1. Integumentary System: pp. 861-864 Beginning Video http://www.youtube.com/watch?v=no_XRnoNGf E&feature=related http://www.youtube.com/watch?v=no_XRnoNGf E&feature=related Major structures: – Skin makes up about 15% of your total body weight – Nails derived from the epidermis – Hair derived from the epidermis

2. Integumentary System Key Functions Protects against injury, infection, and fluid loss Helps regulate body temperature

3. Skin Info Epidermis = outermost layer of the skin Dermis = functional layer of skin that lies just beneath the epidermis – Contains many nerve cells, blood vessels, hair follicles, and specialized skin cells Subcutaneous tissue = located beneath the skin just under the dermis; is a layer of connective tissues made mostly of fat, or adipose tissue

4. Skin Info Cont’d Keratin = a protein that makes skin tough and waterproof Cells get scraped, ripped, worn away by friction, and dried out because of moisture loss; your body deals with this damage by replacing these skin cells

5. Hair Info Hair follicles produce individual hairs (made mostly of dead, keratin-filled cells), which help protect and insulate the body – A shaft of hair grows up from the hair follicle and through the skin’s surface – Hair color is primarily determined by the presence of the pigment melanin (pigment that ranges in color from yellow to reddish brown to black and also has to do with skin color). Blonde hair and red hair typically contain less melanin than brown hair and black hair.

6. Nails Produced by specialized epidermal cells located in the light, semicircular areas at the base of each nails These cells become filled with keratin as they are pushed outward by new cells Protect the tips of the fingers and toes and continue to grow throughout life

7. What’s the deal with acne? Acne – a chronic inflammatory condition that involves the skin’s oil-producing glands – Oil glands in the dermis release sebum, an oily secretion that lubricates the skin; it’s released through ducts (pores) into nearby hair follicles Acne is caused by excessive secretion of sebum, which blocks pores with oil, dirt, and bacteria. As a result, the surrounding tissue becomes infected and inflamed, and the pores accumulate pus, producing pimples.

8. What about skin cancer? Skin cancer results from genetic mutations caused by overexposure to UV radiation You can reduce the risk of skin cancer by avoiding overexposure to either natural or artificial UV radiation and by using protective sunscreens

9. Play 3 Integumentary System Labeling Games http://wps.aw.com/bc_marieb_happlace_7_o a/0,11476,2807112-,00.html http://wps.aw.com/bc_marieb_happlace_7_o a/0,11476,2807112-,00.html – 1) Click on “Art Labeling: Skin Structure (fig.5.1, p.153)” link – 2) Click on “Art Labeling: Structure of a Hair Follicle (fig. 5.5, p. 161)” link – 3) Click on “Art Labeling: Structure of a Nail (fig. 5.6, p. 163)”