Wound healing and repair Flashcards Preview

Z- Pathology > Wound healing and repair > Flashcards

Flashcards in Wound healing and repair Deck (16)
Loading flashcards...

what are classifications of cell types?

-labile -multiply continually throughout life e.g. bone marrow
-Stable - only multiply when receive stimulus to do so)
-Permanent - cannot multiply


what is restitution?

Restitution means the complete restoration of the tissues to normal after an episode of acute inflammation


what factors favour restitution?

-Minimal cell death and tissue damage
-Occurrence in an organ or tissue with regenerative capacity eg liver
-Rapid destruction of the causal agent
-Rapid removal of fluid and debris by good local vascular drainage


what is needed for complete repair (restitution)?

-Labile and stable cell populations
-Death of permanent cell populations must be repaired with scar
tissue formation
-Tissue architecture must be preserved


what does repair by connective tissue fibrosis involve?

1. Angiogenesis- formation of new blood vessels
2. Migration and proliferation of fibroblasts
3. Deposition of collagen
4. Maturation and organisation of fibrous tissue - remodelling


what is organisation of tissues and what factors favour organisation?

Organisation of tissues is their replacement by granulation tissue
• Large amounts of fibrin formed
• Substantial necrosis
• Exudate and debris cannot be removed or discharged


what happens during organisation?

Much skin is completely destroyed and the underlying tissue is undergoing repair
The damaged area is being replaced by vascular granulation tissue


what is angiogenesis critical to?

i) Chronic inflammation and fibrosis
ii) Tumour cell growth
iii) Formation of collateral circulation


what are the stages of organisation?

1. angiogenesis
2.migration and proliferation of fibroblasts
3. deposition of collagen
4. tissue remodelling/organisation
(look into more detail in slides)


Summarise wound healing..

Induction of acute inflammatory response
o Regeneration of parenchymal cells (if possible!)
o Migration and proliferation of parenchymal and connective tissue cells
o Synthesis of collagen
o Remodelling/organisation of connective tissue and parenchymal components


what is the difference between repair with scarring in the first intention and the second intention?

First intention - surgical scar -Closely apposed edges Minimal granulation tissue Minimal fibrosis

Second intention - ulcerated surface -Edges widely separated Prominent granulation tissue Prominent fibrosis


Describe healing by first intention.

1. Limitedcelldeath
2. Basementmembrane
3. Incisional space fills with
4. Scab forms
5. Neutrophils move towards clot
6. Theepidermisthickensatits cut edges
7. Epidermalcellsmigratealong cut margins of dermis
8. Epithelial cells fuse in the midline beneath the surface scab
9. Day 3 neutrophils largely replaced by macrophages
10. Day 5 granulation tissue invades incision space
11. Collagen fibres bridge the incision
12. Epidermis recovers two normal thickness


How is second intention different?

1. Large defects involve more fibrin and more necrotic tissue therefore inflammatory reaction more intense
2. Much larger amounts of granulation tissue
3. Wound contraction plays an important role in reducing size of defect


what local factors influence wound healing?

Infection – single most important cause of delay in healing
- Mechanical factors – ie early motion of wounds delays healing
-Foreign bodies – ie sutures or glass
-Size, location and type of wound – wounds heal better in richly vascularised areas


what systemic factors influence wound healing?

Nutrition – wound healing profoundly influenced by ability to synthesise protein and collagen
-Metabolic status – diabetes is associated with delayed healing
- Circulatory status – an adequate vascular supply is essential for normal cellular function (hypoxia, reduced local nutrition)
- Hormones – glucocorticoids are anti-inflammatory but impair collagen synthesis


what are pathological aspects of wound repair?

1. Deficientscarformation–wounddehiscence/ulceration
2. Excessive formation of repair components – keloid scar
3. Formation of contractures – exaggerated contraction results in deformity of the wound and surrounding tissues