The Skin

1. The Skin • Homeostatic Imbalances

2. Tattoos • Needle is used to deposit pigment within the dermis • Risks: • One ugly tattoo • Dyes w/cancer causing agents • Hepatitis C • Removal: • Dermabrasion, cryosurgery, caustic chemicals, laser based technology

3. Excessive Sun exposure • Damages skin • Elastic fibers clump -> leathery skin • Chance for herpes (aka cold sore) increases • Alter DNA of skin cells -> skin cancer • inc melanin in black ppl dec chance for skin cancer

4. Decubitus Ulcer • Restriction of normal blood supply to skin • Causes cell death • Occurs often in bedridden patients who are no turned regularly or who are dragged or pulled repeatedly across bed • Blood supply restricted -> blanching • Skin reddens when pressure released • Cracks appear in skin @ compressed • areas

5. Infections and Allergies • Athlete’s Foot • Itchy, red, peeling • between toes • Fungal infection: fungus grows on or in the top layer of the skin • Easily transferred • Can be caught walking near swimming pools and lockers

6. Infections and Allergies • Boils and carbuncles • Boils: inflammation of hair follicles and sebaceous glands • Carbuncles: boils caused by bacterial infection

7. Infections and Allergies • Cold Sores • Small, fluid-filled blisters • Itch and sting • Caused by herpes simplex infection • Virus localizes in cutaneous nerve • Dormant until activated by emotional upset, fever, or UV

8. Infections and Allergies • Contact dermatitis • Itching, redness, swelling of skin, blistering • Caused by exposure of skin to chemicals • i.e. poison ivy

9. Infections and Allergies • Impetigo • Pink, water-filled, raised lesions • Develops yellow crust and ruptures • Caused by staphylococcus infection • Common in elementary children

10. Infections and Allergies • Psoriasis • Reddened epidermal lesion • Dry, silvery scales • May be disfiguring

11. Burns • Tissue damage and cell death caused by intense heat, electricity, UV, or chemicals • Two life-threatening problems: • Body loses supply of fluids containing proteins and electrolytes • Dehydration and electrolyte loss = shutdown of kidneys and circulatory shock • Lost fluids must be replaced immediately!

12. Burns • Rule of nines: • Divides body into 11 area, each accounting for 9% of total body surface (plus 1% for genital) • Infection leading cause of death in burn victims • Burned skin sterile for 24 hours • Patient’s immune system depressed

13. Burns • First degree • Only epidermis damaged • Area red and swollen • Not serious • Heals in two to three days • i.e. sunburn

14. Burns • Second degree • Injury to epidermis and upper dermis • Red, painful, and blisters present • Enough epithelial present for regeneration • No permanent scars result if taken care of • First and second degree burns are called partial-thickness burns

15. Burns • Third degree • Destroys entire thickness of skin • aka full-thickness burn • Burned area is blanched or blackened • Nerve endings destroyed = no pain • Regeneration not painful • Skin grafting

16. Fourth Degree Burn • a burn that extends deeply into the subcutaneous tissue, completely destroying the skin, subcutaneous tendons, underlying tendons, involving muscle, fascia, or bone

17. Burns • Considered critical if: • 25% has second degree burns • 10% has third degree burns • Third degree burns of face, hands, or feet • Dangerous because burned respiratory passageways • Swells and causes suffocation

19. Skin Cancer • Single most common type of cancer in humans • Most important risk factor is UV radiation

20. Skin Cancer • Basal cell carcinoma • Least malignant • Most common type (usu. On face) • Cells in stratum basale cannot form keratin and no longer honors boundary between epidermis and dermis • Appears shiny, dome-shaped nodules that develop an ulcer • Slow-growing • curable

21. Skin Cancer • Squamous Cell Carcinoma • Lesion appears scaly, reddened papules • Gradually forms ulcer • Usu on scalp, ears, dorsum of hands, lower lip • Grows rapidly and into lymph nodes if not removed • Curable surgically or w/radiation therapy

22. Skin Cancer • Malignant melanoma • Cancer of melanocytes • Accounts for 5% of skin cancers • Usu. Appears as spreading brown to black patch • Grows into lymph and blood vessels • Survival is 50% • Treatment is wide surgical excision with immunotherapy

23. Malignant melanoma • Use ABCD on new moles or pigmented spots to recognize • Asymmetry: two sides of spot do not match • Border irregularity: borders of lesion are not smooth and have indentations • Color: spot contains areas of different colors • Diameter: spot is larger than 6 mm in diameter

24. AGE • Newborn: skin is thin and blood vessels are visible • Skin thickens with age • Adolescence: skin and hair become oily • Adulthood (twenties and thirties): skin reaches optimal appearance • Environmental affects: abrasion, chemicals, wind, sun, and other irritants clog pores with pollutants and bacteria • dermatitis (skin inflammation), pimples, scales occur

25. Old Age: subcutaneous tissue decreases, skin is drier, skin thins, decreased elasticity • FRECKLES: Concentration of Melanin in a certain area • HAIR: • By 50, # of follicles dec by 1/3 • Bald men have hair in “bald areas” • degenerated follicles develop colorless and tiny hair • Graying: dec in amount of melanin deposited in the hair • emotional crisis, anxiety, protein deficiency, chemotherapy, radiation, excessive vitamin A, fungal diseases, genetics