acute inflammation Flashcards
Causes of acute inflammation
- Microbial infection
- hypersensitivity reactions (ie allergic response)
- physical agents eh burns, piece of glass
- chemical agents eg HCL acid
5 indicators of acute inflammation
- redness
- Heat
- swelling
- loss of function
- Pain
What causes swelling in acute inflammation?
oedema (ie the collection of exudate in tissue) plus increase volume due to inflammatory cells
what causes the redness?
dilation of blood vessels
why might experience pain?
stimulation of nerve endings by pressure and chemical mediators
what allows capillary beds to open?
capillary sphincters open
what continuously removes the exudate?
lymphatic system
what happens to the blood vessels during the vascular phase?
they dilate and become more leaky/ permeable
describe the protein content of exudate and the effect out has on the water balance
the exudate has a very high protein content (almost at that of blood plasma), this reduces the water concentration gradient between the blood and the tissue fluid. This means there is a net flow of fluid out of the capillaries resulting in swelling.
name a protein you will find in exudate
immunoglobin
function of immunoglobulins
destroy invading pathogens
What is the transudate?
The extravascular fluid that exists around blood capillaries due to high hydrostatic pressure forcing it out
during an acute inflammatory response does the permeability of capillary walls increase or decrease?
incr
does the transudate have a low protein cont?
yes
describe chemotaxis
movement along a concentration gradient- from where there is a low conc of a chemical to where there is a high conc of a chemical
how do the receptors on the surface of the neutrophil help it carry out chemotaxis?
as the cell moves from an area of low conc of the signally substance to an area of higher conc, more and more receptor sites get filled.
name some chemostatic compounds
bacterial products, products of neutrophil activity
What causes the reaction to spread from injured areas to uninjured areas?
chemical substances which are released from cells and plasma
5 things chemical mediators can cause
- vasodilation
- emigration of neutrophils
- chemotaxis
- increased vascular permeability
- itching and pain
name the 4 enzymatic cascade systems which help mediate the inflammatory response
- complement system
- the kinins
- the coagulation factors
- fibrinolytic system
what is necrotic tissue?
dead tissue
what do neutrophils do to necrotic tissue?
degrade it
what 3 things do neutrophils do?
- ingest and kill invading agents (by phagocytosis)
- degrade necrotic tissue
- produce chemical mediators, toxic oxygen radicals and enzymes
what increases the recognition of mircroorganisms?
opsonins
Name 3 major opsonins
- Fc fragment of IgG
- C3b
- collectins
what are collectins?
opsonins that are plasma proteins which bind to microbial cell walls
what are opsonins?
molecules that attach to pathogens to help phagocytic cells take them up
what is suppuration?
the process of pus forming
What do you find in pus?
neutrophils, bacteria, cellular debris
What is an abscess?
A collection of pus surrounded by a membrane of sprouting capillaries, neutrophils and the occasional fibroblast
What is an ulcer?
A local defect/ excavation of the surface of an organ or tissue that is produced by the sloughing off of inflammatory necrotic tissue
What benefit does swelling have?
It dilutes the toxins in the infected area, they are then carried away by lymphatics
the benefit of fibrin formation
stops movement of microorganisms from site of infection
describe netosis
the process whereby neutrophils expel their DNA which traps bacteria and prevents them from moving away
How does an inflammatory response stimulate an immune response?
Lots of fluid exudate floods the area, it will pick up antigens (on activated WBC /loose/on pathogens) and be carried away by local lymph nodes where the antigens can stimulate an immune response
name some harmful effects of acute inflammation
- digestion of normal tissues (due to release of lysosomes )
- swelling in a confined space eg laryngeal oedema, brain swelling
- inappropriate inflammatory response eg type 1 hypersensitivity
- excessive release fo cytokines resulting in hyperpyrexia, shock and death
