healing and repair Flashcards
—– is the replacement of destroyed or lost tissue by viable tissue
healing
1.the initial response of a damaged tissue is —-
2. other tissue responses to injury :
1.acute inflammation
2. resolution , regeneration , repair by fibrosis
-no tissue destruction
-damaging agent and cell debris are removed
- tissue returned to its pre injury state as: mild heat injury
are all under —-
resolution
—- the replacement of list tissue by the tissue of the same type
—- the replacement of the destroyed tissue by a fibrous scar
- regeneration
- repair
factors affecting the healing process :
- The ability to remove the causative agent
- The ability to clear the inflammatory debris
- The degree of architectural damage
- The ability of cell to proliferate
- The extent of extra-cellular matrix damage
tissue proliferative activity includes 3 types of cells which are:
- labile cells
- stable cells
- permanent cells
—– are cells that continuously divide and are derived from stem cells
labile cells as:
Epidermis, mucosal epithelium, GI tract epithelium
labile cells are —- healed by —– if the supporting storma is —–
- easily
- regeneration
- intact
—- are cells that have low levels of replication and can be stimulated to divide and they are healed by regeneration if the supportive storm and regenerative stem cells are intact
stable cells
Hepatocytes, renal tubular epithelium, pancreatic acini are —- cells
stable cells
—– are non dividing cells and replaced by connective tissue
permentant cells
Neurons, cardiac myocytes, skeletal muscle are —– cells
permanent cells
true or false:
-permanent cells have no regeneration
- polypeptide growth factors are the most important affecting cell growth
true , true
polypeptide growth factors are present in —- or produced —-
-Exert pleiotropic effects; proliferation, cell migration,
differentiation, tissue remodeling
-Regulate growth of cells by controlling expression of
genes that regulate cell proliferation
- serum or locally
the storm includes:
- extracellular matrix w” interstitial matrix and basement membranes
- mesenchymal cells
- vessels
its not just a scaffold for cells to grow on , it regulates cell growth , motility m and differentiation
this is ——
extracellular matrix which consists of:
▪ Fibrous structural proteins
▪ Collagens
▪ Elastin
▪ Adhesive glycoproteins that link ECM component
to one another and to cells
▪ Proteoglycans
the cell-cell interactions include:
- growth factors as: EGF, PDGF, FGF, VEGF, TGFβ
- cytokines
- growth inhibitors
cell matrix interactions include
- Integrins
▪ Cell surface receptors that mediate cellular attachment
to the extracellular matrix
▪ Transduction of signals from ECM to cells
the replacement of lost cells by cells of the same type through cell division by which the supporting framework is intact is known as —-
regeneration
the regeneration process is controlled by —- and — factors and interactions between —- and —-
- controlled by inhibitory and stimulatory factors
- cells and extracellular matrix
healing by fibrosis is healing by —- tissue and it occurs when :
- destruction of —–
- the death of —-
- organisation of —-
- connective tissue
- parenchymal cells and stromal framework
- permanent tissue
- inflammation
repair by connective tissue involves the production of —- tissue
1. involves angiogenesis - new vessels budding from old
2. fibrosis - consisting of emigration and proliferation of fibroblast and disposition of ECM type iii collagen
3. scar remodelling type iii collagen replaced by type I collagen ( collagenase - requires zinc )
- granulation tissue ( which is fibroblast + capillary buds and myofibroblast )
wound healing phases are:
1* Inflammatory phase
2* Proliferative phase
▪ Epidermal re-growth
▪ Dermal repair
3* Remodelling phase
▪ Restoration of elasticity
—- phase is the induction of acute inflammatory response by an initial injury which involves :
- inflammatory phase
- heamtoma formation , infiltration by neutrophils and infiltration by macrophages
the proliferative phase refers to:
—- proliferation
- formation of—-
-
-
- epithelial cells proliferation
- formation of new vessels
- granulation tissue
- proliferation of fibroblast ( sythesis of ecm proteins )
the replacement of granulation tissue by fibrous tissue is —- phase
remodelling phase which involves :
1- remodelling of parenchymal elements to restore tissue function
2- remodelling of connective tissue to achieve wound strength
3- degradation of excessive extracellular matrix ( metalloproteinase )
the types of wound healing are:
- primary intention
- secondary intention
stages of wound healing by primary intention :
day 1:
- wound is filled w —-
- —- surrounding tissue
- proliferation of —–
day 2:
- —-
- —- covers the surface
day 3:
- —– formation
day 5:
—- deposition
day 7:
—- removed
- blood clot
- acute inflammation
- epithelial cells
- macrophages
- epithelial cells
- granulation tissue
- collagen
- sutured
wound strength :
after suture are removed at – week , wound strenghth is only — of unwounded skin ( walkers law )
- by 3-4 months the wound strength is about —- of the unwounded skin ( walkers law)
- one week
- 10%
- 80%
wound healing secondary intention:
1. the process is similar to healing by —-
2. the edges are —- and — fills the gaps
3. is it slow/fast ?
4. the inflammatory reaction is more —-
5. wound —-
6. more —
- primary intention
- not approximate
- granulation tissue
- slower
- more intense
- contraction ( myofibroblast )
- more scarring
pathologic aspect of wound healing:
1. dififcent scar formation as:
2. excessive scar formation as:
3. contracture defromity
4. —— transformation which are extremely —
- wound rupture
- keloid type iii collagen and genetic predisposition
- malignant
- extremely rare
mucosal surfaces :
erosions are healed by —
ulceration by ——
- regernation
- regeneration and fibrosis
liver:
- single short lived injury is healed by —
chronic injury by —
- regeneration
- cirrhosis
nervous system :
- CNS :
- preferial nerves:
- gliosis
- regernation
muscle :
- cardiac muscle :
- skeletal muscle
both by fibrosis
factors that influence healing are:
local and systemic effect
1. local effect :
* Poor vascular supply
* Infection
* Foreign material
* Excessive movement
* Poor approximation
* Size, site and type of injury
2. systemic effect:
SYSTEMIC FACTORS
* Age
* Nutrition (proteins, Vitamin C- collagen formation,
copper- cross linking of collagen, Zinc- conversion of
type III to type I collagen)
* Metabolic status (DM)
* Hormones (steroids)
* Malignancy
* Chemotherapy
* Radiotherapy
