MOD 2.1 - Acute Inflammation Flashcards
What are the causes of acute inflammation? (5)
- Microbial infections e.g. Pyogenic organisms (staphylococcus)
- Hypersensitivity reactions (acute)
- Physical agents e.g. Heat
- Chemicals
- Tissue necrosis
What are the clinical features of acute inflammation?
- Rubor (redness)
- Tumor (swelling)
- Dolor (pain and loss of function)
- Calor (heat)
What are the two phases of acute inflammation?
- Vascular
- Cellular
Describe the changes in blood flow during the vascular phase
- Transient vasoconstriction of Arterioles
- Vasodilation of Arterioles and capillaries
- Increased permeability of blood vessels
- Stasis
What happens as a result of vasodilation of Arterioles and capillaries during the vascular phase?
Increases blood flow which leads to heat and redness
What happens as a result of an increased permeability of blood vessels during the vascular phase?
- Exudation (seeping) of protein rich fluid into tissues from plasma
- Slowing of circulation which leads to swelling
What is stasis?
The stoppage or slowing of blood flow
What happens as a result of stasis during the vascular phase?
Increased concentration of red blood cells which increases blood viscosity
Give an example of a chemical mediator of changes in blood flow
Histamine - released as an early response (first 1/2 hour)
What causes a release of histamine and what is it released from?
- Released as a response to stimuli e.g. Physical damage or immunologic reactions
- Released from mast cells, basophils and platelets
Describe the changes of histamine (3)
- Vascular dilation
- Transient increase in vascular permeability
- Pain
What is acute inflammation?
The response of living tissue to injury that is initiated to limit tissue damage
What are the chemical mediators for a persistent response?
Non-specific, there’s lots of different types
What are the determining factors of fluid flow?
Hydrostatic and colloid osmotic pressure comparing plasma and interstitial fluid
What happens as a result of an increase in hydrostatic pressure?
There is an increase in movement of fluid out of the vessel
What happens as a result in an increase in osmotic colloid pressure?
There is an increase in flow out pressure therefore increasing the protein concentration in the interstitium
What happens due to an increase in vascular permeability?
- Increases concentration of protein in the interstitium therefore causing an outward net flow of fluid
- Leads to oedema (exudate)
What is oedema and what are the two types?
- An increase of fluid in tissue spaces
- Transudate and Exudate
Describe Transudate oedema
The protein content of the oedema fluid is THE SAME AS the protein content of the plasma
Describe exudate oedema
The protein content of the oedema fluid is HIGHER than the protein content of the plasma
What are the mechanisms of vascular leakage? (5)
- Endothelial contraction (forms gaps between cells)
- Cytoskeletal reorganisation (forms gaps between cells)
- Direct injury e.g. Toxic burns, chemicals
- Leukocyte dependent injury (enzymatic/ toxic O2 species)
- Increased Transcytosis (movement of macromolecules across a membrane)
Describe the cellular phase of acute inflammation
Infiltration of polymorphs (multi lobed nuclei) to the inflamed area
What are the four steps in the infiltration of neutrophils?
- Margination
- Rolling
- Adhesion
- Emigration
What happens during the Margination step of neutrophil infiltration?
Neutrophils line up at peripheries of blood vessels
