8 - Repair and regeneration Flashcards Preview

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Flashcards in 8 - Repair and regeneration Deck (16):
1

Difference between regeneration and repair

Regen = tissues return to normal
Repair = dmged cells cannot be replaced by like cells - hence fibrosis and scarring; loses specialised function

2

What is a labile cell population?

High normal turnover
Active stem cell population
Excellent regen capacity
e.g. epithelia

3

Stable cell population

Low physiological turnover
Turnover can massively increase if needed
Good regen capacity
e.g. liver, renal tubules

4

Permanent cell population

No physiological turnover
Long life cells
No regen capacity - as so specialised
e.g. neurons, muscle cells

5

why can a cirrhotic liver not repopulate its normal cells?

Long term damage causes collapse of reticulin (connective tissue framework). Leeds to formation of regen nodules divided by fibrous septa.

6

Compartments for stem cells

A stem cell can be stored in a stem cell compartment of progress through:
Amplifying cell compartment -> differentiating compartment -> terminal differentiation

7

What can destroy stem cells

Full thickness burn + radiation

8

What is granulation tissue?

Tissue with new capillary loops + phagocytic cells + (myo)fibroblasts

9

Skin wound healing in general

First by: primary intention
Second: secondary intention

10

What is healing by first intention?

Clean, uninfected surgical wound with good haemostasis
The edges are apposed with sutures or staples.

Gets small fibrous union

11

What is healing by second intention?

Wound edges not apposed
Not a fundamentally different process
More florid granulation tissue rxn
More extensive scarring

12

Why would wound edges not apposed?

Extensive loss of tissue
Apposition not physically possible
Large haematoma
Infection
Foreign body

13

When would you take sutures out?

Roughly 7 days after

14

How do fractures heal?

Haematoma is organised
Removal of necrotic fragments
Osteoblasts lay down woven bone (=callus)
Remodelling according to mechanical stress
Lamellar bones replace woven

15

What does non-union of a fracture look like?

Misalignment
Movement
Infection
Interposed soft tissue

16

Healing in the brain

Neurons are terminally differentiated.
Supporting tissue in glial cells rather than collagen and fibroblasts etc
Damaged tissue is removed leaving a cyst
Gliosis rather than scarring