Acute inflammation Flashcards
What are the 5 cardinal features of acute inflammation?
- Calor (Heat).
- Rubor (Redness).
- Tumor (Swelling).
- Dolor (Pain).
- Functio Laesa (Loss of Function).
List 4 causes of acute inflammation
- Infection.
- Tissue necrosis.
- Foreign bodies.
- Immune reactions.
How specific is the immediate response to a pathogen?
The immediate response activates the innate immune system and therefore has limited specificity.
Name 3 cell types which act as sentinel cells in tissues ready to react to invading microorganisms or to cell damage.
- Macrophages.
- Dendritic cells.
- Mast cells.
What are the molecules which pathogens and damaged cells produce which can activate cells of the innate immune system?
PAMPS and DAMPS (Pathogen Associated Molecular Patterns and Damage Associated Molecular Patterns)
What is the main cytokine produced by sentinel cells when they are activated by DAMPs and PAMPs?
Interleukin 1 (IL-1).
List the 5 steps of acute inflammation (the 5 R’s)
Recognition (of the injurious agent). Recruitment (of leucocytes). Removal (of the agent). Regulation (of the response). Resolution.
What is the difference between a cytokine and a chemokine?
Cytokines are proteins produced by many cell types that can mediate and regulate inflammatory reactions. Cyto means cell and kine refers to kinesis or movement. Chemokines are chemotactic cytokines. These are produced as a chemical cloud which spreads out from the source of inflammation and can attract specific white blood cells.
List the 5 important mediators of acute inflammation.
- Hageman factor (Factor XII).
- The complement system.
- Mast cells.
- Arachidonic acid metabolites.
- Toll-like receptors.
What is the Hageman Factor?
This is a factor produced by the liver as an inactive protein. It circulates in the blood stream until it is activated by exposure to collagen.
What is the link between the clotting system and the inflammatory system?
Hageman factor activates the coagulation cascade and also activates the kinin system.
What are the 3 main functions of bradykinin?
- Vasodilation.
- Increased vascular permeability.
- Pain.
What is the Complement System?
A system of pro-inflammatory proteins produced by the liver which circulate as inactive precursors until they are activated by 1 of 3 pathways.
Name the 3 complement system activation pathways and explain how they are activated.
- Classical pathway. Activated by antigen binding to IgG or IgM which activates C1.
- Alternative pathway. Activated by microbial components directly.
- Mannose-binding lectin pathway. Activated by mannose-binding lectin binding to mannose on the surface of a bacterium.
List 4 consequences of complement system activation.
- Formation of anaphylatoxins (C3a, C4a + C5a) which cause histamine to be released from mast cells. C5a is a chemotactic + activation agent for neutrophils, monocytes, eosinophils and basophils.
- Opsonisation. C3b is the main opsonin (an ‘eat-me’ signal for neutrophils and macrophages which have C3b receptors).
- Cell lysis. The final stage of the complement cascade results in the formation of a membrane attack complex (C5b, C6, C7, C8 and C9) flooding the cell with water and ions and causing lysis.
- Immunoglobulin clearance. Removal of immune complexes from the circulation.