1. The Immune System Our Personal Army! Skin and the Immune System

2. What is the purpose of your skin? Protection-1 st line of defense against disease and bacteria

3. What are some properties of skin? Tough Durable Porous Elastic Flexible Responsive

4. Structure of Skin 1 st layer – Epidermis Outer Layer –outer, thin layer –composed of dead and living cells –25-30 layers of dead skin which sheds regularly REMEMBER THE DRY COMMERCIAL? Scratch your hand and spell out the word “dry” That is dead skin that flakes off! Dead skin cells contain keratin to waterproof the skin. Put a drop of water on your hand and watch it bead off.

5. Structure of Skin 2 nd layer – Epidermis Inner Layer –living cells –cells are constantly dividing and multiplying to replace dead cells –contains melanin to color skin and protect from solar radiation –fingerprints

6. EPIDERMIS

7. Why do we have fingerprints? Identification (specific to each person – coded for by DNA!) Ridges for gripping CAN YOU IMAGINE TRYING TO HOLD YOUR PENCIL WITH SLIPPERY GLOVES ON? THAT’S WHAT IT WOULD BE LIKE WITHOUT FINGERPRINTS!

8. Structure of Skin 3 rd Layer – Dermis –thick, innermost layer –used for padding and protection –blood vessels, nerves, sweat glands, and oil glands are located in the dermis –fat deposits add cushioning and are located in dermis –hair follicles are located in the dermis

9. DERMIS

10. Functions of Skin Protection Regulating body temperature (goosebumps/sweat) Sense organ for pain, pressure, temperature Maintains chemical balance

11. What happens when your skin gets injured? Small scrape – skin cells divide quickly and fill in gap Deep wound – bleeding occurs and there are further stages of healing that may include a scab and a scar; the cells divide to fill in the gap more slowly

12. What happens when your skin gets injured? Burns! –1 st degree – redness and death of epidermal cells –2 nd degree – blisters, scars, and damage of dermis –3 rd degree – skin function is lost, lots of scarring, epidermis and dermis are destroyed, skin grafts are necessary

13. Wounds…

14. What causes wrinkles? Age! –As you get older, your skin loses its natural elasticity and wrinkles form