Repair and Regeneration

Question 1

what’s the two different types of inflammation?

Answer 1

acute and chronic

Question 2

what are the physiological changes to the cells after a repair?

Answer 2

scar formation
loss of function
cells cannot regrow

Question 3

what are the physiological changes to the cell after a regeneration?

Answer 3

cells can regrow

restoration of the normal structure and function

Question 4

what are the two most important factors in determining the outcome of injury?

Answer 4

the ability of the cells to replicate

the ability to rebuild complex architectural structures.

Question 5

what are the stages of the cell cycle?

Answer 5

G1,
S,
G2,
M,

Question 6

what are the characteristics of labile cell populations

Answer 6

High normal turnover
active stem cell population
excellent regenerative capacity

Question 7

give an example of a labile cell population?

Answer 7

epithelia

Question 8

what are the characteristics of stable cell populations?

Answer 8

low physiological turnover
turnover can massively increase if needed
good regenerative capacity

Question 9

what is another name for stable cell populations

Answer 9

Quiescent

Question 10

what is examples of quiescent cell populations?

Answer 10

liver, renal tubules

Question 11

what are the characteristics of permanent cell populations?

Answer 11

No physiological turnover
long life cells
no regenerative capacity

Question 12

give an example of a type of cells that have no regenerative capacity?

Answer 12

neurons

striated muscle cells

Question 13

what type of replication do stem cells undergo?

Answer 13

asymmetric replication

Question 14

where are stem cell pools present?

Answer 14

labile and stable cell populations

Question 15

why is the survival of stem cells important and how can the survival be threatened?

Answer 15

CRUCIAL to regeneration

its vulnerable to radiation injury

Question 16

what type of cell population are hepatocytes?

Answer 16

stable

Question 17

how is regeneration of cells controlled?

Answer 17

contact inhibition
growth factors
cell-cell and cell-matrix interactions

Question 18

explain the mechanism in which a minor skin abrasion that has is lost epidermis is regenerated?

Answer 18

cells at margins proliferate and spread out as a thin sheet across the dermis
once defect is covered, the stimulus for them to proliferate and mover is switched off via - contact inhibition.
Epidermis then grows from the base upwards

Question 19

what is organisation 1?

Answer 19

this is the repair of specialised tissue by formation of fibrous scar.

Question 20

what is produced in organisation 1?

Answer 20

granulation tissue produced on scaffold of fibrin

Question 21

what is organisation 2?

Answer 21

this where the granulation tissue contracts and accumulates collagen, forming a scar

Question 22

what is organisation a consequence of?

Answer 22

pneumonia a d infarction

Question 23

what is the constituents of granulation tissue

Answer 23

capillary loops
phagocytic cells 
- neutrophils 
-macrophages 
myofibroblasts

Question 24

why is wound contraction important?

Answer 24

important for reducing volume of tissue for repair - reduce by 80%

Question 25

what is healing by first intention?

Answer 25

this is a clean surgical wound which has been closed at the end of the procedure to maximise chance of healing

Question 26

what are the stages for healing by first intention

Answer 26

1. edges of the incision are joined by thin layer of fibrin. replaced by collagen covered by surface epidermis 2. coagulated blood forms a scab 3. epidermis grows over defect

Question 27

why is a keratin filled cyst formed?

Answer 27

if the wound is still gaping after epidermis grows over defect, epidermal cells can grown down into defect. these usually stop growing but can remain and form the cyst.

Question 28

what is a residual defect of healing by first intention?

Answer 28

inability to reconstruct the elastic network within the dermis

Question 29

what is the difference between healing by second intention and first intention

Answer 29

fundamentally not a different process. but the wound edges are not apposed. more extensive scarring

Question 30

what are some local factors that inhibit healing

Answer 30

``` infection haematoma blood supply foreign bodies mechanical stress ```

Question 31

what are some systemic factors inhibit healing

Answer 31

``` age drugs i.e. steroids anaemia diabetes malnutrition catabolic states vitamin c deficiency trace metal deficiency ```

Question 32

why does steroids inhibit healing?

Answer 32

it has immunosuppressive actions and therefore interfere with formation of granulation tissue

Question 33

why does vitamin D deficiency inhibit healing?

Answer 33

vit. C is involved in collagen synthesis. collagen main protein in the ECM.

Question 34

what is Keloid?

Answer 34

this is a dermal injury that sometimes followed by excessive fibroblast proliferation and collagen production. this is a genetically determined process

Question 35

what are the steps of fracture healing?

Answer 35

1. a haematoma is formed and organised. 2. removal of necrotic fragments 3. osteoblasts lay down disorganised woven bone 4. remodelling according to mechanical stress 5. replacement by more orderly lamellar bone

Question 36

where are EGF from?

Answer 36

platelets macrophages saliva plasma

Question 37

what is the function of EGF?

Answer 37

mitogenic for keratinocytes and fibroblasts stimulates granulation tissue formation

Question 38

where are TGF-B

Answer 38

``` platelets T Lymphocytes macrophages endothelial cells keratinocytes smooth muscle cells fibroblasts ```

Question 39

what is the function of the TGF-B?

Answer 39

chemotactic for PMNs, macrophages, lymphocytes, fibroblasts and smooth muscle cells stimulate TIMP synthesis angiogenesis and fibroplasia inhibits production MMPs and keratinocyte proliferation

Question 40

where is PDGF from?

Answer 40

platelets, macrophages, endothelial cells, keratinocytes and smooth muscle cells

Question 41

what is the function of the PDGF?

Answer 41

chemotactic for PMNs, macrophages, fibroblasts and smooth muscle cells activates PMNs, macrophages and fibroblasts mitogenic for fibroblasts, endothelial cells and smooth muscle cells stimulates production of MMPs, fibronectin and HA stimulates angiogenesis

Question 42

where is KGF from?

Answer 42

fibroblasts

Question 43

what is the function of KGF?

Answer 43

Stimulates keratinocytes migration, proliferation and differentation

Question 44

where is TNF from

Answer 44

macrophages, mast cells, T lymphocytes

Question 45

what is the function of TNF?

Answer 45

activates macrophages, regulates other cytokines

Question 46

where is the VEGF

Answer 46

many types of cells

Question 47

what is the function of VEGF?

Answer 47

increases vascular permeability mitogenic for endothelial cells