Inflammation

Question 1

What is the cause of acute inflammation

Answer 1

Any form of tissue injury

Question 2

Give the three phases of tissue injury

Answer 2

Fluidic, Cellular, Reparative

Question 3

Give 4 signs of acute inflammation

Answer 3

Redness and heat (increased blood flow)
Swelling (fluid accumulation)
Pain (chemical release stimulates nerve endings)
Loss of function

Question 4

Describe the process of cellular and vascular response through acute inflammation

Answer 4

1. Momentary vasoconstriction - reflex process to reduce blood loss
2. Dilation of Blood vessels - Caused by release of chemical mediators
3. Exudation of fluid - Reduced blood flow, proteinaceous fluid released
4. Leukocyte migration - Adherence of circulatory WBCs to altered endothelium
5. Leukocyte emigration - Migrate into tissues via diapedesis
6. Temperature increase

Question 5

Define transudates and describe their appearance

Answer 5

Extracellular filtrate of plasma with a little protein and few/no nucleated cells
- Glossy, clear and watery appearance

Question 6

Describe how transudate is produced

Answer 6

Produced by fluid leakage due to increased hydrostatic pressure or reduced osmotic potential in the blood vessels

Question 7

Define exudates and describe its appearance

Answer 7

ECF that is protein rich and contains high numbers of cells

- Purulent, fibrinous, serous

Question 8

Describe how exudates are formed

Answer 8

Formed during inflammation due to increased vascular permeability

Question 9

Define effusion

Answer 9

Accumulation of fluid in a body space or cavity

Question 10

Describe the process by which pyrexia is produced

Answer 10

= Raised body temperature/fever

• Exogenous factors cause release of endogenous factors which in turn activate the arachidonic pathway and PGE2 release
• PGE 2 acts on the preoptic are of the hypothalamus through the EP3 receptor leading to the stimulation of the sympathetic output system which evokes non-shivering and shivering thermogenesis to produce body heat and skin vasoconstriction to decrease heat loss from the body surface

Question 11

Where do antipyretic drugs act on the pyrexia process?

Answer 11

Act at the hypothalamus, overriding the action of PGE2 in causing increased temperature

Question 12

Give three inflammatory mediators that cause vasodilation

Answer 12

Nitric Oxide
Bradykinin
Prostaglandins PGE2

Question 13

Give three inflammatory mediators that cause inceraced vascular permeabilities

Answer 13

Vasoconstrictive amines e.g. histamine
Complement factors e.g. C5a, C3a
Leukotrines

Question 14

Give three inflammatory mediators that cause chemotaxis and leukocyte activation

Answer 14

Leukotrines
C5a
Chemokines e.g. IL-8, IL-5

Question 15

Give two inflammatory mediators that cause tissue damage

Answer 15

Neutrophil granule content : matrix metalloproteinases

ROS

Question 16

Give two inflammatory mediators that cause Pain

Answer 16

Bradykinin

PGE2

Question 17

Give three inflammatory mediators that cause Fever

Answer 17

Cytokines e.g. IL-1 TNF, IL-6

Question 18

Describe Plasma derived chemical mediators

Answer 18

e. g. complement proteins, kinins

- Present in the plasma as precursors that must be activated

Question 19

Describe cell derived chemical mediators

Answer 19

e.g. histamine

Sequestered in intracellular granules that need to be secreted

Question 20

Describe acute phase proteins

Answer 20

• Inflammatory biomarkers
• Plasma protein synthesised by liver
• Increase in serum concentration over 25% in response to cytokines
• Causes fever and leucocytosis (part of the innate immune system)

Question 21

Describe the complement cascade

Answer 21

• Helps the innate immune system to clear pathogens from an organism
• Plasma complement C1-9 synthesized in the liver
• Are activated and induce inflammation and further activation of the immune system
• End result is cell killing membrane attack complex (MAC)

Question 22

Describe arachidonic acid metabolites

Answer 22

• Damage of the cell leads to the cell membrane lipids rearranging to create biologically active lipid mediators (derived from arachidonic acids)
• Effects are short lived due to rapid decay and enzymatic destruction of lipid metabolites

Question 23

Describe 4 causes of chronic infection

Answer 23

• Persistent infection
• Prolonged toxin exposure
• Indestructible foreign material
• Immune mediated disease

Question 24

Describe the morphology of chronic inflammation

Answer 24

• Tissue destruction
• Healing attempts
• Infiltration with mononuclear cells (macrophages, lymphocytes)

Question 25

Describe macrophage activity in chronic inflammation

Answer 25

Migration and Activation - extravasation controlled by ashesion molecules and chemical mediators with chemostatic activating properties. Activated Macrophage - Eliminate injurious agent - Instigate the healing process (fibrosis and angiogenesis) - Cause tissue injury (chronic) - Release products that are toxic to microorganisms

Question 26

Describe the involvement of lymphocytes in chronic inflammation

Answer 26

Interact bidirectionally by recruiting and being recruited by macrophages

Question 27

Describe the involvement of Plasma cells in chronic inflammation

Answer 27

Activated by B lymphocytes and produce antibodies against persistent foreign antigens

Question 28

Describe the involvement of eosinophils in chronic inflammation

Answer 28

Present in parasite and some fungal infections | Also hypersensitivity infection

Question 29

Describe the involvement of mast cells in chronic inflammation

Answer 29

Found in the connective tissue both in acute and chronic inflammation

Question 30

Describe the involvement of neutrophils in chronic inflammation

Answer 30

Characteristic in acute may be found in chronic e.g. abcesses

Question 31

Give the three phases of healing

Answer 31

Blood clot Proliferation and granulation Remodelling and maturation

Question 32

Describe an abcess

Answer 32

Collection of pus circumscribed by a fibrous capsule that is visible grossly (most commonly caused by bacteria)

Question 33

Describe pus

Answer 33

Plasma proteins, leukocyte based yellow/green liquid

Question 34

Describe a granuloma

Answer 34

Nodular aggregation of macrophages surrounded by a collar of mononuclear leucocytes Aims to contain agent that is difficult to eradicate against : parasite, fungi, bacteria, viruses, foreign body

Question 35

Define regeneration

Answer 35

Proliferation of cells and tissues to replace lost structures

Question 36

Define repair

Answer 36

Replacement of injured cells with connective tissue

Question 37

Describe the blood clot stage of healing

Answer 37

- Activation and coagulation - Blood clot formation - Neutrophils arrive

Question 38

Describe the Proliferation and granulation stage of healing

Answer 38

- Macrophages replace neutrophils (clean and promote proliferation) - Granulation tissue formed from proliferation of fibroblasts and endothelial cells - Fibroblasts and connective tissue grow parallel to the wound surface and perpendicular to proliferating capillaries

Question 39

Describe the remodelling and maturation phase of healing

Answer 39

Leukocytes and increased vascularity disappear after the second week Granulosa converted into a pale avascular scar (fibroblasts and dense collagen) Wound contraction