1. Muscular System

8. Hair Pore Epidermis Dermis Subcutaneous Erector Muscle Hair FollicleSweat Gland Fat Cells Capillary Nerve Ending

9. Integumentary System Skin – the body’s largest organ – 2 square meters Skin, and accessory organs (nails, hair, glands) make up the integumentary system

10. What does skin do? Most important function – protection Barrier against infection and injury Regulates body temperature Protection from UV radiation from sun

11. What does skin do? Gateway of sensations – heat, cold, pain, pressure Skin has 2 main layers: Epidermis – outermost layer Dermis – innermost layer

12. Epidermis Two layers –Outer epidermis – dead cells –Inner epidermis – living cells

13. Epidermis Inner layers go through rapid mitosis and push the older cells upwards They flatten, and make keratin (a protein) – waterproof, tough, flexible, contains melanocytes, (produce melanin – a pigment) no blood vessels

14. Dermis beneath epidermis Contains –blood vessels –nerve endings –sweat glands –sense organs –smooth muscles –hair follicles

15. Blood Vessels in Skin blood vessels in skin contract on cold days to conserve heat and widen on hot days to help with cooling the body What type of muscle controls that?

16. 2 types glands sweat and sebaceous glands sweat cools body sebum – oil – keeps epidermis flexible & waterproof