immune defense

• innate defense: non-specific
• surface barriers: skin, mucus
• protective chemicals

  • acid: stomach, skin
  • enzymes: saliva, mucus, tears
  • mucin: mucus to trap microbes
  • defensins: disrupt microbial membranes
• internal defenses

  • phagocytes: neutrophils, macrophages
  • natural killer cells
• antimicrobial proteins

  • interferons: interfere w/ viral replication
  • complement: punches hole in bacteria cell wall
• Fever

  • inhibit pathogen grown, throws bacterial enzymes out of optimum temp
  • speeds up immune response, optimum temp of WBC is slighter higher than normal body temp
  • if too high can lead to seizures, brain damage
• inflammatory response

  • chemical alarm signals: released by injured/stressed cells
  • histamine: inflammation
  • prostaglandins: pain
  • cytokines: chemotaxis
• inflammatory response

  • vasodilation: increased vascular permeability
  • smooth muscles relax, increased blood vessel diameter
  • more blood flow rushed to site of injury
  • increased swelling and heat
• Inflammatory response

  • leukocytosis: increase WBC count
  • chemotaxis: WBC attracted to cytokines
  • pus: mixture of WBC + pathogens
• adaptive defense: specific

  • specific: targets a particular antigen
  • systemic: full body protection
  • remembers: faster, stronger response to previously encountered pathogens
• adaptive defense

  • patrolling lymphocytes (T cells, B cells) antibodies
  • vaccines: dead/weakened pathogen injected to trigger adaptive response to provide long term immunity
• adaptive defense

  • passive immunity: transfer antibodies from another source

  1. maternal antibodies passed through placenta or from milk
  2. antivenin/antitoxin from blood plasma of immune donor