Wound Healing Flashcards
(26 cards)
Wound healing overview
Regeneration definition and example
Regeneration is the replacement of lost or damaged tissue by that of a similar type derived from the proliferation of the surrounding undamaged cells
Example is Human Liver
Repair definition
What are the two paths of repair?
Repair is the replacement of lost or damaged tissue by granulation tissue which later matures into fibrous scar tissue.
Wound healing - difference between healing and repair
• The process of healing and repair is similar in many tissues
• Healing is usually described with reference to a small skin wound.
Skin / mucosa structure
Healing a small skin wound- what are the two ways of healing a small skin wound?
Healing by primary intention = the wound edges are in close apposition
Healing by secondary intention. = the wound is more extensive and the wound edges are widely separated
What are the steps involved in wound healing? PART 1
Healing of a small skin wound -1 hour?
connective tissue and epithelium
1) HAEMOSTASIS
•platelet plug formation
•fibrin clot formation
Factors which inhibit the formation of the platelet plug and fibrin clot inhibit wound healing.
Examples: Asprin; Warfarin; factor VIII deficiency
SEE SLIDES 7-9
What are the steps involved in wound healing? PART 2
Healing of a small skin wound - 48 hours?
connective tissue and epithelium
• inflammation
• macrophage infiltration
• debridment
What are the steps involved in wound healing? PART 3
Healing of a small skin wound - 2-5 days?
connective tissue
Granulation tissue formation
• endothelial cell and fibroblast proliferation
• new blood vessels migrate from the wound edges
• small blood vessels are accompanied by fibroblasts and inflammatory cells
• collagen extra-cellular matrix
Granulation tissue -a loose cellular connective tissue with many plump, synthetic fibroblasts; dilated, irregular blood vessels and inflammatory cells.
What are the steps involved in wound healing? PART 4
Healing of a small skin wound - >5 days?
connective tissue
Maturation
• decreased cellularity
• decreased vascularity
• remodelling of collagen matrix
• (involves matrix metalloproteinases and other proteases)
• collagen cross linking
What are the steps involved in wound healing?
Healing of a small skin wound 1-3 days?
epithelium
Re-epithelialisation
• Proliferation of basal epithelial cells adjacent to the wound
• Migration of basal epithelial cells across wound bed under fibrin scab to restore epithelial continuity
• Epithelial cells differentiate and stratified squamous structures re-form
Healing of a small wound summary
See histology slides
WHAT FACTORS ARE IMPORTANT IN CONTROLLING WOUND HEALING ?
What impacted wound healing?
Mononuclear (macrophage precursor) depletion in guinea pigs dramatically impaired wound healing
Macrophage function part 1
Macrophage function 2
What growth factors do macrophages produce ?
What are the two types of factors important in wound healing?
Systemic
Local
What are the systemic factors important in wound healing?
• Age
• Nutritional status. (e.g. protein deficiency; vitamin-C deficiency; others)
• Iatrogenic (e.g. glucocorticoids)
• Pre-existing medical conditions (e.g. diabetes)
What are the local factors important in wound healing?
• Blood supply
• Infection
• Persistent irritation
• Poor wound stability
• Poor apposition of wound edges
• Skin wounds: direction of incision -Langers lines
• Ionising radiation
What are some of the complications of wound healing?
(5)
What is a keloid?
What is Hypertrophic scarring?
What does a keloid look like?
