Largest organ Protects and insulates Made of keratin (waterproofing)

1)Protects—holds fluids in, keeps disease causing organisms out 2)Melanin—pigment produced to protect from UV rays

3)Makes vitamin D from sunlight and a lipid called cholesterol 4)Nerve endings— sense heat, cold, pressure

The skin works with: Immune system—keeps pathogens out Excretory system—releases waste through sweating Nervous system—largest sensory organ

Epidermis-top layer, dead cells with tiny openings called pores Sebum-an oil, produced to keep skin soft and flexible

Dermis-thick layer, made up of collagen and produces melanin Contains nerve endings, blood vessels, and hair follicles

The sebaceous and sweat glands also reside in the dermis

Hair—made up of dead cells similar to the top layer of epidermis Nails—made up of solid plate of epidermal cells

Caused by a buildup of sebum under the skin and bacterial infections Squeezing pimples can cause the infection to spread/worsen

Clean Skin Sun protection Healthy diet

Sunburn Bruises Skin Cancer

Herpes Impetigo Acne

ARCH LOOP WHORL DOUBLE LOOPCENTRAL POCKET WHORL COMPOSITE