inflammation and repair Flashcards
inflammation
a complex reaction important in the process of repair that leads to the accumulation of fluid and leukocytes (white blood cells) in vascularized tissue. it is fundamentally a protective response that, if dysregulated, can cause harm
acute
short duration, most characterized by vascularized tissue. it is fundamentally a protective response that, if dysregulated, can cause harm
acute
short duration, mostly characterized by vascular changes that lead to edema of surrounding tissues and infiltration by neutrophils (also called polymorphonuclear leukocytes (PMNLs) or polys
chronic
longer duration, characterized by lymphocytes and macrophages (monocytes), tissue destruction by these cells and an attempt at at tissue repair via proliferation of blood vessels (angiogenesis) and connective tissue (fibrosis and scarring)
classic local signs of inflammation
rubor (redness)
swelling (tumor)
pain (dolor)
warmth (calor)
systemic signs of inflammation
fever
increased white cell count
enlargement of lymph nodes
associated microscopic events of redness & heat
dilation of microcirculation
associated microscopic events of swelling
permeability of vessels leads to exudate formation in tissues
associated microscopic events of pain
pressure on nerves by exudate, release of chemical mediators inducing pain
associated microscopic events of loss of normal tissue function
the result of swelling and pain
inflammatory response
1) injury
2) constriction of the microcirculation
3) dilation of small blood vessels
4) increase in permeability of small blood vessels
5) exudate leaves small blood vessels
hyperemia
increased blood flow that floods the capillary beds in the injured tissue
responsible for redness (erythema) and heat
exudate
inflammatory fluid formed as a reaction to injury of tissues and blood vessels
serous exudate
composed mainly of plasma fluids and proteins with a few white blood cells
purulent exudate (supparation)
contains tissue debris and many white blood cells, in additon to plasma fluids and proteins
fistula
a passage through the tissues which allows the excess exudate to drain
incision and drainage
surgical procedure for the removal of the excessive exudate
vasoactive factors
histamine seratonin bradykinin LTs/PGs PAF
chemotactic factors
C5a LTB formylated peptides lymphokines monokines
increase vascular permeability
edema
margination
the movement of the white blood cells to the periphery of the blood vessel walls
adhesion or pavementing
the adherence of white blood cells to the blood vessel walls
chemotaxis and emigration
the directed movement of white blood cells to the area of injury by chemical mediators which are called chemotactic factors (chemotaxis) and then the passage of white blood cells through the endothelium and wall of the microciruclation into the injured tissue (emigration)
phagocytosis and intracellular degradation
white blood cells ingest foreign material
extraceullar release of leukocyte producets
granules can release their contents into the tissue causing tissue damage
cellular events in acuste inflammation
1) margination
2) adhesion or pavementing
3) chemotaxis and emigration
4) phagocytosis and intracellular degradation
5) extracellular release of leukocyte products
exudation
neutrophils are the most prominent inflammatory cell in the first few hours (acute inflammation)
cytokines
activator; must be made in the cell –> further inflammation (attracting more cells); systemic effects like fever
prostaglandins
activator; must be made in the cell –> further inflammation; pain (aspirin)
histamine
activator; released from granules –> vasodilation and increased vascular perm. (anti-histamines)
complement
activator; increase in vascular perm.; attacts inflammatory cells; attacks microorganisms
kinins
activator; increase in vascular perm; pain
clotting
activator; coagulation
resolution
involves neutralization or removal of the chemical mediators of actue inflammation with subsequent normalization of vascular permeabiltiy and halting of leukocyte emigration; the combined efforts of lymphatic drainage and macrophage digestion lead to clearance of edema fluid, inflammatory cells and enecrotic debirs, resulting in the restoration of the inflammatory site to histologic and functional normalcy
when does resolution occur
1) the injury is limited or short lived
2) there has been minimal tissue destruction
3) the tissue is capable of regeneration
scarring (fibrosis)
extensive fibrinous exudates that cannot be absorbed are instead organized by ingrowth of connective tissue elements, resulting in a mass of fibrous scar tissue