[A] 1.46 Regeneration of connective tissue and blood vessels. Wound healing Flashcards
Which connective tissues can be regenerated?
- Fibrous CT
- Elastic CT
- Cartilaginous tissue
- Bone
Regeneration of fibrous connective tissue in the blood vessels
Completed by:
- Rouget cells: Multipotent cells of the adventitia
- Scattered undifferentiated cells of organs
Almost unlimited process
Angiofibroblast tissue
- Composed of fibroblasts
- Produce new vessels from:
- Endothelium of capillaries
- Adventitia of surrounding blood vessels
- New vessels provide fibroblasts with nutrients
Summarise fibroblasts
- Elongated or stellate shape
- Hugh proliferative capability
Fibroblast maturation
Fibroblast → Fibrocyte
- Elongation and darkening
- Tropocollagen exits the fibroblasts
- Tropocollagen → fibrils → fibres
- Fibres thicken
Blood vessel healing
Angiogenesis - only the capillaries
- Solid cell bundles on the wall of blood vessels
- Canal formation - central cavity develops, communicating with the capillary lumen
- Endothelium formation
Regeneration of elastic fibrous connective tissue
Similar to collagen fibrous connective tissue
- Elastic fibres will be produced
- First appearance in 4 weeks
- More limited
- Wont reach original elasticity
Regeneration of cartilaginous tissue: Overview
- Requires intact perichondrium to regenerate
- Production of fibrous connective tissue
Limited regeneration capacity
Regeneration of cartilaginous tissue: Steps of the process
- Secretion of ICM
- Fibre production
- Chondroblasts → Chondrocytes
- Hyalinisation of IC substance
- Healing complete
Types of injury to the bone
- Fracture
- Complete - Simple, multiple
- Incomplete - Fissure, impression
Fracture results in formation of a callus
Callus:
- Define
- Give the types
The bony healing tissue forming around the ends of a broken bone
Types:
- Periostal (periosteum)
- Cortical (compacta)
- Endostal
Primary regeneration of the bone: Healing types
- Contact healing
- Fissure healing
Primary regeneration of the bone: Contact healing
- No gap between the broken ends
- No blood clot formed, fast, no callus
- Osteoblasts from the adventitial of cortical blood vessel
Primary regeneration of the bone: Fissure healing
- Narrow fissure
- Osteoblasts from the periosteal and endosteal blood vessels
- No callus
Secondary regeneration of bone
Separated fractured bone ends
- Limited movement
- Angiogen callus production
- Fibrous union (scar tissue)
- Unsatisfactory end-result
Give the steps of fracture healing
- Hematoma (Btw. broken ends)
- Connective tissue callus
- Osteoid/cartialgenous callus
- Provisional osteoid callus
- Permanent osteoid callus
What occurs in the connective tissue callus?
- Angiofibroblast proliferation
- Macrophage activity
What occurs in the osteoid/cartilaginous callus?
- Osteoblast activity
- Hyalin cartilage formation
What occurs in the provisional osteoid callus?
Gradual fusion “Framework”
Permanent osteoid callus
Final lamellar bone
Regeneration of the vessels
- Only in capillaries
- (see angiofibroblast)
- Large blood vessels
- Cut wall united by connective tissue
- Scar
- Covered by endothel and adventitia
- Adventitia and intima are thickened
Wound healing is either…
- First intention wound healing
- Second intention wound healing
First intention wound healing
Sanatio per primam intentionem
- No/minimum tissue loss
- No/minimal bacterial contamination
- Edges brought together
- Cuts, surgical wounds with stitches
Second intention wound healing
Sanatio per secundam intentionem
- Major tissue loss
- Granulation tissue fills gap
- Epithelisation
- Vulnerable lighter area with no hair follicles
Give the regenerative processes after injury
- Haemostasis - immediate
- Inflammation - 24-96hrs
- Proliferation - angiogenesis, epithelisation
- Remodelling - 3-4 weeks
Factors affecting wound healing
- Wound location, blood supply, mechanical trauma
- Age & nutrition
- Drugs
- Foreigin bodies, infections, tumours
- Autoimmune diseases, obesitas
