-
physical barriers
- skin
- hair
- mucous membranes
-
flushing
effective in removing microbes out of your body but exposes others to thos microbes
-
mucociliary escalator
keeps lungs clea
-
lysosomes
(chemical barriers)
- breakdown peptidoglycan
- won't work on endospores, mycobacteria, gram negative, and acid fast bacteria
-
sweat
(chemical barrier)
- antimicrobial because it's a a hypertonic solution
- pH change
-
defensins in mucosa
(chemical barriers)
- like phospholipids (polar and nonpolar region)
- they can insert directly into the phospholipid bilater and eventually interact with each other
- works best on gram negative, mycobacterium, enveloped viruses, and protists
-
iron binding proteins
(cellular barrier)
- keep iron from bacteria
- lactoferin, gerritin, transferris
-
sebum
(chemical barrier)
- oils on our skin
- tend to be acidic
- fatty acids also have the ability to inhibit growth
-
granulocytes involved
- basophiles: release histamine (dilates capillaries)
- mast cells: found in tissues: release histamine (associated with allergies)
- eosinophile: allergy infections and worm infections -- turn of inflamation responce
- neutrophils: phagocyte -- clean up debris (respond quickly)
-
agranulocytes involved
- monocytes: macrophages -- most aggressive in tissue
- natural killer cells: programmed to recognize cells that aren't healthy
- lymphocytes
-
innate defenses
- act against any type of invading agent
- perform function before adaptive defnses are activated
- however the innate actions are necessary to activate the adaptive system`
-
blood
- blood flowing out of the wound helps remove microorganisms
- blood clotting and swelling seals off site
-
inflammation
- body's defense responce to tissue damage from microbial infection
- also responds to cuts and abrasian, burns, sunburn, phenols, acids, alkalis and allergies
- increase calor, rubor, tumor, and dolar
-
fever
- increase in body temperature
- accompanies inflammation
- temperature regulated in hypothalamus
- -raises temperature above optimum temperature for the growth of many pathogens -- slows the rate of growth
- -higher temperatures makes some microbial enzymes or toxins to become inactive
- -heightens immune responces by increasing rate of chemical reaction
- -phagocytosis is enhanced
- -production of antiviral interferon is icreased
- -breakdown of lysosomes increased (causing death in infected cells
- -the patient is more likely to rest
-
interferons
- "interfere" with virion replication in other cells
- breaks down proteins
- alpha and beta: synthesis occurs only after a virus infects a cell.
- -synthesized and released to adjacent unaffected cells which then stimulates those cells to produce antiviral proteins within the uninfected cell.
-
complement
- regulatory proteins
- general functions: 1)enhanced phagocytosis by phagocytes 2)lyse microorganisms, bacteria, and enveloped viruses directly 3)generate peptide fragments that regulate inflamation and immune responces
- begin to work as soon as an invading microbe is detected
- works as a cascade
- plasma proteins floating around in an inactivated form
-
natural killer cells
- kill certain target cells
- major histamine complex on surface of cells to let macrophages know they're one of them
- if the cell doesn't have that they will attack (virus infected cells and cancer cells)
- always there ready to attack
-
leukocyte endogenous mediator (LEM)
- pyrogen
- decreases iron gut absorption
- increase iron storage in tissues
- ---less available to microbes
-
classical pathway
begins when antibodies bind to antigen
-
alternative pathway
activated by contac between complement proteins and polysaccharides on the pathogen surface
-
opsonization
- complement
- --during phagocytocis some bacteria can prevent phagocytes from adhering to them
- the complement system counteracts by binding opsonins to the the surface of the infectious agent (allows adherence)
-
membrane attack complexes
- complement proteins produce lesions in the cell membrane of microorganisms - causing cellular contents to leak out
- the complement comlexes combine withint the cell and form a pore consistuting the MAC
- responsible for direct lysis
- host plasma membranes contain proteins to protect against MAC lysis
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