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Chapter 5. 1040 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?
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Chapter 5 1040 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