Healing and Repair

Question 1

What is healing?

Answer 1

Physiological response to tissue response to tissue damage

Question 2

What are the two main causes of tissue damage?

Answer 2

• Wound

- Inflammatory process in internal organ

Question 3

What are the two steps to healing and repair?

Answer 3

• Regeneration

- Scar formation

Question 4

What is regeneration in healing?

Answer 4

Growth of cells and tissues to replace lost structures

Question 5

What is scar formation in healing?

Answer 5

Laying down of fibrous tissue

Question 6

What does the result of healing depend on? (4)

Answer 6

• Damage nature
• Damage severity
• Damage duration (acute/chronic)
• Tissue type involved

Question 7

What are the two types of cell renewal?

Answer 7

• Proliferation

- Differentiation

Question 8

What does proliferation do in cell renewal?

Answer 8

Replace lost cells

Question 9

What does differentiation do in cell renewal?

Answer 9

Replace complex architectural structures

Question 10

What are the 3 types of cell according to proliferation ability?

Answer 10

• Labile cells
• Stable cells
• Permanent cells

Question 11

What is the proliferation ability of labile cells?

Answer 11

Good capacity to proliferate

Question 12

What is the proliferation ability of stable cells?

Answer 12

Slow proliferative rate unless necessary, specific stimulus increases rate

Question 13

What is the proliferation ability of permenant cells?

Answer 13

No effective regeneration

Question 14

Give an example of a labile cell

Answer 14

Skin basal cell

Question 15

Why do skin basal cells have a high proliferation rate?

Answer 15

Increased mitotic activity, always building up to replace loss

Question 16

Give an example of a stable cell

Answer 16

Hepatocytes

Question 17

In what situation can stable cells regenerate quickly?

Answer 17

Post trauma

Question 18

What are the consequences of myocardium being permanent cells post MI?

Answer 18

• Old MI healed
• Not replaced with new myocardium just with fibrotic tissue
• No contractile ability
• Less resistant to mechanic pressure
• Can expand cause aneurysm after MI

Question 19

What can fibrotic plaques in the heart cause?

Answer 19

Arythmia - alters specific heart area contraction ability because can’t transmit stimulus

Question 20

What is liver cirrhosis made up of in terms of healing?

Answer 20

Fibrosis with proliferation and regeneration of hepatocytes

Question 21

What are the properties of the liver in liver cirrhosis? (6)

Answer 21

• Micronodularity
• V uneven surface
• Hard to touch
• Fibrosis between nodules
• Decreased in size
• Palpable

Question 22

What can be seen histologically in liver cirrhosis?

Answer 22

Regenerative nodule of hepatocytes surrounded by strands of fibrous tissue

Question 23

How does fibrosis affect labile and stable cell population?

Answer 23

Damage of both parenchymal and stromal cells

Question 24

What are parenchymal cells?

Answer 24

Functional cells of an organ in the body

Question 25

What are stromal cells?

Answer 25

Structural tissue of organs - connective tissues

Question 26

How does fibrosis affect the permanent cell population?

Answer 26

Damage to non regenerating cells

Question 27

What are the 3 parts to fibrosis?

Answer 27

• Formation of granulation tissue
• Extracellular matrix protein deposition
• Remodelling

Question 28

What is granulation tissue later replaced by in fibrosis?

Answer 28

Fibrous tissue

Question 29

What extracellular matrix proteins are deposited in fibrosis?

Answer 29

• Collagens

- Fibronectin

Question 30

What deposits extracellular matrix proteins in fibrosis?

Answer 30

Fibroblasts

Question 31

What occurs in remodelling in fibrosis?

Answer 31

Maturation and organisation of fibrous tissue