Session 1: Inflamation- Acute And Chronic (Lecture 11) Flashcards
What is inflammation?
The reaction of vascularised tissues to cell injury or death
What are the three main goals of inflammation?
Reduce the effects of an injury or infection
Remove damaged tissues
Generate new tissue and repair it
How does inflammation achieve its goals?
By diluting, destroying, and neutralising the harmful agents or the damaged tissue
Name three types of inflammatory stimuli.
Infectious
Physical
Chemical
What are the main vascular reactions of acute inflammation?
Increased blood flow (Vasodilation) and increased vascular permeability
What causes redness and warmth during inflammation?
Increased blood flow due to arteriolar vasodilation
What is stasis?
Small vessels packed with red blood cells due to increased concentration of red cells in the blood
What is margination?
Leukocytes accumulating along the vascular endothelial surface
What is an exudate?
Movement of protein-rich fluid and blood cells into the extravascular tissues due to increased osmotic pressure of the interstitial fluid
What is a transudate?
Movement of low protein fluid and no blood cells into the extravascular tissues due to increased hydrostatic pressure
What are the main jobs of leukocytes during inflammation?
Ingest offending agents
Kill bacteria
Eliminate necrotic tissue
List the four steps of leukocyte recruitment from the vascular lumen to the extravascular space.
Margination and rolling along the vessel wall
Firm adhesion to the endothelium
Transmigration between endothelial cells (diapedesis)
Migration in interstitial tissues (chemotaxis)
What is the role of histamine in inflammation?
A vasoactive amine released from mast cell granules
What is the role of Reactive Oxygen Species (ROS) in inflammation?
Destroy phagocytosed microbes and necrotic cells
What is the role of the complement system in inflammation?
Opsonise particles for phagocytosis, and punch holes in the membranes of invading microbes
What are the roles of C3a and C5a?
Vasodilation and Chemotaxis
What is the role of C3b?
Phagocytosis
What does bradykinin cause?
Increased vascular permeability, arteriolar dilation and bronchial smooth muscle contraction
What are the main features of chronic inflammation?
Infiltration with mononuclear cells (macrophages and lymphocytes)
Tissue destruction
Repair, involving new vessel proliferation (angiogenesis) and fibrosis
What are three causes of chronic inflammation?
Persistent infections
Autoantigens causing self-perpetuating immune reaction
Prolonged exposure to nondegradable exogenous materials
What are the two major pathways of macrophage activation?
Classical and alternative
What does the classical pathway of macrophage activation induce?
The production of lysosomal enzymes, NO, and ROS
What is the principal role of alternatively activated macrophages?
Tissue repair
What is granulomatous inflammation?
A distinctive pattern of chronic inflammation characterised by aggregates of activated macrophages
