Pathology Flashcards
(546 cards)
What is acute inflammation?
A response of living tissue to injury. Inate, immediate, stereotyped, that acts to limit tissue damage
What is the purpose of inflammation?
Accumulation of fluid exudate and neutrophils in tissue
What can cause acute inflammation?
Microbial infections, hypersensitivity reactions, chemicals, necrosis, physica agents (heat, light, radiation)
What are the 5 signs of acute inflammation?
Redness, swelling, heat, pain and loss of function
What are the 3 main tissue level changes that occur in acute inflammation?
Change in blood flow, exudate of fluid, infiltration of inflammatory cells.
What is the first action that occurs in regards to the change in blood flow in acute inflammation?
Transient vasoconstriction (few seconds)
After transient vasoconstriction in acute inflammation what 3 things happen? And what signs of inflammation do they account for?
Vasodilation of arterioles then capillaries (heat and red), Increased permeability of blood vessels causing exudation and circulation slowing (swelling), increased concentration of RBC in small vessels and increased viscosity- stasis.
What causes vascular dilation, transient increase in vascular permeability and pain in acute inflammation?
Histamine
What releases histamine?
Mast cells, basophils and platelets
Mast cells, basophils and platelets release histamine in acute inflammation in response to what stimuli?
Physical damage, C3a, C5a, IL-1, factors from neutrophils and platelets
Histamine accounts for the immediate response in inflammation. What accounts for the persistant response in acute inflammation?
Leukotrienes and bradykinin (incompletely understood)
What determines fluid flow across vessel walls?
Balance of hydrostatic and colloid osmotic pressure
What pressures would increase fluid flow out of the vessel?
Increase in hydrostatic pressure, increase of colloid osmotic pressure of interstitium
In acute inflammation what leads to increase in hydrostatic pressure
Arteriolar dilation
In acute inflammation what causes an increase in colloid osmotic pressure of the interstitium?
Increased permeability of vessel walls leading to loss of protein.
Net fluid out of vessels causes what?
Oedema
What is the difference between a transudate and an exudate?
Transudate has the same protein level as plasma. An Exudate has more protein than plasma (inflammation)
What is the purpose of oedema?
INcreased lymphatic drainage.
When do we get a transudate instead of an exudate and why?
The fluid loss is due to hydrostatic pressure imbalance only. IN cardiac failure or venous outflow obstruction
What are the 5 mechanisms of vascular leakage in acute inflammation?
Endothelial contraction-> gaps Cytoskeleton reorganisation-> gaps Direct injury Leukocyte dependent injury Increased transcytosis (through cytoplasm)
What chemical mediators are responsible for endothelial contraction in the vascular leakage associated with acute inflammation?
Histamine, leukotrines
What chemical mediators are responsible for cytoskeleton reorganisation in acute inflammation?
Cytokines IL-1 and TNF
What chemical mediator induces iucnreased transcytosis in vascular leakage associated with acute inflammation?
VEGF
What plasma protein in particular is important in exudate formation associated with acute inflammation and why?
Fibrin– causes a meshwork localising the products of inflammation. Particulary important in serousal surfaces.