Chronic Inflammation

Question 1

How does chronic inflammation occur?

Answer 1

can follow on from an unresolved acute inflammation or be chronic from the outset

Question 2

Which cells are primarily affected/ involved in chronic inflammation?

Answer 2

lymphocytes, plasma cells, macrophages, fibroblasts, vascular endothelium

Question 3

Presence of plasma cells in a tissue indicates what?

Answer 3

the body is producing an immune response against an antigen

Question 4

Where are macrophages derived from in chronic inflammation?

Answer 4

derived from circulating monocytes which leave the blood vessels and enter tissue

Question 5

Where are plasma cells derived from in chronic inflammation?

Answer 5

from B lymphocytes in the area of tissue damage

Question 6

What role do macrophages have in chronic inflammation? (3)

Answer 6

phagocytosis
antigen presentation
stimulation of fibroplasia & fibrosis

Question 7

Why do macrophages sometimes accumulate in tissues? (2 reasons)

Answer 7

• unable to lyse irritant/ foreign material
• some infectious agents survive in the macrophages e.g. acid fast bacilli

Question 8

What are the two variants of macrophages found in cases of chronic inflammation?

Answer 8

epithelioid cells- mainly secretory rather than phagocytic
giant cells- formed by fusion of macrophages or epithelioid cells

Question 9

What is Granulomatous inflammation?

Answer 9

type of chronic inflammation caused by organisms of low virulence but great persistence in the tissues

Question 10

Briefly describe the structure of a granuloma?
(3- core, surrounded, outer)

Answer 10

central core contains agent/irritant
core is surrounded by macrophages, lymphocytes & plasma cells (and eosinophils in parasitic granulomas)
outer fibrous capsule

Question 11

Briefly describe the process/ steps of tissue repair?

Answer 11

1. Removal of necrotic debris
2. Ingrowth of immature blood vessels (granulation tissues)
3. Production of immature scar tissue (known as fibroplasia)
4. Production of mature scar tissue (fibrosis)

Question 12

Where are fibroblasts derived from and what is their role?

Answer 12

derived from connective tissue cells and involved in the organisation of damaged tissue

Question 13

What role does endothelium play in tissue repair?

Answer 13

it proliferates from vascular endothelium into granulation tissue (immature blood vessels which will form a scar)

Question 14

What are the main features of granulation tissue? (3)

Answer 14

• Resistant to infection
• Forms scaffold that supports migration of epithelium
• Its contraction reduces the amount of tissue to be replaced

Question 15

What is Fibrosis?

Answer 15

When granulation tissue is replaced by mature fibrous tissue- the mature fibrous scar is as strong or stronger than the original tissue

Question 16

What factors can affect healing? (4)

Answer 16

species
age
nature of tissue damage (highly specialised tissue rarely repairs successfully)
extent of tissue damage

Question 17

What is the difference between regeneration & repair?

Answer 17

regeneration- replacement of damaged tissue by normal tissue - functional status is restored
repair- replacement of damaged tissue by fibrous scar tissue- scar tissue does not retain functional characteristics of the tissue it has replaced

Question 18

[tissues are divided into three categories according to their ability to regenerate normal structure]- Name the three tissues.

Answer 18

1. labile tissues
2. stable tissues
3. permanent tissues

Question 19

What are labile tissues? Give an example.

Answer 19

constantly replenish its tissue cells throughout life e.g. bone marrow, fat

Question 20

What are stable tissues? Give an example.

Answer 20

tissues that are able to regenerate in response to damage e.g. liver
or can respond to increased demand on its function e.g. skeletal & smooth muscle

Question 21

What are permanent tissues? Give an example.

Answer 21

tissues with poor or no regenerative capacity (usually highly specialised tissues) e.g., neuronal cell bodies, axons in the PNS, cardiac muscle myofibres

Question 22

Briefly summarise the stages of skin wound healing (4)
Include the role of fibrin & macrophages.

Answer 22

1. Haemostasis- Blood escapes from damaged blood vessels, platelet degranulation & fibrin clot binds to the edges and to form a scab
2. Inflammation- Cells produce enzymes which degrade the clot & remove debris- Macrophages promote repair. Fibrin & fibronectin provides stability and framework
3. Repair - Epithelial cells regenerate and bridge the gap
4. Consolidation/ Reconstruction