Inflammation Flashcards
Name the macroscopic and microscopic features of acute inflammation.
Macroscopic - rubor, dolor, calor, tumor, loss of function
Microscopic - changes in blood flow, exudation of fluid into tissues, infiltration of inflammatory cells
What is acute inflammation?
The rapid response of living tissue to injury, in order to limit tissue damage and deliver mediators of host defence to the site of injury.
What is chronic inflammation?
The chronic response to injury, associated with fibrosis.
Which mediators are responsible for changes in blood flow in acute inflammation?
First 30 mins - histamine (from mast cells), C3a, C5a, neutrophils. Persistent response (after 30 mins) - leukotrienes and bradykinin
What are the actions of C3a an C5a?
Vasodilation (increased blood flow) and increased permeability
What does Starling’s Law state?
That the fluid movement across the capillary wall depends on the balance between hydrostatic pressure gradient and oncotic pressure gradient.
What is the difference between transudate and exudate?
Transudate is fluid loss due to increased hydrostatic pressure, and the protein content is the same as plasma.
Exudate is fluid loss due to decreased oncotic pressure, and the protein content is higher than plasma.
Name the 4 stages of infiltration of neutrophils during acute inflammation.
Margination
Rolling
Adhesion
Emigration
What is chemotaxis?
The movement along a concentration gradient of chemoattractants e.g. C5a.
What is diapedesis?
The movement of blood cells through intact capillary walls.
What is emigration?
The movement of WBC through intact capillary walls (the diapedesis of WBC).
What is oxygen dependent killing?
When a phagocyte ingests a pathogen there is an increase in oxygen content in the cell, known as the respiratory burst. This produces ROS - either superoxide (O2-) or hypochlorite (HOCl).
What is oxygen-independent killing?
3 types:
- lysozyme - break down bacterial cell wall
- electrically charged proteins - damage bacterium’s membrane
- proteases and hydrolytic enzymes - digest bacterial proteins
What is resolution?
When the changes of acute inflammation gradually reverse i.e. Vascular changes stop, neutrophils no longer marginate, vessel permeability and diameter return to normal.
What is a giant cell?
A multinucleate cell produced by the fusion of macrophages due to frustrated phagocytosis (they can’t get rid of their pathogens).
