Inflammation Flashcards
Define inflammation
Reactions of living vascularised tissue to sub-lethal injury
What are the three types of inflammation and what are the main cell involved?
Acute; transient and early responses to injury, involves release of chemical mediators
-Neutrophil
Chronic: inflammation of prolonged duration, usually due to persistent injury causing agent.
- Macrophages
- lymphocytes
- neutrophil exudate
Granulomatous (type of chronic inflammation):FORM of chronic inflammation: shows granuloma formation. Clusters of macrophages. Involves specific immune reaction T cells.
-Lymphocytes and Macrophages
What are the clinical features of acute inflammation?
LOCAL
- Rubor *redness
- calor * heat
- tumor *swelling
- dolor *pain
- Functio Leasa- loss of function
SYSTEMIC:
Fever
Shock
What causes:
- Calor
- Tumor
- Rubor
- Loss of function
Calor: caused by histamine mediated vasodilation
Tumor: oedema, increased fluid in interstitial fluid
caused by histamine mediated increase in permeability of vessels
Rubor: blood flow isn’t as fast so you get redness
Loss of Function: due to swelling and pain
What triggers histamine release and what is it and what effect do histamines have?
- Vasoactive amine
-produced by mast cells
-packaged into granules inside mast cells- when antigen binds to IgE on the surface of mast cells to the Fc receptor on mast cells - causes cross-linking and degranulation
Histamines cause: vasodilation + increased vascular permeability
What is an exudate?
Fluid with high protein content and cellular debris, which leaves blood vessels and deposits in tissues or on tissue surfaces, usually as a result of inflammation
What is a transudate?
Fluid escape from vessels due to disturbances in hydrostatic and colloid osmotic pressure – NOT CAUSED BY INFLAMMATION:
- Low protein
- Cell poor
- Low specific Gravity
What are the functions of exudate?
- Fluid: dilutes pathogen and allows soluble mediators to spread
- Fibrin: walls off pathogen to stop it spreading. Gives inflammatory cells substrate to hold on to/migrate through
What are the 4 types of exudates and how do they differ?
Serous – fluid filled – lowest protein content of the three exudates
Fibrinous – high fibrin content – more due to traumatic injury
Purulent – pus filled –combination of fibrin, inflammatory cells, debris and fluid.
Haemorrhagic
What is the main histological feature of acute inflammation?
- Lots of neutrophils, these kill bacteria and recruit more cells, and degranulation.
- there will also be eosinophils and mast cells
What are the steps in the leukocyte exiting the vessel lumen ( extravasation)
- Margination ( cells being pushed to the edges of the vessels)
- Rolling
- Adhesion : bind to endothelial cells through selectins on neutrophils, selectin bonds loose, causing neutrophil to roll and slow down which fixes it to the vessel wall as more permanent bonds are formed.
- Transmigration (diapedesis) across endothelium through vessel wall: neutrophil dissolves basement and enters interstitium
- migration through tissues: chemotaxis, flow to site of inflammation.
What are eosinophils and mast cells important for
Important in allergic diseases ( both mast and eosinophils)
-and parasitic causes of inflammation (eosinophil ONLY)
Define chronic inflammation and what is it caused by?
inflammation of prolonged duration in which active inflammation, tissue destruction and attempts at repair occur simultaneously
caused by:
-persistent damage e.g. persistent infection, prolonged exposure to toxic agent..
What are the three main cell types involved in chronic inflammation and these will also be abundant for histological features?
Macrophages
Lymphocytes
Plasma Cells
What is an important difference between acute and chronic inflammation?
Acute inflammation produces an exudate whereas chronic inflammation doesn’t, necrosis is also not very prominent as it is in acute, and granulation tissue is formed while trying to repair in chronic.