Acute Inflammation 1

Question 1

What is acute inflammation?

Answer 1

o Acute inflammation is a fundamental response maintaining integrity of an organism.
o It is a series or protective changes occurring in living tissue as a response to injury.
o It is a dynamic homeostatic response found in higher organisms.

Question 2

What micro-organisms can cause acute inflammation?

Answer 2

• bacteria
• fungi
• viruses
• parasites

Question 3

What are the mechanical causes of acute inflammation?

Answer 3

• trauma
• all injuries even sterile
• surgery

Question 4

What are the chemical causes of acute inflammation?

Answer 4

• upset to pH

- irritation when bile and urine is in inappropriate place

Question 5

What are the physical- extreme condition causes of acute inflammation?

Answer 5

• heat=sunburn
• cold=frostbite
• ionising radiation

Question 6

Why does dead tissue cause acute inflammation?

Answer 6

cell necrosis irritates adjacent tissue

Question 7

What are the cardinal signs of inflammation?

Answer 7

• tumour
• dolor
• rubor
• calor
• loss of function

Question 8

What is the process of acute inflammation?

Answer 8

o Series of microscopic events
o Localised to affected tissue
o Take place in the microcirculation
o Result in the clinical symptoms and signs of acute inflammation- the cardinal signs.

Question 9

What is involved in microcirculation?

Answer 9

• capillary beds fed by arterioles and drained by venules
• extracellular space and fluid and fluid and molecules within it
• lymphatic channels and drainage

Question 10

What do starling forces control?

Answer 10

flow (fluid flux) across membrane

Question 11

What is involved in dynamic balance?

Answer 11

hydrostatic and colloid pressures, compartments and physical constants

Question 12

What is pathogenesis in acute inflammation?

Answer 12

o Changes in vessel radius- flow
o Change in the permeability of the vessel wall- exudation
o Movement of neutrophils from the vessel to the extravascular space.

Question 13

What are the 3 stages in the triple response?

Answer 13

flush, flare and wheal

Question 14

Describe the process of the triple response.

Answer 14

o Transient arteriolar constriction (few movements, probably protective)
o Local arteriolar dilatation (active hyperaemia)
o Relaxation of vessel smooth muscle (autonomic NS or mediator derived?)

Question 15

Why is there an increase in blood flow?

Answer 15

o Poiseuille’s law= flow is proportional to radius to the power of 4
o Increased arteriolar radius causes increased local tissue blood flow
o Results in observed redness and heat
o A minute increase in the radius of a vessel will majorly increase the flow if no other factor changes.

Question 16

Why is there increased permeability of blood vessels?

Answer 16

o It is a localised vascular response that takes place at the microvascular bed.
o There is endothelial leakage, the fluid and proteins are not held in the vessel lumen which causes an imbalance in starling forces.
o Locally produced chemical mediators are involved.

Question 17

What are the effects of increased permeability?

Answer 17

• Overall there is a net movement of plasma from the capillaries to the extravascular space.
• The process is known as exudation and the fluid leaked is exudate.
• Exudate is a fluid rich in protein, plasma and includes immunoglobulin and fibrinogen
• Fluid loss increases the viscosity which in turn slow rate of flow causing a change in flow characteristic in the vessel

Question 18

What are the effects of exudation?

Answer 18

• oedema is formed (accumulation of fluid in the extravascular space)
• cause of swelling of tissue
• the swelling causes pain and reduces function

Question 19

What is normal laminar flow?

Answer 19

• WBC, neutrophils at centre of vessel
• Surrounded by erythrocytes
• Plasma at edge of vessel

Question 20

What is flow in inflammation?

Answer 20

• loss of normal laminar flow
• red cells aggregate in the centre of the lumen- rouleaux formation
• neutrophils are found near endothelium- margination

Question 21

What are the phases of emigration of neutrophils?

Answer 21

• margination= neutrophils move to endothelial aspect of lumen
• pavementing= neutrophils adhere to endothelium
• emigration- neutrophils squeeze between endothelial cells. Active process to extravascular tissues

Question 22

What are some examples of acute inflammation?

Answer 22

• gingivitis
• pleural inflammation
• inflamed appendix
• acute pyelonephritis
• bacterial endocarditis

Question 23

What is the ideal outcome of acute inflammation?

Answer 23

• inciting agent isolated and destroyed
• macrophages move in from blood and phagocytose debris; the leave
• epithelial surfaces regenerate
• inflammatory exudate filters away
• vascular changes return to normal
• inflammation resolves

Question 24

What are the benefits of acute inflammation?

Answer 24

• rapid response to non-specific insult
• transient protection of inflamed area (cardinal signs)
• neutrophils destroy organisms and denature antigen for macrophages
• plasma proteins localise process
• resolution and return to normal

Question 25

What are the outcomes of acute inflammation?

Answer 25

- resolution - suppuration - organisation - chronic inflammation