Innate Immunity: the inflammatory response Flashcards
is innate immunity specific or not nonspecific
- NON SPECIFIC (does not matter what the pathogen is)
What line of defense does it contain?
- first and second ONLY
what is included in the first line of defense?
- physical barriers
- chemical barriers
what are physical barriers?
- skin
- mucous membrane
- sections of the skin (ear wax, tears, sweat)
what are chemical barriers? (first line)
- stomach acid
- lysozymes in the eye
what cells are in the second line of defense? (inflammation)
- mast cells
- neutrophils
- macrophages
- NK cells
what are the function of mast cells & what does it cause?
- degranulate and release histamine = causing vasodilation & increased capillary permeability
- also helps w/ communication
what is the function of neutrophils
- phagocyte, first on site, most abundant
what are the function of macrophages?
- antigen presentation, phagocytosis, and immunomodulation (helps body stay homeostatic)
- turn into monocyte
what is the function of inflammation?
- prevent infection and damage from microorganisms (activate plasma proteins & dilute toxins)
- limit and control tissue damage ( stop it from spreading)
- stimulate the adaptive immune response
- promote healing
- rapid and non-specific
what are the general causes of inflammation?
- infection, cell damage, ischemia, nutrient deprivation, temperature extremes, radiation
- or body recognized a threat of one of those things
what are the 5 signs of inflammation?
- pain
- heat
- redness
- swelling
- loss of function
what role do plasma proteins system play in inflammation
- they are involved in 3 separate but interconnected systems
1. complement system = blood clotting
2. clotting system = plasma proteins = fibrous
3. the kinin system = vasodilation - end product of each sequence is a biologic effect that contributes to inflammation
what is the bradykinin system?
- protein that lowers blood pressure by widening blood vessels
- produced by the kinin system
- lowers BP by widening blood vessels and allows for water to leak into the surrounding tissue causing inflammation & pain
what are the plasma proteins involved with inflammation?
- interleukins
- interferon
- chemokines
- cytokines
what does interleukins (plasma proteins) do?
- produced primarily by macrophages and lymphocytes in response to a pathogen or stimuli by inflammation
what are interferon?
- protects against viral infections
- produced and released virally by infected host cells in response to viral double stranded RNA
what do the plasma protein chemokines do?
- induce WBC chemotaxis = the movement of WBC to site of injury
- produced by macrophages, fibroblast, endothelial cells
what does the complement system do for the process of inflammation?
- destroys the pathogens directly, activates or stimulates other components of inflammation
- also does opsonization and chemotaxis
what does the coagulation system do for the process of inflammation?
- forms a fibrinous meshwork at n injured or inflamed site (blood clot)
- fibrin is the main insoluble protein
what does the Kinkin system do for the process of inflammation?
- functions to activate and assist inflammatory cells
- has bradykinin: causes dilation of BV, pain. smooth muscle contraction, vascular permeability
what are the main cells involved in inflammation?
- phagocytes: neutrophils, macrophages, eosinophils
- mast cells
- platelets (clotting)
- endothelial cells (lining of BV)
what is the function of the neutrophils?
- high count = new infection
- predominate in early inflammatory responses
- 6 to 12 hours first on site
- ingest bacteria, dead cells, cellular debris
- cells short lived and become purulent exudate
what do monocytes become & when do they arrive @ site of infection ?
- they become macrophages
- arrive at inflammatory site within 3 - 7 days (along w/ all immune cells)
what do mast cells do?
- important cellular activator of inflammation
- granulated filled with histamine that gets released when they degranulate
what’s the function of eosinophils?
- they are mildly phagocytic cells
- defense against parasites and they regulate vascular mediators
what do platelets do?
- part of coagulation cascade
- promote wound healing
what do natural killer cells do?
- recognizing and eliminating cells infected with viruses and some function in eliminating cancer cells
what are 3 cellular components in inflammation
- histamine
- leukotrienes
- prostaglandins
what does histamine do?
- vasoactive molecule released from mast cells in degranulation
- vasodilation = increased blood flow into microcirculation
- causes retraction of endothelial cells lining the capillaries = increased vascular permeability
what do leukotrienes do in inflammation?
- they are a lipid mediator
- inflammation mediator synthesizes by mast cells
- have a histamine like reaction
- produces a slower, longer acting response
what is the function of prostaglandins in inflammation?
- lipids with hormone like properties
- inflammation mediator made by mast cells
- causes: increased vascular permeability, neutrophil chemotaxis, pain, fever
what are the 3 main events in inflammation?
- increased vascular permeability
- emigration of leukocytes
- phagocytosis
what happens in the first step of inflammation? (increased vascular permeability)
- vasodilation due to chemical mediators (histamine)
- endothelial cell retraction
- increased capillary permeability
- movement of fluid capillaries into tissues
what happens in step two of inflammation? (emigration of leukocytes)
- chemotaxis: directional migration of WBC along concentration gradient of chemotactic factors
- mechanisms for accumulating neutrophils and monocytes at the site of injury
- blood flow thru capillaries slows as fluid is lost and viscosity increases (makes thicker blood, slows process) = neutrophils roll / stick to endothelium = migration
- neutrophils and monocytes migrate through the capillary wall and site of injury
what is diapedeses?
- cells leaving
what happens in step three of inflammation? (phagocytosis)
- Performed by phagocytes
Neutrophils (early) and macrophages (later)
Eosinophils (mild) - Recognition & adherence = to eat (thx complement system bc opsonization)
- Engulfment (endocytosis)
- Fusion with lysosome
- Destruction = mini particles after the body takes away as waste
what is a phagocyte
process of a cell ingesting and disposing of foreign material (antigens)
what are the 2 types of inflammation?
- acute & chronic
what makes inflammation acute?
- short in duration
- lasting less than two weeks
what makes chronic inflammation?
- last 2+ weeks
- proceeded by an unsuccessful acute response
- Dense infiltration of lymphocytes & macrophages (if unable to remove [pathogen, granuloma formed)
what are the systemic manifestations of inflammation?
- fever
what is fever caused by?
- by exogenous (outside) & endogenous (inside) pyrogens
where does fever act on?
- directly on hypothalamus
what is Neutrophilic leukocytosis:
- increased number of neutrophils
what does increase of plasma proteins being synthesized do
- means muscle catabolism meaning the PT will feel weak due to muscle breakdown
what are the pros and cons of fever?
- Pro: microorganism can be killed by higher temp
- Con: may make the host more susceptible to microorganisms
whats the treatment for fever?
- Consider clinical picture or what’s happening in the PT body
- Antipyretics (Tylenol or ASA = fever reducers)
- Block prostaglandins
what are the local manifestation of inflammation? classic symptoms
- redness
- heat
- swelling
- pain
- loss of function
what is serous exudate?
- serous = watery
- exudate = fluid leaves the site of infection
- watery exudate that indicates possible early inflammation
what’s fibrinous exudate?
- cloudily / thick
- thick, cloudily exudate, stands of fibrin
purulent exudate?
- indicates bacterial infection
- yellow, thick, gross
- pus: poaque, indicates bacterial infection
what causes abscess formation?
- walled off lesion usually w/ purulent exudate
- BV are walled off
