wound healing and repair

Question 1

What happens after tissue injury

Answer 1

replacement of damaged components > regenration > restoration of normal function

CT replaces damaged components > repair by connective tissue > scar formation > either normal function of fibrosis

Question 2

Regeneration can only occur how

Answer 2

tissues composed of cells with proliferative capacity

Underlying structure of the tissue has not been too severley damaged

Question 3

Repair by scar formation can occur how

Answer 3

Toissue composed of cells with limited or no proliferative capacity OR underlying structure of tissue is lost

Question 4

The cell cycle is regulated by what?

Answer 4

cyclins

Question 5

What is the G0 phase?

Answer 5

Inactive cells, unfavourable condiitons, terminally differentiated cell

Question 6

Labile cells are?

Answer 6

Cells that constantly divide. lost and replaced, do not enter G0 phase

Question 7

Stable tissues are?

Answer 7

Quiescent
Enter G0
Re enter cell cycle if stimulated by loss of cells, limited capacity to regenerate

Question 8

Permanent tissues are?

Answer 8

Terminally differentiated, enter G0, cannot reenter the cell cycle. Limited stem cell replication (not sufficient for regeneration). Neurons, cardiac muscle cells

Question 9

Angiogensis is

Answer 9

new blood vessels

Question 10

what are the 3 triggers of cell proliferation

Answer 10

Growth factors, hormones, cytokines

Question 11

organs are made of what cells and what is the stroma?

Answer 11

parenchyma cells

Stroma is the supporting CT including theECM

Question 12

ECM

1) What proteins?
2) what are these proteins made of?
3) what type of gel is in the ECM
4) what molecules that initiate signalling and stuff?

Answer 12

1) fibrous structural proteins and adhesive glycoproteins
2) collagen and elastin for tensile strength
3) water hydrated gels known as proteoglycans. Compressive resistance and lubrication
4) cell adhesion molecules that initiate signalingcascades affecting locomostion, proliferation and differentiation

Question 13

What are the forms of ECM?

Answer 13

Basement membrane and interstitial matrix

Question 14

what is in the basememnt membrane?

Answer 14

Collagen, laminin and proteglycan

Question 15

what is in the interstitial matrix

Answer 15

Fibrillar collagens
elastin
proteoglycan and gyaluronan

Question 16

Stable cells are

1) located where?
2) limited capacity for what?
3) what organs?

Answer 16

1) parenchymal organs such as lunk kidney
2) limited capcity for regen
3) pancreas, adrenal, thyroid and lung

Question 17

main difference between regeneration and scarring?

Answer 17

Regeneration wil have an intact matrix whilst scarring will have a disrupted matrix.

Question 18

How does repair by connective tissue take place?

Answer 18

coagulative necrosis following M1

Question 19

Difference between granulation tissue and scar?

Answer 19

Granulation tissue

• proliferating fibroblasts
• Loose ecm
• new capillaries

Scar
- Accumulation of connective tissue

Question 20

Tissue repair by connective tissue involves what 4 steps

Answer 20

Formation of new blood vessels
Migration/proliferation of fibroblasts
Deposition of ECM (scarring)
Maturation and reorganisation of the fibrous tissue (Remodelling)

Question 21

Macrophages produce wha

Answer 21

growth factors andcytokines that stimulate repair

Question 22

M1 classical actvation

• activated by what?
• results inwhat

Answer 22

• activated by microbial products and IFN-Y

- Results in inflammation and microbicidial actions such as phagocytosis

Question 23

M2 alternative activation

• activated by what?
• Results in what?

Answer 23

• activated by IL13 and IL4

- results in tissue repair, anti inflamm effects

Question 24

Angiogensis known as what?

• how does it happen
• what does it provide?

Answer 24

Neovascularisation

• capillary sprouts from existing blood vessels
• provide collateral circulation at the site of injury

Question 25

What is edema

Answer 25

new leaky bloody vessels

Question 26

Recruitement and proliferation of fibrolasts occur when and how?

Answer 26

stimulated by growth factors and macrophages.

Repair begin when macrophages predominate at the site of injury following acute inflammation

Question 27

Scar formation

Granulation tissue leads to what and what is the change that occurs?

Answer 27

scarring

changes in the composition of the ECM. Balance between collagen synthesis and degradation.

Question 28

What is critical to the strength of the wound

Answer 28

Collagen synthesis, initial collagen type 3 is replaced by type 1.