the heart (aorta)

20. blood leaving the heart must be pumped under great pressure so that it can travel through the body

21. blood pressure falls steadily as it moves through the circulatory system
It is lowest in the veins emptying into the heart (vena cavae)

22. B. Lymphatic vessels – function to collect fluid that leaks from the capillaries and return it to the circulatory system

23. about 3 liters of fluid leak from your capillaries each day
this could be harmful to your health because you have only 5 – 6 liters of blood

24. capillaries leak because they are so thin (only 1 cell layer thick)

25. every time your heart beats, fluid is forced out of the capillaries and into the surrounding tissues
this fluid enters lymphatic capillaries where it is now called lymph

26. lymph flows into larger and larger lymphatic vessels, in a 1-way direction toward the heart

27. lymph is cleaned by tiny structures called lymph nodes as it makes its way toward the heart

28. some lymph nodes are scattered along lymphatic vessels, while others are concentrated in specific areas (armpit, neck)

29. If you have an infection in your hand, lymph nodes in the armpit on that side of the body become painfully swollen (filled with dead bacteria that have been filtered out of lymph returning from the hand)

30. clean lymph is dumped into 2 large veins that enter the heart – returning this fluid to the circulatory system

31. C. Blood – is made up of liquid (plasma) and 3 kinds of solids
1. Plasma makes up 55% of the total blood volume

32. Plasma contains:
a large amount of water
metabolites (ex. glucose, vitamins, and hormones)
nitrogenous wastes (ex. urea)
salts and ions (ex. sodium ions, chloride ions, and bicarbonate ions)

33. proteins

34. 2. Solids make up 45% of the total blood volume
The 3 major solids found in blood are red blood cells, white blood cells, and platelets

35. Red blood cells (erythrocytes) are flattened disks that function to transport oxygen

36. they are able to transport oxygen because they are packed with hemoglobin – a protein that binds to O2 in the lungs and releases it to the cells in the body

37. RBCs differ from all other cells in the body in what they lose their nucleus when they start transporting O2
since they do not have a nucleus, they cannot reproduce themselves and die after about 4 months – they must continually be produced

38. RBCs are produced in red bone marrow

39. If more RBCs die than are produced, you suffer from a condition called anemia
individuals with anemia feel tired all the time because their cells are not getting enough O2

40. White blood cells (leukocytes) are larger than RBCs and contain a nucleus

41. they function to defend your body against disease by attacking and destroying bacteria, viruses, and cancer cells
like RBCs, WBCs are produced in red bone marrow

42. sometimes cancer occurs among pre-WBCs in the bone marrow – called leukemia

43. Platelets are fragments that function in blood clotting

44. platelets circulating in your blood vessels are inactive – activated when blood vessel is damaged
once activated they release a clotting protein that triggers a series of reactions involving about 14 other clotting proteins

45. If all clotting factors are present in the blood, a fibrin net will be formed
this net traps other platelets, RBCs and WBCs, forming a clot
this clot plugs the damaged blood vessel, stopping bleeding

47. If you are missing only 1 of the clotting factors your blood will not clot and you will be suffering from a condition called hemophilia (free-bleeders disease)

48. Blood Typing:
The surface of each RBC in you body displays about 100 different antigens
the most important antigens on the surface of your RBCs are: A, B, and Rh

49. the presence of the A and B antigens determine your ABO blood grouping, while the presence of the Rh antigen determines whether you are positive or negative

50. 1. ABO blood groupings in humans:
AB, or O
individuals whose RBCs are covered with A antigens (but no B antigens) have type A blood
If you have type A blood, you have B antibodies (anti-B) floating in your plasma

51. individuals whose RBCs are covered with B antigens (but no A antigens) have type B blood
If you have type B blood, you have A antibodies (anti-A) floating in your plasma

52. individuals whose RBCs are covered with both A and B antigens have type AB blood
If you have type AB blood, you have neither A or B antibodies in your plasma

54. Knowing a person’s ABO blood type is very important in performing a blood transfusion
If you are given an incompatible blood type, you will have a severe reaction in which the antibodies in your plasma attack the antigens on the surface of the RBCs entering your bloodstream, causing the RBCs to agglutinate (clump) and rupture

55. this type of reaction in called hemolysis
the ruptured RBCs release hemoglobin, which may cause kidney damage

56. 2. Rh system
this system is so named because it was first worked out in the blood of the Rhesus monkey
like the ABO grouping, the Rh system is based on antigens on the surface of your RBCs

57. people whose RBCs have Rh antigens are Rh positive
people whose RBCs do not have Rh antigens are Rh negative

58. There are 8 possible blood types with the ABO and Rh antigens:

59. The most common problem with Rh incompatibility may arise during pregnancy

60. normally, there is no mixing of the mother’s and baby’s blood during pregnancy

61. however, during the birthing process, some of the baby’s blood mixes with it’s mother’s blood – if the mother is Rh- and her child is Rh+ she will begin producing Rh antibodies

63. fortunately this does not have an effect on the present pregnancy – however, if the mother were to ever become pregnant with another Rh+ baby, her Rh antibodies (produced at the end of the 1st pregnancy) would pass through the placenta and destroy the baby’s RBCs

65. Rh incompatibility is not much of a problem presently because if an Rh- woman ever gives birth to an Rh+ child, she is immediately given a shot of Rho-GAM, which stops her body from producing Rh antibodies

66. she must receive a shot of Rho-GAM every time she becomes pregnant with an Rh+ baby

67. Blood Groups in the U.S. O A B AB Rh+ Whites Blacks Hawaiians 45% 41%
10% 4%
85%
Blacks
48%
27%
21% 4%
88%
Hawaiians
37%
61%
1.5%
0.5%
100%

68. Blood Types in Southeast U.S.
A+ = 1 out of 3
A- = 1 out of 16
O+ = 1 out of 3
O- = 1 out of 15
B+ = 1 out of 12
B- = 1 out of 67
AB+ = 1 out of 29
AB- = 1 out of 167

69. Disorders of the Blood
1. Anemia – RBC production slows down (many different types)

70. 2. Sickle cell anemia – inherited condition in which abnormal hemoglobin is produced, causing their RBCs to become deformed

71. these deformed cells cannot move through blood vessels as easily as normal RBCs
these blood clots may cut off the blood supply to an organ

72. 3. Mononucleosis – a contagious disease caused by a virus that infects the white blood cells

73. symptoms include fatigue, headache, dizziness, sore throat, and fever
there is no cure, but with rest, the individual usually suffers no permanent ill effects

74. 4. Leukemia – cancer of the WBCs
normal
leukemia

75. 5. Hemorrhage – bleeding, either internal or external