Blood and Immunity

1. Blood and Immunity

2. The average person has about 5L blood-45% = blood cells -55% = fluid (plasma)

3. These parts can be separated by centrifuging

5. Components of the Blood 1) Plasma • 90% of plasma is water, but also contains blood proteins, glucose, vitamins, minerals, dissolved gases and waste products of digestion

6. plasma proteins help maintain homeostasis: -albumins : osmotic balance -globulins : produce antibodies for protection against invading microbes -fibrinogens: blood clotting

7. Erythrocytes: red blood cells • transports oxygen in hemoglobin • hemoglobin is an iron containing pigment

8. Anemia • Lack of iron in diet, or lack of processing of iron into hemoglobin • Can be treated with iron supplements

9. Each Hb molecule can carry four oxygen molecules – oxyhemoglobin or Hb(O2)4

10. RBCs have a biconcave shape = concave on both sides -increases surface area for gas exchange • RBCs have no nucleus = enucleated -enables the cell to carry more hemoglobin

11. Reproducing Red Blood Cells • bone marrow is the site of RBC reproduction = erythopoiesis • 5 million RBCs are produced every minute of the day

12. RBC's begin as stem cells and contain a nucleus : divide – shrink- nucleus disappears – discharge into blood • immature RBC's can undergo mitosis (have nucleus) • mature RBC's cannot undergo mitosis (no nucleus)

13. males = 5.5 million RBCs per milliliter of blood • females = 4.5 million/mL

14. Increased altitudes may effect number of red blood cells. How? • there is less oxygen available so the body compensates by creating more RBCs • a hormone called erythropoietin is produced by the kidneys and stimulates red blood cell production.

15. Blood Doping • Storing your own red blood cells for donation before sporting events • Increases oxygen carrying capacity • Also can use EPO (erythropoietin) as an injection • Difficult to catch

16. 3) Leukocytes: white blood cells • less numerous than RBCs • have a nucleus • some are phagocytes: engulf foreign cells, release an enzyme that digests the invader -remaining fragments are pus

17. some are lymphocytes-produce antibodies

18. 4) Platelets • initiate clotting • maintains homeostasis by preventing the loss of blood from torn or ruptured blood vessel • platelets break apart and release a protein called thromboplastin

19. thromboplastin + calcium ions activate prothrombin which is then converted into thrombin • thrombin then acts as an enzyme by splicing two AA's from a fibrinogen molecule • fibrinogen is converted into fibrin threads which seal the cut

22. Blood Groups • Karl Landsteiner -->different blood types exist • glycoproteinsare makers located on the membrane of some of the RBC's (A,B, or nothing) = antigen

24. The body produces antibodies for foreign antigens

25. antibodies attach to antigens and cause the blood to clump or agglutinate • agglutinated blood can no longer pass through the capillaries and clogs the tissues preventing oxygen and nutrient delivery

26. blood type AB is the universal acceptor (can accept all blood types) • blood type O is the universal donor (can be given to anyone but can only accept O)

28. Rhesus Factor • the rhesus factor is another antigen on the RBC • if you have the rhesus factor you are said to be Rh+ (85% of Canadians) • no antigen = Rh­

29. Rh- can donate blood to Rh+, but not reverse • there are no natural antibodies against the Rh factor, are produced after a transfusion

31. Erythroblastosisfetalis • Concern when mom is Rh- and baby is Rh+ • first pregnancy there is no problem • During birth, the blood of the child and mom mixes • now mom makes antibodies against Rh+

32. second pregnancy : if embryo is Rh+, the antibodies may diffuse across the placenta and destroy the embryo’s red blood cells

33. Treatments: • transfusions of Rh- blood 2. injections to inhibit the formation of antibodies against Rh+ antigens

34. Immune Response • The body's first line of defense is physical: skin, mucus, stomach acids, lysozymes • The second line of defense is utilized when invaders (antigens) take up residence within the body

35. leukocytes seek out and destroy the invader by phagocytosis • lymphocytes produce antibodies

36. Two Types of Lymphocytes • T cells • produced in the bone marrow, stored in the thymus gland • seeks out the intruder and signals the attack

37. 2. B cells: produce the chemical weapon: antibodies released from bone marrow Antibodies are "Y" shaped

38. they are specific and connect to a certain antigen “lock and key” • Antibodies that attach themselves to viruses alter their shape and prevent access to the entry ports of cells

39. Steps to an immune attack • Bacteria or virus –the antigen- enters the body 2. A macrophage engulfs the invader and pushes its antigen markers outside of the membrane

40. Helper T cells recognize the harmful markers and signal the B cells 4. B cells release antibodies which attach to the antigen

41. Killer T cells now recognize the foreign cell and kill it • The battle has been won so Suppressor T cells shut down the response 7. Memory T cells are made so the body can quickly identify the antigen should it return (immunity)

42. Immunity website

43. Allergies: body mistakes harmless cells for harmful invaders • Autoimmune disease: body attacks itself, ex rheumatoid arthritis

44. Vaccines • First vaccine developed by Edward Jenner in 1796 • reasoned that exposure to less harmful cowpox virus provided some immunity to the more violent smallpox virus

45. the first exposure to cowpox developed antibodies and because the two viruses are so similar, when smallpox was introduced T cells signalled B cells to produce antibodies

46. the rabies vaccine was developed by Louis Pasteur • he was able to grow the rabies virus in tissue cultures and inject the virus in milder form • Jonas Salk introduced the Polio vaccine in 1955

47. Summary: How do vaccines work? • a weakened microbe is injected into a person. The immune systems creates antibodies against that disease

49. Antibiotics • antibiotics are special chemical agents usually obtained from living organisms • in 1924 soil organisms were identified as the producers of a bacteria killing substance called actinomycetin

50. 1929 it was found that mold produced bacteria destroying secretion = penicillin