Inflammation and Healing Flashcards
What is acute inflammation?
Initial and transient series of tissues reactions to injury
5 causes of acute inflammation
Trauma, heat, cold, UV, radiation, microbial infections, chemicals, tissue necrosis, hypersensitivity reactions
4 outcomes of acute inflammation
Resolution, progression, suppuration, organisation
3 processes involved in acute inflammation
Changes in vessel calibre, increased vascular permeability and formation of fluid exudate, formation of cellular exudate - emigration of neutrophil polymorphs into extravascular space
4 physical characteristics of acute inflammation
Rubor, calor, tomur, dolor (also loss of function)
Features of the fluid exudate and what it contains
High protein content - up to 50g/L - immunoglobulins, coagulation factors such as fibrinogen
4 steps of neutrophil emigrations
Margination into plasmatic zone, adhesion to endothelial cells, pass between endothelial cells, pass through basal lamina and migrate into adventitia
6 chemical mediators released by cells
Histamine, lysosomal compounds, prostaglandins, leukotreines, serotonin, chemokines
What effects does histamine have in acute inflammation?
Causes vascular dilatation and the immediate transient phase of increased vascular permeability
Where is histamine stored?
Stored as preformed granules mainly in mast cells but also in basophil and eosinophil leucocytes and platelets
Name the 4 enzymatic cascade systems present in plasma
Coagulation factors, kinin system, complement and the fibrinolytic system
4 advantages of these systems
Each step results in amplification of the response, it is safer to have inactive precursors than active mediators, more regulators can modulate response, each step results in end products with possible different activities
3 ways the complement system can be activated
In tissue necrosis enzymes capable of activating it are released, during infection formation of antigen-antibody complexes activate it via the classical pathway, endotoxins of Gram negative bacteria can activate it via the alternative pathway, products of kinin and fibrinolytic pathway
2 features of a neutrophil polymorph
Multilobulated nucleus, fine granules
Define organisation
Organisation of tissues is their replacement by granulation tissue as part of the repair process
4 causes of chronic inflammation
Progression from acute, primary chronic inflammation (crohns/sarcoidosis/autoimmue diseases), transplant rejection, organisms that are resistance to phagocytosis
3 characteristic cells of chronic inflammation
Lymphocytes, plasma cells and macrophages
5 activities of cytokines
Recruitment of macrophages, production of inflammatory mediators, recruitment of other lymphocytes, destruction of target cells, interferon production
What is a granuloma?
An aggregate of epithelioid histiocytes
What is an epithelioid histiocyte?
Activated macrophage with large vesicular nucleus and eosinophilic cytoplasm
When do histiocytic giant cells form?
When particulate matter which is indigestible by macrophages accumulates (silica or bacteria such as tubercle bacilli)
3 types of histiocytic giant cells and one characteristic or each
Langhans giant cells - horseshoe arranged nuclei, Foreign body giant cells - randomly scattered nuclei, Touton giant cells - central ring of nuclei/clear peripheral cytoplasm due to accumulated lipid
What are the 3 populations of cells according to their potential for renewal and an example of where you would find each
Labile - good capacity to regenerate, eg surface epithelium
Stable - divide at slow rate normally but retain ability to divide when necessary, eg hepatocytes
Permanent - no effective regeneration, eg nerve cells
3 mechanisms of pain associated with acute inflammation
Distortion of tissues due to oedema, pus under pressure in an abscess cavity, chemical mediators (bradykinin/prostaglandins/serotonin)
