Acute Inflammation Flashcards
Name the four causes of acute inflammation
Microbial Infections
Hypersensitivity reactions
physical agents
chemical agents
What are the 5 main things to look for in regards to acute inflammation
- Red - dilation of the blood vessels
- Hot - peripheral increase in temperature due to increased blood flow (hyperaemia)
- Swollen - due to oedema and contribution from inflammatory cells
- Painful - Stimulation of nerve endings by pressure and chemical mediators
- Loss of function
What are the two phases of acute inflammation
Vascular phase = dilation and increased permeability
Exudative phase = fluid and cells escape from permeable venules
What cell type is characteristic of acute inflammation
neutrophil Polymorph, in the extracellular space
What is capillaries import to note
They are not always open, during acute inflammation the precapillary spinchter is OPEN meaning most capillaries are full. During a normal homeostasis these remain closed.
What happens to plasma proteins during acute inflammation
There is a NET flow out of the capillary as the plasma proteins move out due to increased permeability of capillaries
What is the Exudate composed of? (the thing that leaves the capillary due to increased permeability
High protein content (including immunoglobulins = for the destruction of invading bodies)
Fibrinogen > Fibrin (this occurs on extravascular contact - inflamed organ surfaces are commonly covered in fibrin)
High turn over as this is continuously removed by the lymphatic system
Give me some features of exudate
– Net flow out
– Increased vascular permeability
– High protein content
Give me some features of transudate
– Net flow out
– Normal vascular permeability
– Low protein content
What does an increased vascular permeability mean?
- due to chemical mediators like histamine and bradykinin
- stimulation of endothelial cell cytoskeleton by said mediators
- confined to post capillary venules
- Transient, intracellular gaps (approx 0.1 - 0.4 microns)
Endothelial cells are NOT DAMAGED in the process
What happens in the lymphatic system during inflammation
- Becomes dilated
- Drain fluid from exudate
- Antigens carried to lymph nodes
- Recognised by lymphocytes
Lymphangitis
infection of the lymphatic channel
lymphadenitis
Inflammation of a lymphatic gland
What do chemotactic compounds include
- Bacterial products
- Some complement components
- Products of neutrophil activity
How do neutrophils move
along a concentration gradient
What does the spread of acute inflammation suggest following injury?
chemical substances released from the injured tissues spread outwards into uninjured areas
What do these endogenous chemical mediators cause?
Vasodilation Emigration of neutrophils Chemotaxis Increased vascular permeability Itching and pain
What are the four enzymatic cascade systems that plasma contains
- The complement system
- the kinins
- the coagulation factors
- The fibrinolytic system
What do neutrophils do?
- Kill organisms
- degrade nectrotic tissue
- ingest offending agents
- produce chemical mediators, toxic oxygen radicals and enzymes
How do neutrophils achieve this?
Movement (chemotaxis
recognition pf and adhesion to micro-organisms
phagocytosis
intracellular killing micro-organisms
What causes microorganisms to be recognised
not recognised until being coated in opsonins
What are opsonins
these bind to specific receptors on leucocytes and greatly enhance phagocytosis
Name some major opsonins
Fc Fragment of IgE
Collectins - plasma proteins that bind to cell walls
Define phagocytosis
The process whereby cells such as neutrophils and macrophages ingest solid particles
