Regeneration and reapir

Question 1

What are the 3 tissues of the body ?

Answer 1

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

Question 2

What is asymmetric replication

Answer 2

shown by stem cells . Daughter cell remains as stem cell but the other is a mature end cell

Question 3

What are embryonic Stem cells ?

Answer 3

Totipotent- give arise to any tissue

Question 4

What are adult stem cells?

Answer 4

Unipotent- only into 1 form of adult cell

Question 5

What are haematopoietic stem cells ?

Answer 5

Multipotent - several cells in adult stem cells

Question 6

What happens in regeneration in Permanent tissue, especially in neurones .

Answer 6

Scaring - stem cells cant perform

Gliosis - Glial cells fill in gaps

Question 7

What happens in cell cycle for Stable tissue?

Answer 7

G0 to G1 . stem cells proliferate slowly but persistently

Question 8

Why might fibrous regeneration occur?

Answer 8

collagen framework is destroyed
On going chronic inflammation
Necrosis of special parenchymal tissue

Question 9

What are the processes of Fibrous repair?

Answer 9

1. Phagocytosis
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

Question 10

Steps of collagen synthesis

Answer 10

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

Question 11

Scurvy Pathology

Answer 11

Vit C needed for hydroxylation of pro-collagen - prolyl hydroxylase . Proline to hydroxy proline

Question 12

Ehlers- Danlos Syndrome

Answer 12

Six inherited disorders collagen lack tensile strength

Organs weak - ruptures

Question 13

Osteogenesis imperfecta

Answer 13

not enough collagen made - blue sclera - translucent, brittle bone

Question 14

Alport Syndrome

Answer 14

Type 4 collagen is abnormal . Glomerular , lens of eye and cochlea - chronic renal failure

Question 15

What are growth factors and what are they coded by?

Answer 15

Short distance - autocrine or paracrine or endocrine stimulating cell proliferation . coded by proto oncogenes

Question 16

What are the types of growth factors

Answer 16

Epidermal
Vascular Endothelial
Platelet Derived- Increase Fibroblasts , SMC and Monocytes
Tumours Necrosis factor- Fibroblast migration , prof and collagenase

Question 17

What is contact inhibition ?

Answer 17

Cells replicate until they touch other cells

Question 18

What allows cell to cell adhersion ?

Cell to EXCM?

Answer 18

Cadherins

Intergrins

Question 19

When does primary intention occur?

Answer 19

Closed , incisional , non -infected sutured wounds

Question 20

what is the process of healing by Primary Intention ?

Answer 20

1. Heamostasis
2. Inflammation
3. Migration of cells
4. regeneration
5. early scarring
6. Scar Maturation

Question 21

When is is healing by secondary intention occurring ?

Answer 21

Wounds with tissue loss
Excisional surgery
more intense inflammation - Granulation tissue for the margins
contraction . Thinner epidermis .

Question 22

Stages of healing bone fractures

Answer 22

1. Haematoma
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
6. Remodelling

Question 23

Factors affecting repair:

Answer 23

Local: Size , Blood supply, Protecetion , surgical technique
Systemic: Age , ANAEMIA, DIABETES, drugs