Session 2-Acute Inflammation Flashcards
What are the causes of acute inflammation? (5)
- microbial infections
- hypersensitivity reactions
- physical agents such as heat, light and radiation
- chemicals
- tissue necrosis
What are the clinical signs of acute inflammation? (5)
1) rubor=redness
2) tumor=swelling
3) calor=heat
4) dolor=pain
5) loss of function
Which changes occur in tissues in acute inflammation? (3)
1) changes in blood flow
2) exudation of fluid into tissues
3) infiltration of inflammatory cells
What are the steps of the vascular phase of acute inflammation? (3)
1) Transient vasoconstriction of arterioles
2) Vasodilation of arterioles and then capillaries (increased blood flow -> heat and redness)
3) Increased permeability of blood vessels
What is stasis?
Increased viscosity of blood
Which chemical mediator is responsible for the immediate early response?
Histamine
Which cells release histamine? (3)
Mast cells
Basophils
Platelets
What does the release of histamine cause? (3)
1) Vascular dilatation
2) Transient increase in vascular permeability
3) Pain
Histamine is released in response to which stimuli?
1) physical damage
2) immunologic reactions
3) Complement (C3a, C5a)
What determines fluid flow across vessel walls?
Balance of hydrostatic and colloid osmotic pressure
Complete the sentence:
Increased hydrostatic pressure leads to __________ fluid flow out of the vessel
Increased
Complete the sentence:
Increased colloid osmotic pressure of interstitium leads to __________ fluid flow out of vessel
Increased
Complete the sentences:
Arteriolar dilatation leads to ____________ hydrostatic pressure. Increased permeability of vessel walls leads to _______ of protein into interstitium therefore net flow of fluid out of cell leads to ___________.
Increased
Loss
Oedema
True or false: oedema can be transudate or exudate
TRUE
Define transudate
Oedema has the same protein content as plasma
Define exudate
Oedema has more protein than plasma
What does oedema lead to?
Increased lymphatic drainage
What is fluid loss in inflammation called?
Exudate (high protein content)
Fluid loss due to hydrostatic pressure imbalance is called what?
Transudate
What are the mechanisms of vascular leakage? (5)
1) endothelial contraction (gaps)
2) cytoskeletal reorganisation (gaps)
3) direct injury - toxic burns, chemicals
4) leukocyte dependent injury
5) increased transcytosis
What is transcytosis?
Fluid moves across wall of non-leaky blood vessel
Which plasma protein is good at localising inflammation?
Fibrin
Which is the primary type of WBC involved in inflammation?
Neutrophil
What is another name for neutrophil?
Polymorph
What are the steps of neutrophil infiltration? (4)
1) Margination
2) Rolling
3) Adhesion
4) Emigration
Describe the first step of neutrophil infiltration
Margination-stasis causes neutrophils to line up at the edge of blood vessels along the endothelium
Describe the second step of neutrophil infiltration
Rolling-Neutrophils roll along the endothelium, sticking to it
Describe the third step of neutrophil infiltration
Adhesion-Neutrophils stick avidly to the endothelium
Describe the fourth step of neutrophil infiltration
Emigration-neutrophils emigrate through blood vessel wall
How do neutrophils escape from vessels? (3)
1) Relaxation of inter-endothelial cell junctions
2) Digestion of vascular basement membrane
3) Movement
What is chemotaxis?
Movement along concentration gradients of chemoattractants
What are the three simple steps of phagocytosis?
1) contact
2) recognition
3) internalisation
What happens in opsonisation?
Substances are coated by immunoglobulins or complement to make them recognisable by neutrophils
Give an example of an opsonin
C3b
What do phagosomes fuse with?
Lysosomes, to produce secondary lysosomes
What are the two killing mechanisms?
1) oxygen dependent
2) oxygen independent
What is produced in the oxygen dependent killing mechanism?
Produces superoxide and hydrogen peroxide
Which killing mechanism is more effective?
Oxygen dependent
How do neutrophils migrate to a site of injury?
Chemotaxis
Why are neutrophils not 100% reliable?
Activated neutrophils may release toxic metabolites and enzymes, causing damage to host tissue
What are the three main classes of chemical mediators in acute inflammation?
1) proteases
2) prostaglandins/leukotrienes
3) cytokines/chemokines
Give examples of proteases (chemical meditators in acute inflammation)
Kinins
Complement system (C3a, C5a)
Coagulation system
True or false: cytokines are small proteins and chemokines are large proteins
FALSE - other way round
Which chemical mediators are responsible for increased blood flow in acute inflammation?
Histamine
Prostaglandins
Which chemical mediators are responsible for vascular permeability in acute inflammation?
Histamine
Leukotrienes
Which chemical mediators are responsible for neutrophil chemotaxis in acute inflammation?
C5a
LTB4
Bacterial peptides
Which chemical mediator is responsible for phagocytosis in acute inflammation?
C3b
How does exudation of fluid combat injury? (3)
1) delivers plasma proteins to area of injury
2) dilutes toxins
3) increases lymphatic drainage
How does infiltration of cells combat injury?
Removes phagocytic organisms (mostly polymorphs but also macrophages) and necrotic debris
How does vasodilation combat injury?
Increases delivery
Increases temperature
How does pain and loss of function combat injury?
Enforces rest
Reduces chance of further traumatic damage
True or false: acute inflammation can be local or systemic
TRUE
What are the local complications of acute inflammation? (4)
1) swelling-blockage of tubes
2) exudate-compression (eg cardiac tamponade), serositis
3) loss of fluid eg burns
4) pain and loss of function
What are the systemic effects of acute inflammation? (3)
1) fever
2) leukocytosis
3) acute phase response-decreased appetite, raised pulse, altered sleep patterns
The acute phase response leads to changes in plasma concentrations of what?
Acute phase proteins:
- CRP
- alpha-1 antitrypsin
- fibrinogen
Define shock
Clinical syndrome of systemic circulatory failure
What may happen after the development of acute inflammation? (4)
1) complete resolution
2) continued acute inflammation with chronic inflammation=abscess
3) chronic inflammation and fibrous repair
4) death
True or false: all mediators of acute inflammation have long half-lives
FALSE - have short half-lives
Give an example of a chemical mediator which is unstable and can break down by itself?
Prostaglandins
What can acute inflammation in the meninges cause?
Vascular thrombosis and reduced cerebral perfusion
What are the symptoms of lobar pneumonia?
Worsening fever Prostration Hypoxaemia Dry cough Breathlessness
Name some examples of causes of skin blisters
Heat
Sunlight
Chemical
What are the predominant features of skin blisters?
Pain
Profuse exudate
What type of necrosis occurs at the centre of an abscess?
Liquefactive
True or false: abscesses can cause high pressure and therefore lots of pain
TRUE (sadly)
What happens in acute inflammation in serous cavities?
Exudate pours into cavity
What is ascites?
Oedema in peritoneal cavity
What is the inflammation in pericarditis described as?
Bread and butter pericarditis
Give some examples of disorders of acute inflammation
Alpha-1 antitrypsin deficiency
Inherited Complement deficiencies
Defects in neutrophil function and numbers