Regeneration and repair

Functional repair (regeneration) vs fibrous repair

Regeneration- the growth of cells and tissues to replace lost structures and recover normal function (no scar)

Repair- process where severely damaged/non-regenerable tissue is replaced by connective tissue → scar with loss of specialised function

What are the stages of wound healing

1. Haemostasis: vessels open → clot/ scan seals them close

2. Inflammation: cytokines released + phagocytosis

3. Proliferation: regrowth of structures by stem cells (regeneration and repair)

4. Remodelling: regaining function (scar disappearing)

What does granulation tissue consist of ?

• endothelial cells and capillaries

• Fibroblasts and my fibroblasts

• Type I collagen

• Chronic inflammatory cells

What is the function of granulation tissue?

• fills the gap

• Angiogenesis to supple o2 and nutrients (endothelial + progenitor cells)

• Contact and close the wound (myofibroblasts)

• Help restore lost tissue (parenchymal cells)

What are some complications of fibrous repair?

• Insufficient fibrosis eg. Hernia, ulceration

• Reproduction of fibre scar tissue → keloid scar

• Excessive scar contraction → Obstruction of tubes/disfiguration

• Formation of adhesions → compromise organ function/block tubes

• Loss of function

Difference between primary(complete regeneration) and secondary intention (fibrous repair)

Systemic factors affecting regeneration and repair

• age

• Disease/ health eg. Diabetes, obesity

• Drugs eg.steroids

• Oxygen delivery eg. Anaemia, hypoxia

• Malnutrition eg. Vit C deficiency, lack of protein

Local factors affecting regeneration and repair

• type, size and location of wound

• Blood supply

• Local infection

• Necrotic tissue

• Mechanical stress/ physical factors: protection eg. Dressings , surgical technique

What is wallerian degeneration and why does it happen?

What is traumatic neuroma?

A benign growth of nerve tissue that occurs in response to injury

Process of bone fracture repair **

1. Haematoma fills the gap and surrounds the injury, inflammation

2. Granulation tissue forms: