1. Bellringer: What is the largest organ of your body? What system is it part of? Write your answer down on a fresh sheet of paper or notetaking device!

2. http://www.youtube.com/watch?v=uH_uzjY 2bEE

3. Integumentary System Integument- “covering” Parts: – Skin – Sweat and oil glands – Hair – Nails

4. Functions?

5. Fun Facts Skin = 7% of your total body weight ~80% of dust in your home is dead skin cells More than 500 species of bacteria living on your skin 1.5-4 mm thick

6. 3 Main Layers

7. Epidermis Epi = upon Dermis = skin Tough but loosely anchored New cells created deep Mostly dead – “Beauty is only skin deep” ?! 5 layers

9. 4 Important Cells: Keratinocytes – Produce protein keratin which gives skin protective qualities Melanocytes – Produce melanin (nucleus umbrellas!) Langerhans – Phagocytes Merkel cells – Sensory cell

10. Stratum Basale “Basal Layer” Deepest Produces keratinocytes Mitosis hotspots Merkel hangout

12. Stratum Spinosum “Prickly Layer” Funny shaped keratinocytes Langerhan hangout Tension-resisting

14. Stratum Granulosum “Granular Layer” 3-5 cell layers thick Waterproofing Cell death line

16. Stratum Lucidum “Clear Layer” Only in thick skin Just a few rows of dead keratinocytes

18. Stratum Corneum “Horny Layer” 20-30 dead cells thick 75% of epithelial thickness Protects against abrasion and penetration FULL OF HORNY CELLS (they’re shaped like horns)

19. Activities! Color the different layers of the epithelium Draw pictures of each cell type and epithelial layer using a microscope