5 Epidermal Layers - Blisters, Calluses &Psoriasis Composed primarily of keratinized stratified squamousepithelial cells -- consisting of 4-5 layers:stratum corneum: outermost layer, keratinized dead epitheliumstratum lucidum: layer found in thickest areas of skinstratum granulosum: 3-5 layers of flattened granular cells, developing keratin fibersstratum spinosum: multiple layers of cellsstratum basale: deepest layer of single cuboidal or columnar cells, also contains melanocytes- Blisters, Calluses &Psoriasis
6 Melanocytes Specialized cells in epidermis produce melanin dark pigment providing skin colorcells lie in stratum basalecytocrine secretions: cellular extensionabsorbs UV radiation in sunlightprotects dermis
7 Skin Color - Genetics, Environment & Physiology: # of melanocytes - difference in kind, amount & sizesunlight, UV light, etc.blood in dermis, blood vessels, freckles & molesother pigments - carotinoidsjaundice – liver disorder
14 Nails: Protect Ends of Fingers & Toes Specialized epithelial cells that keratinize; consist of nail plate & nail bedLunula (1/2 moon shape region): active growing area of nailWhat can nail appearance indicate?
15 Skin Glands Sweat glands: Sebaceous glands: - assoc. w/ hair follicles,secrete sebum - oils hair,lubricates skin & preventwater loss- acne vulgarisSweat glands:Eccrine: deep in dermis or subcutaneous layer, odorless secretions, function in thermoregulationApocrine: found near hair follicles, in axillary regions, released during pain, fear & stress or sexual arousal- Ceruminous & mammary glands
18 Temperature Regulation Homeostatic mechanism- receptor- control center- effectors
19 Body Temperatures Under Varying Conditions heat exhaustionheat strokefeverhypothermia
20 Wounds & Healing Inflammation: normal response to injury or stress Laceration: break in the skinepidermal cut: epithelial cells around injury proliferate & newly formed cells fill indermal cut: clot forms (RBC, platelets, proteins)growth factors: induce migration of fibroblast & macrophagessmooth muscle & fibroblasts stimulate tissue repair