tissue repair for essintial pathology

1. Tissue Repair
Ghida M Monasar
Presenter by
Supervisor by Dr . Khadiga mahmoud
Associate professor of pathology
Faculty of medicine & health science
Taiz university

2. Definition of repair
Is response of living tissue to replace any
surrounding tissue damage .
Is the body’s response to injuries in attempt to
restore normal structure and function .
Is process occur after tissues injury by regenerated
of damage tissues by new healthy one of the
same kind there lost or by deposited another
fibrous tissue (Scar) .

3. Types of repair
Repair of damaged tissues occurs by two types of
reaction :
1- regeneration by proliferation of remnant cells
( uninjured ) to replacement dead tissue by the
same kind
2-connective tissue deposition (scar formation)
- Fibrosis
- gliosis

5. Determines the types of repair
1 - Cells proliferation
2- Extent of damaged tissue
- severity
- duration
- size

6. Regeneration
Ability of tissue to replace its damaged components
and essentially return to normal state
That involved :
1- proliferation of cells that depend on capacity to
proliferate
2- interaction between cells ( growth factors )
3- extracellular matrix ECM

7. 1- Cell proliferation
Is a fundamental to development ,
maintenance tissue hemostasis and
replacement of dead or damaged cells .

9. Cell cycle
G0 cell is out of the cell cycle and don’t dividing
- resting phase –
G1 pre synthetic growth synthesis RNA ,
ribosomes
S DNA synthesis
G2 premitotic growth
M mitotic phase

10. Cells of the body are divided according to capacity
power of generation in cell cycle into three groups:
1- labile cells
have a high power of regeneration
2- stable cells
have a moderate power of regeneration
3- permanent cells
have No power of regeneration at all

11. continuous cell )
)
Labile cell
 Cells are constantly being lost ( infected or aging ) and must
be continually replaced by new cells that are derived from
stem cells and rapidly proliferation
As
 Hematopoietic cells in bone marrow
 Surface epithelia of squamous of skin , oral cavity , vagina ,
cervix
 Surface epithelia of cuboidal salivary glands , pancreas ,
biliary tract
 Surface epithelia of columnar gastrointestinal tract ,
endometrium of uterus , fallopian tubes , urinary tact

12. Quiescent cell )
)
Stable cell
 Cells do not proliferation under normal condition but
proliferate when there need
As
 Parenchyma of solid organs as liver , pancreas , kidney
 Endothelial cells
 Smooth muscle cells
 Bone and cartilage

13. Permanent cell ( static cell )
 Non proliferate cells can not regeneration
As
 Cardiac muscle
 Skeletal muscle
 Nerve cells
- central nervous ( astrocytes of brain , spinal cord ,ganglia
- but peripheral nervous show limited regeneration as
as schwann cells

14. 2- growth factors
 Growth factor activity is mediated through binding to specific
receptors, that influencing the expression of genes that can:
 1- Promote entry of cells into the cell cycle
 2- blocks on cell cycle and promoting replication
 3-Prevent apoptosis
 4-Enhance biosynthesis of cellular components (nucleic
acids, proteins, lipids, carbohydrates) required for a mother cell
to give rise to two daughter cells

16. 3- extracellular matrix
The ECM is a network of interstitial proteins that
constitutes a significant characteristic of any
tissue.
Cell interactions with ECM are critical for
development and healing,
as well as for maintaining normal tissue
architecture

18. Liver repair
 mild injury e.g hepatitis A , if the cytoarchitecture is
intact regeneration of hepatocytes with restoration
to normal
Sever injury e.g hepatitis C if the cytoarchitecture
is lose regenerative nodules to show of liver cell
plates and increased fibrosis around nodules lead
to cirrhosis

20. Regeneration of liver by two major
ways ;
1-from partial hepatectomy
Resection of up to 90% of the liver can be
corrected by proliferation of the remaining
hepatocytes this process controlled by cytokines
IL- 6 that produced by kupffer cells and by growth
factor HGF ( hepatocyte growth factor )

21. Regeneration of liver by two major
ways
2- from progenitor cells
When proliferative capacity of hepatocytes are
impaired as after chronic liver injury or
inflammation
Progenitor contribute to repopulation called canals
of hering , this topics still active investigation

22. Factor impair tissue repair
1- infection
is one of the most important causes of delayed repair
2-diabetes
increasing susceptibility to infection and delayed repair
3-nutritional status
Protein malnutrition , vitamin C deficiency that decreased
collagen synthesis
4-mechanical effects
Movements , pressure and torsion delayed repair
5-poor perfusion
Ischemia delayed repair

23. 6-Glucocorticids drugs ( steroids )
that inhibit TGF-B production and interfere collagen formation
delayed and diminish repair
7-extent of tissue injury
types ( mildsever ) and location ( surficial depth ) of injury
8- foreign bodies
Fragments of glass , wood , …