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
Name me the symptoms of inflammation
serous = proteins rich exudate catarrhal = mucus hyper secretion fibrinous = exudate contains lots of fibrin haemorrhagic = severe vascular injury suppurative = production of pus membranous = epithelium is coated by fibrin pseudomembranous = superficial mucosal slough
What is caused by a fibrous clot
Herpes ulceration
Tell me more about suppuration
Causative stimulus virtually always infective agent
A collection of pus surrounded by a membrane of sprouting capillaries , neutrophils and occasional fibroblasts is called an abscess
What happens when a suppuration is drained
the abcess cavity collapses and is obliterated by organisation and fibroisis
Deep seated abscesses may drain along side a sinus tract or fistula
Whats ulceration caused by
Sloughing of inflammatory necrotic tissue
What are the most common types of ulceration
the mucosa - mouth, stomach, intestine
Chronic leg ulcers in those with circulatory disturbance
What are the benefits of Acute inflammation
- dilution of toxins as carried away by lymphatics
- entry of antibodies - due to increased vascular permeability
- fibrin formation - impedes movement of microorganisms
- transport of drugs- e.g. antibiotics
- delivery of nutrients and o2 - aided by increased fluid flow
- stimulation of the immune system as fluid exudate contains antigens which reach local lymph nodes
Disadvantages of acute inflammation
Digestion of normal tissues
Swelling - laryngeal oedema, Brian swelling
Inappropriate hypersensitive inflammatory response
What is pyrexia
A fever
Elevation in temperature of even a few degrees may improve the efficiency of leukocyte killing and probably impairs the replication of many offending microorganisms
What are the systematic effects of acute inflammation
Constitutional symptoms include:
- malaise (feeling of discomfort)
- anorexia
- nausea
weight loss due to negative nitrogen balance
reactive hyperplasia (increase in size of an organ) of the reticuloendothelial system (immune cell system)
Haemotological changes
Increased erythrocyte sedimentation rate Anaemia
Leukocytosis
