Tissue Repair

• A non specific immune system response to tissue injury and damage

  Inflammation
• The inflammation process begins when blood vessels dilate in the affected area
• This (Inflammation) dilation leads to increased capillary permeability
• What cells move to the damages area?

  Phagocytic cells
• What chemical messenger is released?

  Histamine
• What are the five cardinal signs of inflammation

  Redness

  heat

  Pain

  Swelling

  Loss of function
• What must happen before wound healing can begin?`

  Phagocytic cells remove cell debris
• Cells with excellent regenerative capacity and continuous division

  Labile Cells
• What are the three examples of having labile cells

  Skin

  Lining of GI tract

  Blood forming tissue
• Cells with lower turnover than can still produce new cells when needed

  Stable cells
• 2 examples of stable cells

  Hepatocytes (Liver cells)

  Osteoblasts (Bone cells)
• Cells incapable of producing new cells

  Permanent cells
• 2 example of Permanent Cells

  Mature nerve cells

  Cardiac Muscle cells
• 3 stages of wound healing

  Contraction of wound

  Tissue repair

  Tissue regenration
• Replacement of damaged tissue by identical cells

  Regeneration
• Will there be scarring if the epithelial basement membrane is not damage?


  No scarring will occur
• Process by which damaged tissue is restored through regeneration or scarring


  Tissue repairs
• What occurs when a wound extends past the basement membrane?

  Both epithelial and connective tissue response
• What type of tissue forms during deep wound healing?

  Granulation tissue
• What is the end result of deep wound healing

  Scarring
• The process by which damaged tissue repairs itself through several distinct stages

  Wound healing
• What happens in the initial stage of wound healing?

  Bleeding occurs and inflammatory response is triggered
• What forms at the wound site after several hours

  Scab
• What cells migrate to the wound site during repair

  Macrophages

  Fibroblasts

  Migratory epithelial cells
• What tissue forms under the scab during healing

  Granulation tissue
• What happens to the scab after one week

  Undermined by epidermal cells migrating over fibroblast meshwork
• What is the final result of wound healing

  Scar tissue forms in dermis with shallow depression at the injury site
• Protective covering that forms over a wound during healing

  Scab
• Scab function


  Partially isolates the wound region during healing
• Dense fibrous tissue that replaces normal tissue after injury

  Scar tissue
• What cells are responsible for creating scar tissue

  Fibroblasts in the dermis
• What is the long term effect on the overlying epidermis

  Gradual elevation by continued fibroblast activity
• The process by which the body repairs damaged tissue following injury

  Wound healing
• What is the sequence of events following tissue injury

  Injury occurs

  Platelet aggregation

  Blood clot forms and fibrin deposited

  Influx of macrophages

  Increase in fibroblast proliferation

  Collagen fibers form

  Extracellular matrix develops

  Epithelial cells divide and cover wound
• Wound healing where edges are close together with minimal tissue loss

  Primary intention
• What are the key characteristics of Primary intention

  Close wound edges

  Minimal tissue loss

  Minimal cell division

  Little to no scarring
• Wound healing where edges are far apart with significant tissue loss

  Secondary interntion
• What are the key characteristics of secondary intention

  Edges far apart

  Large tissue loss

  Extensive cell division

  Significant scar formation
• The structural support network in healing tissue

  Extracellular Matrix
• What are the two main components

  Fibronectin and proteoglycans