Healing And Repair

Question 1

What kind of populations can be replaced if lost

Answer 1

Only labile and stable cells

Question 2

What are labile cells

Answer 2

Multiply continually throughout life

GI tract bone marrow

Question 3

What are stable cells

Answer 3

Only multiply when recieve stimulus to do so
Hepatocytes
Endothelium

Question 4

What are permanet cells

Answer 4

Cannot multiply
Neurones
Skeletal muscle

Question 5

What is complete repair

Answer 5

Restitution 
Labile and stabile cell populations 
Must be replaced with scar tissue formation 
Tissue architecture must en preserved 
Hepatitis a

Question 6

What is repair by connective tissue fibrosis

Answer 6

Tissue deconstruction includes loss of parenchymal cells and associated stromal framework
No regenerated parenchymal cells replaced by connective tissue (granulation tissue) which in time produces fibrosis and scarring

Question 7

What does repair by connective tissue fibrosis involve

Answer 7

Angiogenesis - form new blood vessels
Migration and proliferation of fibroblasts
Deposition of collagen
Maturation and organisation of fibrous tissue remodelling

Question 8

What is angiogenesis and what does it involve

Answer 8

Critical to chronic inflam and fibrosis
Tumour cell growth
Formation of collateral circulation.

Question 9

What hallens in angiogenesis

Answer 9

Degradation of basement mem of the parent vessel
Migration of endothelial cells toward angiogenic stimulus
Prolif of endothelial cells
Maturation of endothelial cells - central growth inhibition with remodelling into tubes
Recruitment of supporting cells - vasc smooth muscle cells

Question 10

What forms fibrovasc granulation tissue

Answer 10

Fibroblast migration and laying down of matrix forms fibrovasc gars nutation tissue

Question 11

What triggers migration and prolif of fibroblasts

Answer 11

Multiple growth factors FGF PDGF

Question 12

What are some sources of growth factors

Answer 12

Platelets
Inflam cells
Activated endothelium

Question 13

As repair progresses fibroblasts lay down increasing amounts of

Answer 13

Collagen

Question 14

What are the major types of collagen

Answer 14

1
2
3
4

Question 15

What are the characteristics of collagen type 1

Answer 15

Bundles of banded fibres, high tensile strength

A lot in skin and bone

Question 16

What are the characteristic of collagen type 2

Answer 16

Thin fibrils structural protein

Mostly in cartilage

Question 17

What are the major characteristics of type 3 collagen

Answer 17

Thin fibrils pliable

Skin

Question 18

What is the characteristic of type 4 collagen

Answer 18

Amorphous all base mems

Question 19

How is granulation tissue formed to scar

Answer 19

Newly formed capillaries regress so few vasc channels remain
Spaces between vasc channels become progressively filled by fibroblasts
Fibroblast align themselves to lay down collagen in a mainly uniform pattern
Collagen orientation slows for max strength in face of physical stresses

Question 20

What is the difference between scarring first intention and second intention

Answer 20

First - surgical scar - closely apposed edges minimal granulation tissue minimal fibrosis

Secondary - ulcerated surface - edges widely separated prominent granulation tissue prominent fibrosis

Question 21

What happens to the wound strength

Answer 21

Increases with time but never full strength

Question 22

What are local factors inducing wound healing

Answer 22

Infection
Mechanical factors
Foreign bodies
Size, location and type of wound

Question 23

What are the systemic factors for wound healing

Answer 23

Nutrition
Metabolic status
Circulatory status
Hormones

Question 24

What is the regenerative capacity like for neural tissue

Answer 24

No regn in neurones or cns

Question 25

What kind of populations can cells be divided into

Answer 25

Labile, stabile, permanent