CHAPTER 33.3 INTEGUMENTARY SYSTEM

Structure and Function the skin as well as hair, nails, oil glands, and sweat glands. Functions: 1) physical barrier b/w the inside and outside of the body. (Langerhans cells) 2)Contains nerve endings: sense, heat, pressure and pain. 3)maintain homeostasis by regulating temperature, retaining body fluids, and eliminating wastes

Layers of Skin Epidermis-outermost, made of mostly dead keratinized cells. Dermis- middle layer- nerves, oil and sweat glands, capillaries. Subcutaneous Fat- fat as insulation, blood supply

Skin largest organ of the body Varies in thickness from 1/50 inch (0.5 mm) in the eyelids to 1/4 inch (6.3 mm) in the soles of the feet Changes in the skin often indicate the presence of other body system disorders including anemia, respiratory disorders, liver disorders, cancer, and shock.

Skin Color product of the amount of melanin (brown pigment) in the skin and the skin’s blood supply. Melanocytes Dark enough to prevent UV damage to underlying cells, light enough to allow UV to produce Vitamin D.

Skin color map (indigenous people) Skin color map (indigenous people). The twin role played by the skin- protection from excessive UV radiation and absorption of enough sunlight to trigger the production of vitamin D – means that people living in the lower latitudes, close to the Equator, with intense UV radiation, have developed darker skin to protect them from the damaging effects of UV radiation. In contrast, those living in the higher latitudes, closer to the Poles, have developed fair skin to maximize vitamin D production.

Albinism A genetic mutation that causes an animal not to produce any melanin or other pigments. Dangerous because skin is exposed to UV radiation. Nystagmus and Photophobia of the eye are common.

Skin Controls Heat Loss Capillaries : when warm will vasodialate to release heat from the body. When cool will vasoconstrict to keep heat inside the body.

Collagen, elastin, keratin

Sweat Glands Eccrine Sweat glands are all over the skin to release water, salts, and urea. Help to cool the body. Appocrine sweat glands are in the armpits and groin. They produce a thick milky protein-based sweat that has an odor.

Oil Glands Sebaceous Oil Glands produce sebum. -- - - associated hair follicle. Keeps skin soft, and hair from becoming brittle. Blackheads - accumulation of dried sebum. Acne, active bacterial infection of the oil glands.

Skin Cancer Wear sunscreen: SPF 15 or greater Notice moles… that change that are larger than a pencil eraser that have jagged edges

Burns The Rule of Nines is used to estimate the amount of skin that has A burn that affects only the epidermis is “1st degree” and will generally heal in 5-7 days. The epidermis and dermis is “2nd degree.” All three layers is “3rd degree.” been burned. Skin grafts may be necessary to quickly cover burned skin so it does not become infected.