Skin- Largest organ in the body Two layers of skin
1-Epidermis- thin outer layer of skin. Cells are dead- continuously rubbed off by clothing, washing etc. You produce a whole new layer of skin every 28 days. Epidermis also produces the non living part of skin- hair and nails
2-Dermis- thick inner layer of skin. Contains blood vessels, nerve ending, and sweat and oil glands.
Below the dermis is the Subcutaneous Layer. This layer binds the skin to the body. This is where fat is stored
Skin performs 4 major functions
1-Protection- 1 st line of defense against disease. Holds moisture inside your body so tissue and organs do not dry out. Produces Melanin-pigment in the epidermis that gives skin color. Keeps out harmful UV rays in sunlight.
2-Sensation Receptor- Nerve ending that receives information from the environment and sends it to the brain. Receptors in skin sense cold, heat, contact, and pressure.
3-Temperature Regulation Body must stay between degrees F. Sweat glands and blood vessels in the dermis work together to maintain a normal temperature. Sweat glands produce perspiration to cool the skin Blood vessels in the skin dilate- this allows more blood to go to the surface to release the heat.
4- Waste Removal Our body takes in food, water, and air. The body uses these materials in building new cells. These produce waste products- they include salts, urea, and extra water- all are released through perspiration.
Sebaceous glands- structures within the skin that produce an oily secretion called sebum. found in the dermis
Sebum- An oil produced by the sebaceous glands. Keeps the skin from becoming dry
Pores- Tiny openings on the surface of the epidermis
Receptor- A nerve ending that receives or sends sensory information
Sun Protection Factor (SPF) - A number indicating the amount of protection provided against UV rays
Calculate Your Recommended SPF, or Sun Protection Factor, increases the length of time you can stay outside in the sun without incurring sunburn or irritation from UV-B rays. At present there is no standard to measure protection from UV-A rays.
Rate yourself: Select your skin type. The corresponding amount of time indicates how long you can stay safely in the sun before burning. Fair skin - 10 minutes Olive skin - 15 minutes Dark skin - 20 minutes
Look at the SPF on your sunscreen Note which SPF is stated on the product labeling, EXAMPLE- SPF 20 Calculate your protection time, the amount of time you can stay outside before burning: Multiply the sun safety time for your skin type with the SPF listed on your sunscreen. eg. 15 minutes (for olive skin) x SPF 20 = 300 minutes (5 hours) of sun protection Result: Olive skin using a sunscreen with SPF 20 can under ideal conditions stay in the sun for up to 5 hours.
Hair Follicles- sacs or cavities that surround the root of the hairs.