1. The Integumentary System

2. Skin, Hair and Nails Now using the microscopes. Examine your skin, hair and nails. In your spiral, diagram what you see.

3. Organs of the integumentary system skin hair nails The name is derived from the Latin integumentum, which means “a covering.”

4. Label and color the parts of the integumentary system finger nail

5. Skin The largest organ in your body Functions  Covers the body and prevents water loss  Protects the body from injury and infection  Regulates body temperature  Eliminates wastes (sweat)  Produces vitamin D  Gathers information about the environment  Stores fat for fuel and insulation

6. Prevents Water Loss Skin prevents water from leaking out of your body

7. Prevents Infection Skins acts as a barrier to bacteria and viruses

8. Maintains Homeostasis Helps to keep the body temperature normal Has blood vessels that tell the body when it is hot or cold  Hot – blood vessels get larger and sweating occurs  Cold – blood vessels constrict to keep blood in the body’s core

9. Eliminates Waste Sweating eliminates dissolved waste from your body

10. Gathers Information Skin contains nerves that can feel pain or pressure

11. Provide Vitamin D With the help of sunlight, your skin produces vitamin D Vitamin D is essential in calcium absorption from food

12. Layers of Skin Skin consists of three main layers  epidermis  dermis  subcutaneous layer subcutaneous layer

13. Epidermis Outermost layer 30-60 cells thick No nerves or blood vessels Top layer is dead New cells formed at the bottom of this layer Skin cells shed every 2 weeks Where nails grow Contains melanin

14. Epidermis Where nails grow Contains melanin Every minute, 30,000 - 40,000 skin cells fall off 95% of your skin cells make new cells 5% make melanin More sun exposure = more melanin (tan)

15. Dermis Middle layer Contains nerves and blood vessels Contains sweat glands, oil glands and hair follicles Contains collagen and elastin that allows skin to stretch

16. subcutaneous layer Made mostly of fat Keeps you warm Absorbs shock Attaches your skin to the underlying tissue

17. hair Made of a strong, dead protein, called keratin Grows out of a tiny tube called a follicle Hair growth is caused by rapid mitosis in the follicle Hair follicles are everywhere except  lips  palms  soles

18. hair Over 100,000 follicles on the scalp Each follicle is attached to a gland that secretes sebum (oil) Color is partially determined by melanin

19. nails Modified hair that grows from your cuticle Made of keratin No nerve endings Protects the end of fingers and toes Takes 6 months to grow from cuticle to tip

20. nails Fingernails grow faster than toenails Nails grow faster on your dominant hand Nails DO NOT grow after death

21. Body systems that work with the integumentary system; respiratory system to get oxygen and remove carbon dioxide circulatory system to deliver oxygen excretory system to eliminate waste