Healing and repair   specialized tissue- 3
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Healing and repair specialized tissue- 3

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pathology lecyure

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Healing and repair   specialized tissue- 3 Healing and repair specialized tissue- 3 Presentation Transcript

  • Healing and repair - 2 Dr H.M.D.Moratuwagama Dept of Pathology
  • Complications of cutaneous wound healing
  • 1)Deficient scar formation Wound dehiscence / ulceration
  • 2.Incisional Hernia I
  • 3.a)Hypertrophic scar
  • 3.b)Keloid
  • •What is the difference between a hypertrophic scar and a keloid?
  • 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.
  • 3.c)Exuberant granulation
  • 4)Excessive contraction Formation of contractures
  • 5.Implantation cyst
  • 6.Marjolin's ulcer
  • 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
  • Healing in specialized tissue 1.Bone 2.GIT 3.Nervous system 4.Liver 5.Kidney 6.Muscle
  • Healing in specialized tissue Fracture healing 1)Procallous formation 2)Osseous callous formation 3) Remodeling
  • 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)
  • 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
  • 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
  • Gastrointestinal tract • Depends on the depth of injury 1)Mucosal erosions • Viable epithelium proliferate and fill the defect
  • 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
  • Nervous system Central nervous system • Nerve cells of the CNS , spinal cord and ganglia are permanent cells • Only glial cells proliferate – Gliosis
  • 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
  • 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
  • Kidney • Tubular cell damage with intact BM • Tubular epithelial cells regenerate • Glomerular damage scaring
  • 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
  • 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 .
  • 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