A4 Case Study: Repair Flashcards
What is the difference between a partial thickness wound and full thickness wound?
- Partial thickness wound: Loss of superficial (epidermis and partial of the dermis).
- Full thickness wound: wound extends through the dermis (subcutaneous fat and sometimes bone).
How is repair different in each scenario?
Depending on the thickness of the wound.
Healing of partial thickness wound regenerates quicker as it is superficial (Heals by reepithelialisation), whereas full thickness wound will take longer tor repair and leave a scar and potentially heal from the body to top
What is the difference between primary, secondary, and delayed primary intention healing?
- Primary intention: (narrowed wound) Wound edges have been pulled together by surgical stitching etc, little bacterial contamination
- Secondary intention: (wider wound) when wound is too large to be pulled together. Heals from the base and upwards.
- Delayed primary intention: This process allows for the formation of some granulation tissue to form before excising and suturing (stitching)
(left opened and stitched later due to weird shape or contamination
What cells are involved in wound healing?
- Platelet
- Leukocyte: Neutrophil
- Macrophage: Cytokines
- Connective tissues: Fibroblast (myofibroblast), angioblasts
- Epithelial cells: Keratinocyte
What are the key events and purpose of the inflammatory phase of healing?
Stabilise the wound Phase
- Wound fills up with blood
- Acute inflammatory response
- Clotting for bleeding to stop
- Scab formed
- Clot retracts (dry out) draws wound edges together
- Fibronectin produces act as glue bonding, collagen, proteoglycans, fibrin together
- Inflammatory exudates are removed
Purpose: to stabilise the wound, controls bleeding and prevent infection
What are the key events and purpose of the fibroblastic phase of healing?
- Partial thickness wounds: Epithelialisation
- Full thickness wound: Connective tissue and blood vessel formation.
The connective tissue and vessel formation/Granulation
1. Fibroblast migrates and proliferate
2. Deposition of extracellular matrix (collagen)
3. Angiogenesis
4. Epithelialisation
Purpose: to form granulation, scar tissue
What is granulation tissue?
- Fibroblasts (myofibroblast) and vascular endothelial cells proliferate forming granulation tissue to replace dead or loss tissue in the dermis
- Bright red in colour (healthy)
How does angiogenesis occur?
- Angiogenesis: Formation of new blood vessels
- crucial for granulation
- Angioblast: New vessels bud or sprout off existing local vessels
- Proteolytic degradation of the basement membrane of the
parent vessel - Migration of endothelial cells towards the angiogenic stimulus
- Proliferation of endothelial cells behind the leading front of
migrating cells - Maturation of the new endothelial cells and organisation into proper vessels
- Macrophages: Once healing is done the vessels in area turns white due to vessels dying by macrophage
How does reepithelialisation happen?
Repepithelialisation: resurfacing of a wound with epithelium (keratinocyte)
- epidermis begins to regenerate starting off with
- Migration of epithelial cells occurs out of hair follicles
Proliferation and alignment
- The basal epidermal cells detaches from basement membrane and to migrate a greater rate.
- As they undergo mitosis they push those cells forward.
- Cells migration changes direction when encounter each other by CONTACT INHIBITION.
Repepithelialisation:
- Migration continues until wound is surfaced with one cell layer
- After the bassal layer is created, cells then undergo mitosis pushing cells up creating the whole epidermis
- EPIDERMAL GROWTH FACTOR: stimulate epidermal cells to divide and replace the cells left
What are the key events and purpose of the maturation phase of healing?
- Wound matures and remodels
- Collagen content increases from type 3 change to type 1
- End result of full thickness wound healing is a scar tissue
What is scar tissue and how does this differ from normal tissue?
Scar tissue: Growth of tissues where skin has healed after an injury.
differs
- Inactive fibroblasts
- Dense collagen
- Relatively few vessel (Pale looking)
- Fragments of elastic tissue
- Extracellular matrix
Scar tissue differs to normal tissue as scar tissue produced more collagen content and more dense than normal tissue when it coms to wound maturation
What are some of the complications of wound healing?
- Hypergranuation: produce too much granules, not allowing epidermis growth
- Hypertrophic Scarring: abnormal thick raised scar
- Wound Dehiscence: wound open up
- Ulceration: break of the skin surface
- Contractures: deformed of muscles, joints etc
- Hypotrophic Scarring
- Keloid Scarring: clots wall of wound, raised scar
Phases of Wound Healing?
- Inflammatory Phase
- Fibroblastic Phase
- Maturation Phase
what are the 3 ways full thickness wound heals?
3 ways: primary, secondary, or delayed primary intention healing
