immune system 1

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immune system 1
2013-01-17 10:19:20
immune bio

immune bio
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  1. pathogen
    • organism or virus tt causes a disease
    • e.g. viruses, bacteria, fungi, protozoa, flatworms
  2. why aren't antibiotics effective on viruses?
    • antibiotics block specific metabolic pathways o bac. cells leaving euk cells unharmed
    • viruses invade host cells = eukaryotic, uses host cell's metabolic pathways to reprod
    • antibiotics dont block processes euk cells
  3. how does body recog. own tissues?
    • major histocompatibility complex (MHC)
    • MHC antigens protein molecules in phospholipid bilayer
    • allows immune system to recog
  4. clotting process
    • injury to lining blood vessels exposes connective tissue, platelets adhere (thrombocytes)
    • platelet releases chemicals that make nearby platelets sticky
    • release o clotting factors fr platelets, damaged cells, plasma } mix together¬† and activate
    • prothrombin precursor to thrombin enzyme activates
    • soluble fibrinogen precursor to fibrin: fibrous protein
    • platelet plug forms = emergency protection against blood loss
    • reinforced by clot fibrin when vessel damage = more severe
    • fibrin clot with trapped red blood cells
  5. what are six steps of how phagocyte destroys microbes?
    • some leukocytes¬†are phagocytes, ingest pathogens in blood/body tissue
    • detection
    • ingestion
    • phagosome forms
    • fusion with lysosome
    • digestion
    • discharge
  6. detection
    • detects microbes by chemicals they give off
    • sticks microbes to its surface
    • MHC antigens
  7. ingestion
    microbe enguled by phagocyte wrapping pseudopodia around -> vesicle, endocytosis
  8. phagosome forms
    phagosome (phagocytic vesicle) formed -> encloses microbe in membrane
  9. fusion w/ lysosome
    phagosome fuses with lysosome (contains powerful enzyme tt digests microbe)
  10. digestion
    microbes broken down by enzymes into their chemical constituents
  11. discharge
    indigestible material dischagrged fr phagocyte cell
  12. b cells
    • mature in Bone marrow
    • two types: memory + plasma cells
  13. t cells
    • mature in thymus gland
    • 3 types: helper T cell, cytotoxic T cell (killer t cell), suppressor T cell (calls off immune response)
  14. antigens
    • foreign molec. tt elicit specific response by lymphocytes
    • e.g. antibody production
    • such as surface molec. o viruses, bacteria, fungi, pollen, transplanted tissue
    • antigen is a large molecule (protein, glycoprotein, lipoprotein or polysaccharide) on the outer surface of a cell.
    • All living cells have these antigens as part of their cell membrane or cell wall.
    • for cell-to-cell communication
  15. antibody
    • protein secreted by b cells (plasma cells) recognize + bind specific antigens
    • destroy pathogen and antigen infections
    • antibody (immunoglobulin) a protein molecule that can bind specifically to an antigen
  16. two main types mechanisms used by body for defense?
    • non-specific resistance: def. tt protect humans fr any pathogens
    • specific resistance: targets specific pathogens carried out by lymphocytes + called immune response
  17. skin and mucous membrane in def against pathogens
    • ref two main types mechanisms for body defense
    • skin: physical barrier, tough diff to penetratenature
    • pop. harmless microbes inhibit growth pathogenic microbes
    • sebaceous glands secrete chem-> lactic acid + fatty acids = skin acidic = prev bacterial growth
    • tears + saliva help wash bacteria away
    • mucous membranes: found in lining respiratory, urinary, reprod + gastrointestinal tracts
    • mucous contains lysosome destroys many bac
    • respiratory tract pathogens caught in sticky mucous + cilia then push mucus + bac up out o trachea -> swallowed/digested