Chapter Integumentary

Skin ______ – superficial and thinner _____ – deeper and thicker ______ – areolar and adipose tissue –Not technically part of the skin –Aka subcutaneous layer –Contains nerves, blood and fat Function of fat

Epidermis _________________________ –Why? Layers –Stratum basale – deepest Single row of cuboidal or columnar All stem cells are here –Stratum spinosum Flatten and keratinize –Stratum granulosum Lipid water repellent More flat and more keratinized and beginning to die –Stratum corneum Dead cells

Layers Stratum ____________ –Shedding layer – help protect against injur and invasion

Dermis _________________ – why? Has nerves and blood to feed it and epidermis Sun exposure causes wrinkling by disrupting collagen and elastic fibers

Melanin In basal layer Same ________ of melanocytes in all people – skin color is based on melanin production Accumulations of melanin –Liver spots and freckles

Hair Fused dead keratinized cells –Keratin – tough protecting protein Hair follicles have ____________ –Hair stands on end Has _____________ (oil) Hair color – based on melanocytes –Gray – loss of melanin –Blond and red – more iron and sulfur in melanin Alopecia

Glands ____sweat glands – located over most of the body –Regulates body temp ____ sweat glands – armpit, groin, breast, beard –Begin function at puberty –Stimulated by stress and sex

Nails Hard, packed, keratinized epidermal cells Cuticle is stratum corneum ________ – white part due to thick stratum basale hiding vascular bed Nail matrix – gives rise to new nail

Skin function Temp regulation Protection Sensation Excretion and absorption (garlic) ______ synthesis –UV activates Vit D Helps absorp calcium and phosphorus from GI tract

ABCD for melanoma Asymmetry, border irregularity, color variegation, diameter >6mm. Red, white, blue with notched border and has a papule or nodule w/in 10% are missed w/ the ABCDs Incr rate of occurrence faster than any other cancer in US Ages 15-50yoa m/c 1:90 chance of developing melanoma Cancer of melanocytes Risk factors: sunlight, heredity, large # of nevi, large nevi