HUMAN BODY SYSTEMS

IMMUNE SYSTEM CHAPTER 40

Why do some of us have allergic reactions? Consider allergies to tree pollen.

Allergies and Our Immune System Response Allergies result from immune responses within the body. Common particles identified as pathogens  produce defense reactions.

MAST CELLS Produce histamine dilates small blood vessels as part of the inflammatory response reaction to injury or infection. Produce heparin a natural anticoagulant Prevents inappropriate blood clotting in vessels allergies-and-dust-mites-video.htmhttp://health.howstuffworks.com/human-body/14063-body-invaders- allergies-and-dust-mites-video.htm

Germ Theory of Disease A disease is any change other than an injury that disrupts the normal functions of the body. Germ Theory – conclusion that infectious diseases were caused by different types of microorganisms. Based upon the work of Louis Pasteur and Robert Koch

Koch’s Postulates Rules developed to identify the microorganism that causes a specific disease. 1. Pathogen should always be found in body of a sick organism not a healthy one 2. Pathogen must be isolated and grown in pure culture in lab 3. Cultured pathogens should cause same disease when placed in new host 4. Injected pathogen isolated from second host should be identical to original

Nonspecific Defenses 1. First Defense  SKIN 2. Second Defense  Inflammatory Response White blood cells (phagocytes) engulf and destroy bacteria Chemicals released to increase body temperature  FEVER Why is a fever beneficial to humans? Interferons are proteins that interfere with the growth of a virus

Specific Defenses Antigens (disease causing agents) trigger the immune response. Body produces B-lymphocytes and T-lymphocytes Humoral Immunity – B-cells produce plasma cells Plasma cells release protein antibodies specific to a type of antigen Memory B-cells now capable of quickly producing antibodies for a specific antigen.

Specific Defenses Cell-mediated Immunity – primary defense against its own cells or pathogens Upon infection, T-cells divide into Killer T-cells  track down and destroy antigens Helper T-cells  produce memory T-cells

Immune System Response Animation /animation__the_immune_response.htmlhttp://highered.mheducation.com/sites/ /student_view0/chapter22 /animation__the_immune_response.html

Diseases AUTOIMMUNE Diseases - The body attacks its own cells. Type 1 Diabetes: destruction of insulin producing cells in the pancreas Rheumatoid Arthritis: inflammation of joints and surrounding tissues

Diseases IMMUNODEFICIENCY Disease – immune system fails to develop properly AIDS Virus destroys helper T-cells weakening immune system functions

HIV and AIDS 1. HIV infects Macrophages Viral GP120 Protein  Protein receptor on Macrophage membrane 2. Viruses continually replicate within macrophages over many years New viruses exit cells through exocytosis Does not kill the Macrophages 3. Viruses undergo a mutation altering GP120 Protein Altered GP120 Protein  Protein receptor on T-cell membrane New viruses lyse(rupture) T-cell membrane and destroy T-cells 4. Long term degradation of host’s immune system