Acute Inflammation Flashcards
What is acute inflammation a response to
The response of living tissue to injury
How do you know if a condition is related to inflammation
The condition will end in “itis”
Name some exogenous causes of inflammation
- Trauma
- Infection
- Chemicals
- Temperature
- Radiation
What are the endogenous causes of inflammation
- Anoxia
- Antigen/antibody complexes
- Body chemicals
- Metabolic products (urate crystals)
What are the macroscopic/cardinal signs of inflammation
- Redness (rubor)
- Swelling (tumor)
- Heat (calor)
- Pain (dolor)
- Loss of function (functio laesa)
What microscopic changes occur due to inflammation
- Initial constriction then dilation of vessels
- Increased blood flow
- Increased permeability
- Formation of exudate
- Migration of leukocytes through wall
- Oedema
What does increased permeability of blood vessels contribute to inflammation
- Enhances migration of cells
- Dilution of toxins
- Stimulate lymphatics/immune response
- Deposition of proteins e.g. fibrin to form mechanical barrier
What does the movement of WBCs from blood flow to focus of injury allow to happen
– margination
– pavementing
– transmigration/diapedesis
What is chemotaxis
movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.
What are the features and roles of neutrophil polymorphs in inflammation
- First cell to arrive
- Predominant cell for 6-24h
- Mobile, phagocytic and responds to chemotaxis
- Segmented nucleus, granular cytoplasm full of granules containing enzymes
What is the most common polymorph
neutrophils
Describe the features and roles of eosinophils
- Used especially in allergy and helminth infections
* bilobed, red granules
What are the features and roles of basophils/mast cells
- Acts very early
- Blue/pruple cytoplasm
- Degranulates with release of vasoactive amines
Where are monocytes/macrophages found
Circulating/tissue
Describe the features and morphology of monocytes/macrophages
- second main cell of acute inflammation
- predominate after 24h
- mobile, phagocytic, responds to chemotaxis
- attacks and clears up
- bean shaped nucleus, copious cytoplasm
Name some substances that can cause polymorphs to react by chemotaxis
- Bacteria
- fungi
- immune complexes
- toxins
- complement components
- lipoxygenase products
- white cell breakdown products
What are the 3 main stages of phagocytosis
- Recognition and attachment
- Engulfment
- Killing and Degradation
What processes happen in the recognition and attachment stage of phagocytosis
– mechanical contact
– opsonisation
What structures are formed in the engulfment stage of phagocytosis
– pseudopods
– phagosome
What is used to kill the contents of a phagosome
Lysosomal contents/enzymes
What processes are increased in the engulfment stage of phagocytosis
Glycolysis
RNA, protein and membrane synthesis
What is opsonisation
This is when an antibody that has attached to an antigen binds to a receptor on a polymorph/macrophage and elicits a response
Where do local mediators come from
Circulation
Intracellular - some are preformed and some are synthesised and released upon damage
Name some mediators that affect inflammation
Histamine Serotonin Lysosomal enzymes Prostaglandins Leukotrienes Cytokines
What is the role of mediators in inflammation
They regulate the generation, maintenance and resolution of the inflammatory response
Clinical features of acute inflammation?
- Pyrexia
- drowsiness
- lethargy
- leukocytosis
- decreased appetite
- acute phase proteins
What outcome is there from the resolution of acute inflammation
– clearance of injury
– clearance of inflammatory cells and mediators
– replacement of any injured cells
– normal function resumed
What outcome is there from the repair of acute inflammation
- some tissue lost may not be able to regenerate therefore replacement with granulation tissue and fibrosis
- likely less than ideal function
Describe suppurative inflammation resulting from acute inflammation
- pus is more exaggerated form of acute inflammation
- neutrophils, dead cells, bacteria and debris
- if walled-off and surrounded by a fibrous rim it becomes an abscess
Describe septicaemia resulting from acute inflammation
- organism gains access to lymphatics then blood or blood direct
- response heightened
- mortality high
What are the 5 potential outcomes of acute inflammation
Resolution Repair Chronic inflammation - repeated episodes Suppurative inflammation Septicaemia
