acute inflammation Flashcards
what is inflammation?
the consequences of another effect: e.g. microbial infections, hypersensitivity reactions, physical or chemical agents
what are some of the characteristics of inflammation?
red - due to dilation of the blood vessels;
hotness - due to blood vessel dilation; swollen - due to oedema and contribution from inflammatory cells; painful - stimulation of local nerve endings and chemical mediators; can also be a local or systematic loss of function
what are the two phases of inflammation?
vascular phase: dilation and increased permeability of blood vessels;
exudative phase: fluid and cells escape from permeable venules
what is one of the most important blood cells in inflammation?
neutrophils
what is the difference between transudate and exudate?
transudate is normal interstitial fluid that leaks from capillaries due to hydrostatic pressure but returns via venules; exudate is the fluid that leaks from blood vessels during inflammation. with transudate, there is no net flow but with exudate there is; with exudate there is an increased permeability of blood vessels compared to in transudate; in transudate there is a low protein content but there is a high protein content in exudate
what kind of proteins does exudate contain?
immunoglobins - destroy invading organisms
fibrinogen - synthesises fibrin
what happens to the exudate once it has leaked from the blood vessels?
It is picked up by lymph vessels and taken to lymph nodes where it is used in the immune response.
what are the chemical mediators in inflammation and what is their purpose?
chemical mediators include histamine and bradykinin. They stimulate gaps to form between the endothelial cells of 0.1-0.4 microns in post capillary venues. The endothelial cells are not damaged from this and return to normal.
what happens to the exudate when it reaches the lymph nodes?
The leucocytes located there (mainly lymphocytes) produce specific antibodies
what is lymphangitis?
inflammation of the lymph vessel
what is lymphadenitis?
inflammation of local lymph nodes
margination
when neutrophils roll on the blood vessel wall and attach. (before they squeeze out)
the accumulation of what type of leucocytes in the ECM is a key feature of acute inflammation?
neutrophils
how long do neutrophils last for?
24 hours
what are neutrophils main role in the immune response?
to phagocytose and digest invading pathogens
what is chemotaxis?
the movement of cells in the direction of increasing concentration of a chemical mediator
how do neutrophils detect the chemical mediators?
via receptors on their surfaces
what are opsonins?
chemicals which invading pathogens are coated in which help leucocytes to bind to them and greatly increase phagocytosis
what is a characteristic of serous inflammatory response
protein rich fluid exudate (e.g. conjunctivitis)
what is a characteristic of catarrhal inflammatory response
mucus hyper secretion (e.g. common cold)
what is a characteristic of fibrinous inflammatory response
exudate is plentiful in fibrin (eg pericarditis)
what is a characteristic of haemorrhagic inflammatory response
severe vascular injury (e.g. pancreatitis)
what is a characteristic of suppurative inflammatory response
production of pus (e.g. abscesses)
what is a characteristic of membranous inflammatory response
epithelium coated in fibrin
what is a characteristic of pseudomembranous inflammatory response
superficial mucosal slough (eg C. difficile)
what are some of the beneficial factors of acute inflammation?
dilution of toxins, entry of antibodies, increase delivery of materials to lymph nodes, usually results in resolution
what are some of the harmful factors of acute inflammation?
digestion of normal tissue, swelling can cause problems (e.g. in the brain)
