Healing And Repair Flashcards
What kind of populations can be replaced if lost
Only labile and stable cells
What are labile cells
Multiply continually throughout life
GI tract bone marrow
What are stable cells
Only multiply when recieve stimulus to do so
Hepatocytes
Endothelium
What are permanet cells
Cannot multiply
Neurones
Skeletal muscle
What is complete repair
Restitution Labile and stabile cell populations Must be replaced with scar tissue formation Tissue architecture must en preserved Hepatitis a
What is repair by connective tissue fibrosis
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
What does repair by connective tissue fibrosis involve
Angiogenesis - form new blood vessels
Migration and proliferation of fibroblasts
Deposition of collagen
Maturation and organisation of fibrous tissue remodelling
What is angiogenesis and what does it involve
Critical to chronic inflam and fibrosis
Tumour cell growth
Formation of collateral circulation.
What hallens in angiogenesis
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
What forms fibrovasc granulation tissue
Fibroblast migration and laying down of matrix forms fibrovasc gars nutation tissue
What triggers migration and prolif of fibroblasts
Multiple growth factors FGF PDGF
What are some sources of growth factors
Platelets
Inflam cells
Activated endothelium
As repair progresses fibroblasts lay down increasing amounts of
Collagen
What are the major types of collagen
1
2
3
4
What are the characteristics of collagen type 1
Bundles of banded fibres, high tensile strength
A lot in skin and bone
What are the characteristic of collagen type 2
Thin fibrils structural protein
Mostly in cartilage
What are the major characteristics of type 3 collagen
Thin fibrils pliable
Skin
What is the characteristic of type 4 collagen
Amorphous all base mems
How is granulation tissue formed to scar
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
What is the difference between scarring first intention and second intention
First - surgical scar - closely apposed edges minimal granulation tissue minimal fibrosis
Secondary - ulcerated surface - edges widely separated prominent granulation tissue prominent fibrosis
What happens to the wound strength
Increases with time but never full strength
What are local factors inducing wound healing
Infection
Mechanical factors
Foreign bodies
Size, location and type of wound
What are the systemic factors for wound healing
Nutrition
Metabolic status
Circulatory status
Hormones
What is the regenerative capacity like for neural tissue
No regn in neurones or cns
What kind of populations can cells be divided into
Labile, stabile, permanent
