Ch. 6 Section 3 Skin

1. Ch. 6 Section 3 Skin Michelle Napier

2. the largest organ of our body • made up of 3 basic layers 1. skin 2. layers of skin epidermis- outermost layer dermis- middle layer fatty layer- innermost layer

3. cells are dead and water repellant • new cells are produced constantly at the base of the epidermis • produces melanin 3. epidermis • pigment that protects skin and gives it its color • this is what makes tanning possible 4. melanin

4. 5. dermis • thicker than the epidermis • contains blood vessels, nerves, muscles, oil, and sweat glands • holds fat

5. protection • sensory response • vitamin D formation- helps blood absorb calcium • regulates body temperature • helps the body get rid of waste 6. functions of the skin

6. 7. heat and waste exchange • blood vessels in the skin expand and dilate which releases heat or holds heat in • as they expand, blood flow increases and heat is released • our skin holds about 3 million sweat glands

7. regulate body temperature • release waste • when vessels dilate, pores on the skin open and perspiration is released from sweat glands. This allows your body to cool off. • cells use energy and nutrients and have waste which is released through sweat 8. functions of sweat glands

8. 9. bruises • blood vessels under the skin burst but skin stays in tact • red blood cells leak into tissues and a chemical called hemoglobin is released • hemoglobin is responsible for the different colors of bruises

9. a tear in the skin • scars are formed when large amounts of tissue build up under a cut 10. cut 11. skin grafts - pieces of skin cut from one part of the body and put on another part that was injured or burned