1. Covering and Protecting the Body The Integumentary System
Science 7

3. The Skin: A Cutaneous Membrane
Protects the body
Body covering
Maintains homeostasis
Regulates body temperature
Slows water loss
Houses sensory receptors
Excretes wastes
Absorbs UV radiation

4. Protective Body Covering

5. Old Skin Cells Go through Keratinization
What is keratinization?

6. Keratinization Definition: the hardening of older cells
Keratin protein fills cytoplasm
Keratin is tough and waterproof.
Tough layer of dead cells

7. Importance of Keratinization
Shields against water loss
Barrier for harmful chemical
Barrier for pathogens
Prevents physical injury of deeper tissue and organs

8. Regulates Body Temperature

9. Sweat Glands – 2 types Eccrine Apocrine Water & Electrolytes
More numerous
Apocrine
Water, Electrolytes, Protein & Lipids
Attached to hair

10. Eccrine Has sweat pore Helps release body heat
Activated when you are hot

11. Apocrine Connected to hair pore Becomes active at puberty
Activated by strong emotions
Excitement
Fear
Nervousness

12. Absorbs UV Radiation and Gives Skin its Color

13. How Do We Get Our Skin Color?

14. Epidermis Contains Melanocytes Produce melanin
Located in the deep epidermis
Melanin absorbs UV Radiation

15. Freckles
Localized concentrations of melanin

16. Skin Color Largely due to melanin Different Amount of melanin
Size of pigment granules
Additional factors:
Sunlight
X-ray exposure
Oxygen levels in blood vessels (pink / blue)