chapter 3 - skin structure and growth

arrector pili muscles

small, involuntary muscles in the base of the hair follicle that cause goosebumps

barrier function

complex of lipids that keep skin moist by preventing water evaporation and guards against irritants penetrating skin surface; help regulate skin's ph

broad spectrum sunscreen

sunscreen product that has been shown to protect from burning, skin cancer, and premature aging; protects against UVA and UVB radiation from sun

collagen

fibrous connective tissue made from protein; gives skin form and strength

dermal papillae

membranes of ridges and grooves that attach to epidermis

dermatologist

physician who specializes in disease and disorders of skin hair and nails

dermatology

medical branch of science that deals w study of skin and its nature, structure, functions, diseases, and treatment

dermis

aka derma, corium, cutis, or true skin; underlying or inner layer of skin

elastin

protein base similar to collagen that forms elastic tissue

dermal-epidermal junction

top of papillary layer where it joins epidermis

epidermis

outermost and thinnest layer of skin, made up of 5 layers; stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum

eumelanin

type of melanin that is dark brown to black in color

hair papillae

cone-shaped elevations at the base of the follicle that fit into hair bulb; papillae are filled w/ tissue that contains blood vessels and cells neccessary for hair growth and follicle nourishment

keratin

fibrous protein of cells that is also the principal component of skin, hair, and nails

melanin

tiny grains of pigment produced by melanocytes deposited into cells in stratum germinativum layer of epidermis and papillary layers of dermis

melanocytes

cells that produce dark skin pigment called melanin

motor nerves fibers

fibers of motor nerves that are distributed to arrector pili muscles attached to hair follicles; carry impulses from brain to muscles

papillary layer

outer layer of dermis, directly beneath the epidermis

pheomelanin

type of melanin that is red to yellow in color

reticular layer

deeper layer of dermis that supplies skin w oxygen and nutients

sebaceous glands

aka oil glands; glands connected to hair follicles; secrete sebum

sebum

fatty or oily secretion that lubricates skin and preserves softness of hair

secretory coil

coiled base of sudoriferous (sweat) gland

secretory nerve fibers

regulate excretion of perspiration from sweat glands and control the flow of sebum to surface of skin

sensory nerve fibers

fibers of sensory nerves that react to pain, pressure, temperature, and touch

stratum corneum

aka horny layer; outermost layer of epidermis

stratum germinativum

aka basal cell layer; deepest, live layer of epidermis that produces skin cells and is responsible for growth

stratum granulosum

aka granular layer; layer of epidermis composed of cells filled w keratin that resembles granules

stratum lucidum

clear, transparent layer of epidermis under stratum corneum

stratum spinosum

aka spiny layer; layer of epidermis above stratum germinativum (basal) layer

subcutaneous layer

aka hypodermis or superficial fascia; consists of subcutaneous (fat) tissue located beneath dermis

subcutaneous tissue

aka adipose or subcutis tissue; fatty tissue found below dermis that gives smoothness and contour to body; contains fats for energy, and acts as a protective cushion for skin

sudoriferous glands

aka sweat glands; excrete perspiration and detoxify body by excreting excess salt and unwanted chemicals

sweat glands

aka sudoriferous glands; excrete perspiration and detoxify body by excreting excess salt and unwanted chemicals

tactile corpuscles

small epidermal structures w nerve endings that are sensitive to touch and pressure