Topic 2: Healing and Chronic Inflammation

Question 1

What injury causes acute inflammation?

Question 2

What are the vascular changes and cellular recruitment in acute inflammation?

Question 3

What are the 3 kinds of mediators involved in acute inflammation? (provide examples and where they have an effect)

Question 4

What are the hallmark features of acute inflammation?

Question 5

How do cells recognise, engulf, kill and degredate foreign material?

Question 6

What are the potential outcomes of acute inflammation?

Answer 6

resolution (no tissue loss), regeneration or repair (tissue loss), chronic inflammation

Question 7

Recap the steps of acute inflammation.

Question 8

What is the most critical factor in the resolution of acute inflammation?

Answer 8

removal of the cause of injury

Question 9

Define healing

Answer 9

process by which the body replaces damaged tissue with living tissue

Question 10

What is regeneration in healing?

Answer 10

e.g. surgical inscision

Question 11

What is repair in healing?

Answer 11

e.g. extensive loss of tissues

Question 12

What is scaring in healing?

Answer 12

e.g. abscess

Question 13

What are the 4 factors in weather the tissue undergoes regeneration or repair?

Answer 13

• Replicative potential of tissue
  e.g. epithelial cells vs cardiac muscle
• extent of injury
• persistence of injurious agent
• location

Question 14

Compare the outcome of acute and chronic inflammation. (diagram)

Question 15

What is granulation tissue?

Answer 15

• the tissue of repair
• rough, granular, glistening, wet
• inflammatory cells (macrophages)
• new blood vessels
• fibroblasts
• collagen

Question 16

What are growth factors?

Answer 16

• macrophages are an important source to making these
• stimulate cellular processes including cell proliferation, migration, differentiation and multicellular morphogenesis during development and tissue healing

Question 17

What are important biological activities in developing granulation tissue?

Question 18

What local and systemic factors may impair healing?

Answer 18

• -

systemic
- age
- nutritional status (esp. protein)
- systemic diseases (diabetes, neoplasia, cancers)
- steroid treatment (corticosteroids)

Question 19

What is specialised healing? What are the 5 stages?

Answer 19

• in fractures and nerves

1. haematoma and inflammation
2. angiogenesis
3. proliferation of undifferentiated mesenchymal tissues (soft callus)
4. mineralisation via intramembranous or endochondral osteogenesis (hard callus –> woven bone)
5. remodelling –> lamerlla bone

different to the healing of soft tissue, you want to bone, not scar tissue.

Question 20

Define chronic inflammation

• duration
• cellular response
• process

Answer 20

Duration (when its more than 6 weeks)

Cellular response (mononuclear, not polymorphonuclear like neutrophils in acute inflammation)

Process (inflammation and healing happening at the same time)

Question 21

When might you have an acute inflammation without neutrophils?

Answer 21

• physical injury (no infection)
• viral infection (don’t have n-formyl peptides)

Question 22

When does healing happen in acute and chronic?

Answer 22

acute - after inflammation
chronic - concurrently

Question 23

what are the vascular changes in

Answer 23

acute - dialation and increase perm
chornic - angiogeneesis (formation of new blood vessels)

Question 24

what are 2 kinds of causes of chronic inflammation?

Answer 24

• acute irritant not eliminated
• prolonged exposure to low-intensity irritants (splinter, chronic infection)

Question 25

What is osteomyelitis?

Answer 25

• crater leading to a bone abscess on leg -> sinus formation
• persisting acute infection -> chronic inflammation

Question 26

Describe the histology of osteomyelitis.

Refer to acute and chronic inflammatory and healing regions and hallmarks.

Answer 26

• acute inflammatory zone: neutrophils, dilates and congested blood vessels, fibrinous exudate
• change in cellular process: macrophages, less exudate, less prominent blood vessels
• healing zone: fewer cells, granulation tissue, collagen

Question 27

What is the outcome of granulation tissue? how is this a problem in bone?

Answer 27

• loss of function and scar tissue. not as strong as bone!

Question 28

Why is the bacteria not properly cleared in bone?

Answer 28

• bacteria in bone increase the pressure, and bone can’t swell so the blood cells die from hypoxic injury reducing the ability to provide an effective response
• treatment could be amputation to try stop the spread

Question 29

What are the main 4 cells involved in chronic healing?

Answer 29

Macrophage
Lymphocytes
Granulocytes
Endothelial cells

Question 30

How are macrophages actived? What do they produce?

Answer 30

• classical activation
• alternative activation

Question 31

How are lymphocytes activated? What mediators do they produce?

Question 32

Describe the histology of chronic inflammation due to a foreign body: gout

Answer 32

• macrophages try to eliminate, but cannot
• epithelioid cells
• multinucleate giant cell
• gout uric acid crystals

Question 33

What is a granuloma?

Answer 33

• not grannulation tissues
• microscopoc lesion
• made up of lymphocytes, multinucleate giant cell, one more*

Question 34

What are the consequences of chronic inflammation?