Healing and repair specialized tissue- 3


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Healing and repair specialized tissue- 3

  1. 1. Healing and repair - 2 Dr H.M.D.Moratuwagama Dept of Pathology
  2. 2. Complications of cutaneous wound healing
  3. 3. 1)Deficient scar formation Wound dehiscence / ulceration
  4. 4. 2.Incisional Hernia I
  5. 5. 3.a)Hypertrophic scar
  6. 6. 3.b)Keloid
  7. 7. •What is the difference between a hypertrophic scar and a keloid?
  8. 8. Hypertrophic scar is raised, erythematous, and remains within the boundaries of the original trauma or wound. A keloid, on the other hand, extends beyond the confines of the wound and is more nodular.
  9. 9. 3.c)Exuberant granulation
  10. 10. 4)Excessive contraction Formation of contractures
  11. 11. 5.Implantation cyst
  12. 12. 6.Marjolin's ulcer
  13. 13. Complications of cutaneous wound healing 1)Deficient scar formation • Wound dehiscence / ulceration 2) Incisional hernia 3)Formation of excessive amount of repair component a)Hypertrophic scar b)Keloid formation c)Exuberant granulation 4)Excessive contraction Formation of contractures 5) Implantation cyst 6) Rarely – neoplasia may develop Squamous cell carcinoma following burns
  14. 14. Healing in specialized tissue 1.Bone 2.GIT 3.Nervous system 4.Liver 5.Kidney 6.Muscle
  15. 15. Healing in specialized tissue Fracture healing 1)Procallous formation 2)Osseous callous formation 3) Remodeling
  16. 16. Fracture healing cont. 1) Procalus formation • Haematoma forms at the site of fracture • Fibrin clot forms the framework • Local inflammatory response- PMN , macrophages • In growth of granulation tissue • Callus formed of woven bone forms ( fusiform shape)
  17. 17. Fracture healing cont. 2)Osseous callus formation • On the procallus lamellar bone forms • Woven bone cleared by osteoclasts 3) Remodeling • Osteoclasts clear the excess bone • Osteoblasts lay down bone • External callus - Cleared away • Intemediate callus - Compact bone forms ( cortex) • Internal callus - Bone marrow forms
  18. 18. Complications of fracture healing 1) Fibrous union • Usually when immobilization is not done • False joints may also form (Pseudoarthrosis) 2)Non –union • In the presence of soft tissue between the fracture ends 3)Delayed union
  19. 19. Gastrointestinal tract • Depends on the depth of injury 1)Mucosal erosions • Viable epithelium proliferate and fill the defect
  20. 20. 2)Mucosal ulceration • Defect covered by blood • Macrophage remove debris • Granulation tissue form • Mucosa spread from the margin to the base of the ulcer • Muscle replaced by scar tissue • May lead to stenosis and obstruction
  21. 21. Nervous system Central nervous system • Nerve cells of the CNS , spinal cord and ganglia are permanent cells • Only glial cells proliferate – Gliosis
  22. 22. Nervous system cont. Peripheral nerves - Wallerian degeneration • With transection of nerve fibres the axon and the myelin sheath undergo degeneration upto the closest proximal node of Ranvier • Disintegrated fibres are phagocytosed • Regeneration occurs with sprouting of axons and proliferation of schwann cells from the proximal ends
  23. 23. LIVER • Hepatocytes have a high regenerative capacity • Injury leads to complete restitution of the tissue • However if connective tissue network is severely damaged fibrosis occur The eagle Ethon eating each day a part of the liver of Prometheus
  24. 24. Kidney • Tubular cell damage with intact BM • Tubular epithelial cells regenerate • Glomerular damage scaring
  25. 25. Muscle Cardiac muscle • Permanent cells • Replaced by scar tissue Smooth muscle • Limited regenerative capacity • With larger injury Skeletal muscle • Intact muscle sheath Damaged muscle sheath scar tissue form Properly oriented muscle form Fibrous scar
  26. 26. The healing of an injured skeletal muscle usually follows a constant pattern 1.Destruction phase-the rupture and ensuing necrosis of the myofibres, formation of a haematoma between the ruptured muscle stumps, and inflammatory cell reaction. 2.Repair phase - phagocytosis of the necrotised tissue, regeneration of the myofibres, and concomitant production of a connective tissue scar, as well as capillary in growth into the injured area. 3.Remodelling phase-regenerated myofibres mature, the scar tissue contracts and is re-organised, and the functional capacity of the muscle recovers .
  27. 27. Summary • The process by which healing occurs in a tissue is dependant on several factors – Type of cell , extent of injury etc • Depending on the type of wounds, healing process follows two pathways - Healing by primary intension - Healing by second intension • There are systemic and local factors that may delay wound healing • Healing in other specialized tissue also depends on the type of tissue and the extent of injury