A&P Honors: Ch. 5.9 — Skin Cancer and Burns

What are the most common skin disorders?

Bacterial, viral, or yeast infections.

What are less common skin conditions but more damaging?

Skin cancer and burns.

What is the most common type of skin cancer?

Skin cancer.

What is the single most important risk factor for skin cancer?

Exposure to the UV radiation in sunlight and tanning beds.

What are dimers?

Lesions formed when adjacent pyramidine responds to UV damage.

What are the three major forms of skin cancer?

Basal cell carcinoma, squamous cell carcinoma, and melanoma.

Which of the skin cancers is the least malignant?

Basal cell carcinoma.

What happens during basal cell carcinoma?

Stratum basale cells proliferate, invading the dermis and subcutaneous tissue.

Where does basal cell carcinoma occur more often?

On sun-excised areas of the face.

What do basal cell carcinoma appear as?

Shiny, dome-shaped nodules that later develop a central liver with a pearly, beaded edge.

Describe basal cell carcinoma.

Slow-growing and metastasis seldom occurs.

What is the second most common skin cancer?

Squamous cell carcinoma.

What does squamous cell carcinoma arise from?

The keratinocytes of the stratum spinosum.

What does the lesion of squamous cell carcinoma appear as?

A scaly reddened papule that arises on the head and hands.

Describe squamous cell carcinoma.

Grows rapidly and metastasize if not removed.

Which is the most dangerous skin cancer?

Melanoma.

What is melanoma?

Cancer of the melanocytes.

Describe melanoma.

Highly metastatic and resistant to chemotherapy.

Where can melanoma occur?

Wherever there is pigment.

What is the key to surviving melanoma?

Early detection.

What rule should be used when examining moles or pigmented spots?

ABCD rule.

What does the A stand for in ABCD?

Asymmetry.

What does the B stand for in ABCD?

Border irregularity.

What does C stand for in ABCD?

Color.

What does the D stand for in ABCD?

Diameter.

Some experts add the letter E, what does it mean?

Evolution.

What is a burn?

Tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals.

What is the threat to life resulting from severe burns?

Catastrophic loss of body fluids containing proteins and electrolytes.

What does the loss of body fluids lead to in burns?

Dehydration and electrolyte imbalance and then renal failure and circulatory shock.

What are burns classified according to?

Their severity.

What is damaged in first-degree burns?

Only the pidermis.

What are some symptoms of first-degree burns?

Localized redness, swelling, and pain.

Which category does a sunburn fall into?

First-degree burn.

What is damaged in a second-degree burn?

The epidermis and the upper region of the dermis.

What are some symptoms of second-degree burns?

Localized redness, swelling, pain, and blistering.

When does skin regeneration occur in second-degree burns?

Within three to four weeks.

What are first and second-degree burns considered?

Partial thickness burns.

What are third degree burns considered?

Full-thickness burns.

What is damaged in third-degree burns?

The entire thickness of the skin.

How does the damaged area look in third-degree burns?

Gray0white, cherry red, or blackened, and initially there is little or no edema.

Burns are considered critical if these following conditions exist:

Over 25% of the body has second-degree burns

Over 10% of the body has third-degree burns

There are third-degree burns of the face, hands, or feet

In adults, what is used to estimate the percentage of body surface burned?

The rule of nines.

What is the rule of nines?

A method that divides the body into 11 areas, each accounting for 9% of the total body area, plus an additional area surrounding the genitals accounting for 1% of body surface area.

How many extra calories do patients with severe burns need? Why?

Thousands to replace lost proteins and allow tissue repair.

Since no one can eat enough food to provide the calories needed, what are burns patients given to provide these calories?

Supplementary nutrients thought gastric tubes and IV lines.

After the initial crisis has passed, what becomes the main threat?

Infection

After initial crisis has passed, what is the leading cause of death in burn victims?

Sepsis

What does longer-term treatment of full-thickness burns usually involve?

Skin graft

To prepare a burned area for a skin graft, what must happen?

The burned skin must be first debrided (removed).

What is the medical term for burned skin?

Eschar

What two processes can be taken in order to treat burn patients?

(1) Healthy skin is transplanted to the burned site. If possible, the skin is the patient’s, if not, immune system may reject.

(2) Synthetic skin can be applied to the debrided area. In time, the patient’s own dermal tissue absorbs and replaces the artificial one.

What is a major problem caused by skin grafting in burn patients?

The scar tissue that forms can often limit mobility at joints and other critical areas.