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SKIN!. SKIN – Your epidermis is showing!. The skin is the largest organ in the human body We gain a lot of information from the environment outside of our bodies by sensing through our skin Has two layers of tissue: Epidermis Dermis. EPIDERMIS. Top layer of skin tissue
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SKIN – Your epidermis is showing! • The skin is the largest organ in the human body • We gain a lot of information from the environment outside of our bodies by sensing through our skin • Has two layers of tissue: • Epidermis • Dermis
EPIDERMIS • Top layer of skin tissue • Cells on the top of this layer are dead • they rub off every time you scratch any part of your skin • New cells are produced at the bottom of the epidermis layer • Cells in the epidermis produce a chemical called melanin • Melanin gives color to the skin • more melanin = darker color
DERMIS • Layer of tissue under the epidermis • Much thicker than the epidermis and contains the blood vessels, nerves, oil and sweat glands • 3 million sweat glands!
What is the purpose and function of skin? There are 5 functions for your skin: • Protection • against disease, keeps water in • Senses • senses what is going on around the body • Helps control body temperature • sweating • Excretion (removal) of wastes • sweating • Vitamin D • Is created in epidermis with the ultraviolet light from the Sun • Helps your body absorb calcium which is important for skeletal system!
Injuries • Injuries to your skin like: • Scratching • Burning • Ripping • These injuries may remove the epidermis layer and new cells may not be created • This will make it easier for bacteria and viruses to enter your body, and an infection may occur
Activity: 1) On a piece of paper in your lab section, write down 3 observations about the epidermis on your hands 2) One volunteer for each group will place a small plastic bag over his/her hand and another group member will use tape to keep the bag closed 3) Start working on your worksheet for today and after 5-6 minutes and look at the hand with the bag. Please answer the following questions under your initial observations: 4) Questions: What formed inside the bag? Where did this substance come from? Why is it necessary for this substance to form, even though you are inactive (for example not jumping around in P.E. class)