Flashcards in Regeneration and reapir Deck (23):
What are the 3 tissues of the body ?
Labile tissue- Proliferate, replaced . Surface epithelia and Lining of mucosa
Stable- Low level normally but can proliferate in stimuli to reconstruct tissu- Liver, Kidney and pancreas
Permanent- Left cell cycle - Neurones , skeletal and cardiac msucles
What is asymmetric replication
shown by stem cells . Daughter cell remains as stem cell but the other is a mature end cell
What are embryonic Stem cells ?
Totipotent- give arise to any tissue
What are adult stem cells?
Unipotent- only into 1 form of adult cell
What are haematopoietic stem cells ?
Multipotent - several cells in adult stem cells
What happens in regeneration in Permanent tissue, especially in neurones .
Scaring - stem cells cant perform
Gliosis - Glial cells fill in gaps
What happens in cell cycle for Stable tissue?
G0 to G1 . stem cells proliferate slowly but persistently
Why might fibrous regeneration occur?
collagen framework is destroyed
On going chronic inflammation
Necrosis of special parenchymal tissue
What are the processes of Fibrous repair?
2. Growth of endothelial cells which allows angiogenesis
3. Fibroblasts and myofibroblasts -collagen - contraction- Granulation tissue
4. Granulation tissue - less vascular - matures into fibrous scar
5. Scar shrinks due contraction of fibrils
Steps of collagen synthesis
1. preprocollagen in cell
2. modified to pro-collagen which goes into Triple helix
3. Secreted from cell and cleaved to collagen
4. Cross linking
Vit C needed for hydroxylation of pro-collagen - prolyl hydroxylase . Proline to hydroxy proline
Ehlers- Danlos Syndrome
Six inherited disorders collagen lack tensile strength
Organs weak - ruptures
not enough collagen made - blue sclera - translucent, brittle bone
Type 4 collagen is abnormal . Glomerular , lens of eye and cochlea - chronic renal failure
What are growth factors and what are they coded by?
Short distance - autocrine or paracrine or endocrine stimulating cell proliferation . coded by proto oncogenes
What are the types of growth factors
Platelet Derived- Increase Fibroblasts , SMC and Monocytes
Tumours Necrosis factor- Fibroblast migration , prof and collagenase
What is contact inhibition ?
Cells replicate until they touch other cells
What allows cell to cell adhersion ?
Cell to EXCM?
When does primary intention occur?
Closed , incisional , non -infected sutured wounds
what is the process of healing by Primary Intention ?
3. Migration of cells
6. Scar Maturation
When is is healing by secondary intention occurring ?
Wounds with tissue loss
more intense inflammation - Granulation tissue for the margins
contraction . Thinner epidermis .
Stages of healing bone fractures
2. Fibrin mesh of granulation tissue
3. Soft callus - Fibrous tissue and cartilage
4. Hard callus - oestoblasts
5. Formation of lamellar bone- Haversian canals and Volkmans