INTEGUMENTARY SYSTEM

Structures of Integumentary system Skin Hair Nails Oil glands Sweat glands

Function of Integumentary system Functions: 1) physical barrier b/w the inside and outside of the body. 2)Contains nerve endings: sense, heat, pressure and pain. 3)maintain homeostasis by regulating temperature, retaining body fluids, and eliminating wastes

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. (More to come on this topic later….)

Hair, Nails, Oil & Sweat glands Hair reflects harmful UV rays. Nails protect sensitive nerve endings in fingertips. Oil glands keep skin supple and soft, capable of moving and stretching Sweat glands help us regulate our temperature.

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

Epidermal Layer:

Epidermal Layer Basal layer: deepest layer of epidermis, basal cells divide quickly and push older cells to the top where they die and slough off. (keeps us waterproof) Langerhans Cells: active in the capture, uptake & processing of antigens. (Fight off bad guys like bacteria)

Epidermal Layer Melanocytes: melanin producing cells found in epidermis. The pigment melanin is responsible for determining skin color. Merkle cells: Aid in the reception of light, gentle pressure sensations.

Epidermal Layer Skin Color: Product of the amount of melanin in the skin. (melanocytes make melanin, more melanin you make, the darker your skin) -- Dark enough to prevent UV damage to underlying cells, light enough to allow UV in 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.

Dermal Layer: blood vessels Skin controls heat loss via capillaries: When hot, capillaries will vasodilate to release heat from the blood stream and out of the body through the epidermis. When cold, capillaries will vasoconstrict to keep heat locked inside the body.

Collagen, elastin, keratin

Dermal Layer: proteins Collagen, elastin, keratin Keratin: fibrous protein; main structural component of hair and nails Collagen: structural component of connective tissue; scaffold for support and structure. Elastin: elastic protein that allows skin to return to its normal position after movement

Dermal Layer: 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.

Dermal layer: Glands Sebaceous Oil Glands produce sebum. -- - - associated hair follicle. Keeps skin soft, and hair from becoming brittle. Blackheads - accumulation of dried sebum. Whitehead- sebum trapped under layer of skin cells 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.