THE BODY

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CHAPTER 43 THE BODYS DEFENSES
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• Nonspecific mechanisms and general barriers
• Skin-water proof and impenetrable if unbroken
  acidity of sweat and normal bacteria flora
  inhibit pathogens
• Lysozymes in perspiration, tears and saliva
  attacks cell walls of many bacteria
• Stomach acid kill most bacteria in food

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Hair and cilia in respiratory tracts traps
bacteria and viruses
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Neutrophils-most numerous, attracted by chemical
signals, become amoeboid, phagocytic, living only
a few days Monocytes-macrophages-larger, longer
lived, wander through interstitial fluid, found
in connective tissue, lymph nodes, and spleen,
interact with T-cells

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• Eosinophils-enzymes against parasitic worms
• Natural killer cells-lyse infected or abnormal
  cells, similar to cytotoxic Ts but less
  discriminatory
• Basophils (circulating)-and mast cells (in
  connective tissue) degranulate releasing
  histamines that cause vasodilation of local
  capillaries and makes them leakier
• Dendritic cells-are a type of blood cell that
  have the ability to stimulate an immune response
  against specific targets and are being widely
  pursued as a new treatment for cancer and viral
  diseases. Phagocytic, and interact with T B
  cells

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Cytotoxic T cells killing a cancerous cell
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Inflammatory Response

• Injured tissue releases prostaglandins and
  histamines that causes basophils and mast cells
  to release more histamines causing
• Vasodilation of capillaries and increased blood
  flow
• Capillaries to become leakier
• Increased metabolic rate and local temperature
  rises
• Neutrophils become amoeboid and leave capillaries
  and begin to phagocytize
• Monocytes become macrophages and move into the
  area and begin phagocytizing then become antigen
  presenting cells and release interleukin 1 to
  attract T cells
• -- Dendritic cells phagocytize and present
  antigens to
• T B cells

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Inflammatory Response

• Toxins and pyrogens cause fever
• Various chemicals released cause pluripotent stem
  cells to divide more rapidly
• Natural killers in area check locals cells MHC
  Is for antigens
• Viral infected cells release interferon
• Complements stick to pathogens and lyse or induce
  opsonization
• T lymphocytes and B lymphocytes are alerted and
  move into the area

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Phagocytosis by a macrophage
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Clonal Selection-the antibodies of each B cell
only recognize certain antibodies but
collectively they should recognize any antigen
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B lymphocyte
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T cell infected with HIV
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Close-up of T cell infected with HIV
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Arthritis
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• Rh factor
• When an Rh fetus is carried by an Rh- mother,
  during birth or the last few days before birth,
  some Rh blood can go into the mothers body and
  she will make antibodies against it. That child
  will not have a problem because it is born before
  the antibodies are produced. However any
  subsequent Rh fetus will get antibodies form the
  mother that will attack its blood resulting in
  hemolytic anemia and death.
• To prevent this problem, Rh- mothers are given an
  injection of Rhogan that contains small amounts
  of Rh antibodies two or three times during their
  pregnancies.