Sponge: Set up Cornell Notes on pg. 53 Topic: 6.6 Healing of Skin Essential Question :

1. 6.6 Healing of Skin 2.1 Atoms, Ions, and Molecules Sponge: Set up Cornell Notes on pg. 53 Topic: 6.6 Healing of Skin Essential Question: • What is the tissue response to inflammation? • Which type of burn is most likely to leave a scar? • What is the tissue response to inflammation? • Which type of burn is most likely to leave a scar?

2. Healing of Wounds • Inflammation: Normal response to injury/stress • Blood vessels in affected tissues dilate • Allows fluids to leak into the damaged tissue • Inflamed skin becomes reddened, swollen, warm, and painful to the touch • Painful, but provides the tissue with more nutrients and oxygen to aide in healing

4. Inflammation Video

5. Healing of Cuts: • Shallow epithelial cells divide more rapidly and fill in the injury site • If a cut extends into the dermis and/or subcutaneous layers the blood vessels break and the escaping blood forms a clot in the wound • Scab is formed • Covers and protects • Fibroblasts migrate into the injured region and form collagenous fibers that bind the edges of the wound together • Connective tissue matrix releases “growth factors” that stimulate certain cells to divide • Blood vessels extend into the area beneath the scab • Phagocytes remove dead cells/debris • Eventually scab sloughs off • If wound is extensive may get a scar • Scars are largely composed of collagenous fibers

7. Healing of Burns • Deep • Partial -Thickness Superficial Partial -Thickness • Full- Thickness • 4th Degree

8. Healing of Burns • Superficial partial-thickness (1st degree) burn: • Injures only the epidermis • warm/reddened skin • Dermal blood vessels dilate • In time layer may shed • No scarring • Healing: few days-2 weeks • Cause: slightly burned or sunburned • Painful

9. Deep partial-thickness (2nd degree) burn: • Destroys some epidermis as well as some of the underlying dermis • Blisters appear as fluid escapes from damaged dermal capillaries • moist and firm • Varies in color • Over time epithelial cells divide • Usually completely recover • No scarring unless infection occurs • Healing: depends on accessory structures (hair follicles/sweat glands/sebaceous glands) 2-3 wks • Causes: Exposure to hot objects, hot liquids, flames, or burning clothing • Painful

11. Full-thickness (3rd degree) burns: • Destroys epidermis, dermis, AND accessory structures • Skin becomes dry and leathery • Can be any color from black to white • Since the epithelial cells are destroyed, healing can only occur from epithelial cells by growing inward • If extensive, skin graft needed • Healing: depends on extent • Causes: “immersion” in hot liquids, prolonged exposure to hot objects and/or chemicals • Painless

13. 4th degree burns- epidermis, dermis, subcutaneous layer and into underlying muscle and bone • Black color (charred) • Dry • Painless • Can lead to amputation, significant impairment, possible death

14. Burn Classification and Treatment Video • Special Report: Inside Top Burn Treatment Center

15. Pg. 52 Skin Graft Video Notes

16. Skin graft: • Autograft: skin transplant from your own body • Homograft: from one person to another person • Comes from cadavers • Works by covering wounds • Shrink wound • Prevents infections • Preserves deeper tissues • Will leave extensive scars

17. Rule of “nines”: Doctors must estimate the extent of a body’s surface that is affected • Divide the body into % of 9 or multiples of 9s • Important in planning to replace body fluids and electrolytes and for covering the burned area with skin or skin substitutes

18. Skin Graft: How Its Made • Skin Graft