Wound Healing of skin

Question 1

Describe epithelial wound healing, focusing on types of wounds & the two major steps & restoration of integumentary function. Discuss the depth of the wound relative to the basement membrane & dermis. Discuss the role of hemidesmosomes, desmosomes & contact inhibition in epithelial wound healing.

Answer 1

Epithelial wound healing refers to abrasions, cuts, and minor burns. In epithelial wounds, there is no, or only slight, penetration into the dermis. Stratum Basale cells break away from desmosomes(neighboring cells) and hemidesmosomes(basement membrane) to migrate laterally to bridge the wound. When two sides meet to seal the wound, contact inhibition takes place, stopping migration, and new desmosomes and hemidesmosomes are built to hold the epidermal cells together. Then, proliferation takes place and normal superficial differentiation of epidermal cells from the basal to apical replaces the epidermis and complete restoration of epidermal function is normal.

Question 2

Describe deep wound healing, referencing the impact on the basement membrane and dermis. Name and describe the 4 steps, paying attention to which 2 also occur in epithelial wound healing. Discuss dermal aspects of wound healing, focusing on scar tissue & potential loss of dermal function

Answer 2

In deep wound healing, the damage reaches the dermis or subcutaneous layer of the skin.

Step 1 in deep wound healing is the inflammatory phase. In this phase, blood clots from damaged vessels fill the wound and nearby blood vessels dilate to inflame, bringing in immuno-active cells to the site for protection during healing.

Step 2 is the Migratory phase where the blood clot becomes a scab. Stratum Basale Cells in the epidermal migrate and bridges the wound. Fibroblasts also migrate along fibers to create scar tissue made of collagen fibers and glycoproteins. Damaged blood vessels begin to regrow.

Step 3 is the proliferative phase where epidermal cells differentiate superficially from stratum basale to stratum corneum.

The last step is the maturation phase where the scab falls off. Collagen fibers arrange themselves to look like dense irregular connective tissue and blood vessels are restored.

Steps 2 and 3, the Miogrratory and Proliferative phase, also occurs in epithelial wound healing.
Loss of some functions of the integumentary system is normal (elasticity, sudoriferous or sebaceous glands, lost hair).