1. 6th Grade Science Integumentary System

2. I. General Size 1. Largest organ 2. 7% of body weight B. Function 1. Protection from injury 2. Protection from infection 3. Protection from water loss 4. Control body temperature 5. Remove waste 6. Gather information about the world 7. Activation of Vitamin D

3. C. Layers Epidermis (Keratinocytes) i. Outer layers ii. No blood or nerves iii. Cells die and are replaced every two weeks iv. Constant outward flow protects from bacteria v. Layers prevent water loss vi. Produces melanin (protect from UV damage)

5. 2. Dermis i. Many blood vessels and nerves ii. Sweat glands – Cool body iii. Oil glands a. Hair and skin health b. Chemical signals iv. Hair

6. D. Special Structures 1. Nails

7. 2. Hair i. ArrectorPili Muscle (Fright or cold)

8. II. Injuries A. Classified by severity 1. First degree burn – only epidermis is damaged 2. Second degree burn – upper part of dermis i. Blisters appear ii. Skin heals with scarring 3. Third degree burn – consume thickness of skin i. Burned area appears white, red, or blackened ii. Often little pain noticed as nerves are all dead

9. III. Diseases Cancer (sun exposure) 1. Basal cell carcinoma – most common 2. Squamouscell carcinoma 3. Melanoma –Most dangerous type B. Age spots C. Smoke damage