Wound Healing and Skin Disorders

Wound

The disruption in bodily tissues

Wound Healing

A regenerative process in which an organism replaces or repairs damaged tissues following an injury

Epidermal Wound Healing

Only occurs when superficial wounds affect the epidermis— minor injury

Dermal Wound Healing

Only occurs when wounds extends to the dermis or subcutaneous layer— extensive injury

Wound Healing: Haemostasis

The second phase of wound healing that occurs to stop any additional bleeding

• Vasoconstriction: Damaged blood vessels will restrict to prevent blood loss

• Platelet Plug Formation: Platelets will form a loose blood clot around the edges

• Coagulation: Platelets will activate fibrinogen to produce a fibrin mesh to fully form a blood clot

Wound Healing: Inflammation

The second phase of wound healing that occurs to eliminate microbes for tissue repair

• Inflammation: Mast cell is released to produce histamine to dilate the blood vessels and increase the permeability of blood vessels

• Neutralization: Monocytes develop into macrophages to consume microbes

Wound Healing: Proliferation

The third phase of wound healing that occurs to begin tissue repair

• Granulation Tissue Formation: Fibroblast begin secrete matrix of scar tissue (collagen fiber and glycoprotein) to fill the wound

• Angiogenesis: Blood begins to supply nutrients tissue for tissue repair because it demands a lot in this process

Wound Healing: Remodeling

The last phase of wound healing that occurs to begin tissue repair

• Maturation: The scab in the wound site would eventually become one with the skin

• Wound Contraction: The scab finally sloughs off once the skin restores its normal thickness

Fibrosis Scarring

Scar tissue formation for the epidermis wound healing

Hypertrophic Scarring

A raised scar tissue formation that’s within the boundaries of a previous wound from excessive collagen production

Keloid Scar

A raised, itchy scar tissue formation that’s beyond the boundaries of a previous wound from excessive collagen production

Age-Associated Changes: Melanocytes Production

Melanocyte activity decreases, increasing the risk of gray hairs and sensitivity to sunlight

Age-Associated Changes: Sebaceous Production

Oil secretion decreases, making the skin more dry and scaly

Age-Associated Changes: Thinner Skin

Epidermis slowly its replication capacity, increasing vulnerability to injuries, infections, abrasions

Age-Associated Changes: Diminished Immune Response

The number of dendritic cells are reduced by half, increasing vulnerability to infection and damage

Age-Associated Changes: Thinner Dermis

Protein fibers starts becoming thinner and weaker, creating sagging and wrinkling

Age-Associated Changes: Vitamin D Synthesis

The metabolic activities decrease, resulting in muscle weakness and brittle bone

Burn Tissue Damage

Caused by extreme heat, radiation, or chemicals, with the associated dangers of dehydration, electrolyte imbalance, circulatory shock, diminished immune responses

Burn: The Rules of Nine

An assessment to estimate the total body surface area affected by burns

Head and Neck: 9% total

Upper Limb: 9% total

Front Torso: 18% total

Back Torso/ 18% total

Lower Limb: 18% total

Genitalia: 1% total

First Degree Burn

Minor burn that damages the epidermis, causing redness and pain without blistering (e.g., mild sunburn)

Second Degree Burn

Partial-thickness burn that damages the epidermis and part of dermis, causing redness, pain, blistering, and swelling (e.g., scalding)

Third Degree Burn

Full-thickness burn that damages the epidermis, dermis, and hypodermis, causing severe scarring, numbness, and reduced regeneration rate (e.g., fire burn)

Fourth Degree Burn

A severe burn that damages the deep tissue, such as muscle or bone, causing the loss of function in the affected part (e.g., explosion)

• This requires a skin graft to replace the function of skin

Critical Burns

Burns are considered critical if:

• Second degree burns cover over 25% of the body

• Third degree burns cover over 10% of the body

• Third degree burns cover the face, hands, or feet

Cancer

A disease caused by uncontrolled cellular division that disrupts bodily function because they lack specialization and differ

Cause of cancer at the cellular level

Genetic errors that duplicate and divide, leading to additional mutations

Telomerase in cancer

Allows cells to divide indefinitely by preventing telomere shortening

Benign tumor

Encapsulated, non-invasive tumor

Malignant tumor

Cancerous tumor that invades surrounding tissue

Carcinoma

Cancer of epithelial tissue

Skin cancer indicators: ABCDE rule

Asymmetry, irregular border, varied color, diameter >6 mm, changing or elevated patch

Basal Cell Carcinoma

The most common skin cancer that develops mutations from the overexposure of UV rays, and they are the least lethal

Squamous Cell Carcinoma

A common skin cancer that has an uncontrolled growth of abnormal squamous cells from overexposure to UV rays

Malignant Melanoma

The most dangerous skin cancer that has mutated melanocytes that metastasize through the lymphatic system from overexposure to UV rays

• Early melanoma has the survival rate of 97% through surgical removal of the tumor

• Late melanoma has the survival rate of 14% if it undergo metastasis

Pressure Ulcers

The damage areas of skin and tissue caused by a constant deficiency of blood flow from prolonged pressure, friction, and shear