1. The Integumentary System
Skin, Hair & Nails

2. The System Skin, hair and nails make up the integumentary system
These structures are made of a protein called keratin.

3. The Skin The largest organ of the body
Integument means “skin” and comes from the Latin word meaning “to cover”

4. 2 Layers of the Skin 1. Epidermis
Outer layer of the skin made of dead cells
Shed every 4-5 weeks
Contains no blood vessels
Pores allow sweat and oil to escape
Contains melanocytes which make dark skin pigment melanin

5. 2 Layers of the Skin

6. 2 Layers of the Skin 2. Dermis
Inner layer of skin, lies beneath the epidermis
Contains blood vessels, nerve endings, glands, sensory receptors, & hair follicles

7. Glands found in the Dermis
Sweat glands
Produce sweat when your temperature rises too high or when under stress
Sweat contains salts, water, and other compounds
Sweat helps rid the blood of wastes
Sebaceous glands
Produce an oily secretion called sebum
Sebum spreads along the surface of the skin keeping it flexible and waterproof

8. Below the Skin
Region below the dermis is called hypodermis or subcutaneous tissue
Fatty tissue which stores fat and anchors skin

9. Functions of Skin Barrier against infection and injury
Regulates body temperature
Removes waste products
Protection against UV rays from the sun
Sensory receptor for pressure, heat, cold & pain

10. Temperature Regulation
When it’s cold, the blood vessels in the dermis will contract, limiting heat loss.
On hot days, blood vessels will dilate (widen) bringing the heat from the body’s core to the surface to be released.
Sweat released from glands evaporates to cool the skin.

11. Barrier against pathogens
Regulates temperature
Protects against UV rays
Removes wastes

12. Hair Covers almost every exposed surface of the body
Hair protects the skin from UV rays and insulates when cold by standing up (arrector pili muscle)
Hair in the nostrils, ears, and eyelashes helps prevent dirt and
pathogens from entering the
body.

13. Nails Protect fingertips and help in picking up small objects
Correspond to hooves and claws in other mammals.

14. Skin Cancer Associated with exposure to sun (UV rays)
Melanoma is the deadliest type; uncontrolled growth of melanocytes.

15. Pore
Epidermis
Sebaceous gland
Melanocytes
Sweat gland
Dermis
Hair
follicle
Arrector pili muscle
Blood vessels
Nerve ending
Hypodermis