21 - Inflammation and Healing II - Outcomes, Mediators and Healing

Question 1

Mediators of acute inflammation
1)
2)
3)
4)
5)
6)
7)

Answer 1

1) Vasodilation
2) Increased vascular permeability
3) Endothelial activation
4) Chemotaxis
5) Tissue damage
6) Pain
7) Fever

Question 2

Mediators of vasodilation in acute inflammation

Answer 2

Histamine, nitric oxide, prostaglandin, etc.

Question 3

Mediators of increased vascular permeability in acute inflammation

Answer 3

Histamine, serotonin, bradykinins, leukotrienes

Question 4

Mediators of endothelial activation in acute inflammation

Answer 4

TNFa, IL-1

Question 5

Mediators of chemotaxis in acute inflammation

Answer 5

Complement fragments, bacterial fragments, IL-8, Leukotriene B4

Question 6

Mediators of pain in acute inflammation

Answer 6

Prostaglandins, bradykinin

Question 7

Mediators of fever in acute inflammation

Answer 7

IL-1, IL-6, TNFa, prostaglandins

Question 8

What is cyclooxygenase, and by extension prostaglandins, derived from?

Answer 8

Arachidonic acid

Question 9

Prostacyclin

Answer 9

Arachadonic acid derivative.
Produced by normal epithelial cells.
Vasodilator, inhibits platelet aggregation

Question 10

Outcomes of acute inflammation
1)
2)
3)
4)

Answer 10

1) Eradicate cause
2) Deal with exudate
3) Replace damaged cells (replenish or replace with scar tissue)
OR
4) Inflammation continues

Question 11

How is exudate from inflammation dealt with?

Answer 11

Macrophages take up debris, fluid drains into lymphatic system

Question 12

Three divisions of cells, based on replicative ability

Answer 12

1) Labile (constantly in cell cycle)
2) Stable or facultative dividers (can enter cell cycle if prompted)
3) Permanent (terminally differentiated)

Question 13

Location of stem cells in GIT

Answer 13

Crypts

Question 14

Healing involves migration and proliferation of which cells?

Answer 14

• Epithelium in epithelial tissues
• Fibroblasts, myofibroblasts and endothelial
cells which form scar tissue, generally via the
formation of granulation tissue

Question 15

Granulation tissue

Answer 15

Occurs in healing. Generates scar tissue

Question 16

Components of granulation tissue
1)
2)
3)
4)
5)

Answer 16

1) Macrophages and lymphocytes
2) New blood vessels
3) Migrating fibroblasts
4) Deposited ECM
5) Granulation tissue initially cellular and vascularised, later becomes mostly fibrous tissue (collagen = scar tissue)

Question 17

Vascularisation in granulation tissue 
1)
2)
3)
4)
5)

Answer 17

1) Degradation of basement membrane by matrix metalloproteinases (MMPs) and loss of
cell to cell contact between endothelial cells
2) Migration and proliferation of endothelial cells toward angiogenic stimulus
3) Maturation of cells, recruitment of pericytes and smooth muscle cells
4) New vessels are leaky
5) VEGF secreted by various mesenchymal cells important

Question 18

Name for healing of clean wounds with closely-opposed edges

Answer 18

Healing by primary intention

Question 19

Part of damaged tissue that can regrow

Answer 19

Epidermis can grow over the top of scar tissue

Question 20

Juxtacrine

Answer 20

Signalling between cells that are next to each other.

Often occurs when transmembrane proteins are between communicating cells

Question 21

Growth factors in repair
1)
2)
3)

Answer 21

1) Released by many cell types in inflammation (EG: immune cells, epithelial)
2) Activate c-MYC, c-JUN, p53 in target cells, often through tyrosine-kinase activity
3) Lead to proliferation of epithelium, endothelium, fibroblasts

Question 22

Example of a signal transduction pathway involved in healing that isn’t linked to a tyrosine-kinase receptor

Answer 22

JAK/STAT

Question 23

How does an abscess form?

Answer 23

Marked neutrophilic response leads to tissue destruction

Question 24

Why are abscesses hard to treat?

Answer 24

Bacteria are in middle of puss, neutrophils and antibiotics can’t reach this, as it isn’t vascularised.
If chronic, a fibrous capsule can form around it.

Question 25

Two types of healing possible

Answer 25

Resolution - Complete restoration of normal tissue, without scarring.
Healing by repair - Scar formation.

Question 26

Example of healing by resolution

Answer 26

Lobar pneumonia, if antibiotics are given quickly, as only epithelial cells are damaged, and these can regenerate

Question 27

Name for a wound coming open

Answer 27

Dehiscence