Muscular System

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

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

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

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

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

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

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

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?

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