ch 3: physiology and histology of the skin

milady standard esthetics

Apocrine Glands

coiled structures attached to hair follicles found in the underarm and genital areas; secrete sweat

Arrector Pili Muscle

small, involuntary muscles in the base of the hair follicle that cause goose flesh when the appendage contracts; goosebumps

Barrier Function

protective barrier of the epidermis; the corneum and intercellular matrix protect the surface from irritation and dehydration

Bilayers

a thin polar membrane made of two layers of lipid molecules; these membranes are flat sheets that form a continuous barrier around all cells

Ceramides

glycolipid materials that are a natural part of the skin’s intercellular matrix and barrier function

Collagen

fibrous, connective tissue made from protein; found in the reticular layer of the dermis; gives skin firmness; topically, a long-chain molecular protein that lies on the top of the skin and binds water; derived from the placentas of cows

Couperose

redness; capillaries that have been damaged and are now larger, or distended blood vessels; commonly seen with telangiectasia

Corneocytes

another name for a stratum corneum cell; hardened, waterproof, protective keratinocytes; these “dead” protein cells are dried out and lack nuclei

Dermal Papillae

membranes of ridges and grooves that attach to the epidermis; contains nerve endings and supplies nourishment through capillaries to skin and follicles

Dermis

aka derma, corium, cutis, true skin; support layer of connective tissue, collagen, and elastin below the epidermis

Desmosomes

the structures that assist in golding cells together; intercellular connections made of proteins

Eccrine Glands

sweat glands found all over the body with openings on the skin’s surface through pores; not attached to hair follicles; secretions do not produce an offensive odor

Elastin

protein fiber found in the dermis; gives skin its elasticity and firmness

Epidermal Growth Factor (EGF)

stimulates cells to reproduce and heal

Epidermis

outermost layer of skin; a thin protective layer with many cells, mechanisms, and nerve endings; made up of five layers: stratum germinativum, st. spinosum, st. granulosum, st. lucidum, st. corneum

Eumelanin

a type of melanin that is dark brown to black in color; people with dark-colored skin produce mostly this type of melanin

Fibroblasts

cells that stimulate collagen production and amino acids that form proteins to aid in healing

Follicles

tubelike openings in the epidermis

Glycation

caused by an elevation in blood sugar, it’s the binding of a protein molecule to a glucose molecule resulting in the formation of damaged, nonfunctioning structures knows as advanced glycation end products (AGES). it alters protein structures and decreases biological activity

Glycosaminoglycans

large protein molecules and water-binding substances found between fibers of the dermis; GAGS are polysaccharide-protein and sugar complexes; work to maintain and support collagen and elastin in the cellular spaces, keeping protein fibers in balance

Hair Papillae

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

High-Energy Visible Light (HEV)

light emitting from electronic devices, reported to penetrate the skin more deeply than UV rays; damages collagen, hyaluronic acid, and elastin

Hyaluronic Acid

hydrating fluids found in the skin; hydrophilic agent with water-binding properties

Hydrolipidic Film

oil-water balance that protects the skin’s surface

Intercellular Matrix

lipid substances between corneum cells that protect the cells from water loss and irritation

Keratin

fibrous protein of cells that is also the principal component of skin, hair and nails; provides resiliency and protection

Keratinocytes

epidermal cells composed of keratin, lipids, and other proteins

Langerhans Immune Cells

guard cells of the immune system that sense unrecognized foreign invaders, such as bacteria, and then process these antigens for removal through the lymph system

Lamellar Granules

organelles secreted from keratinocytes, resulting. in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and required for correct skin barrier function. these bodies release components that are required for skin shedding in the stratum corneum

Leukocytes

white blood cells that have enzymes to digest and kill bacteria and parasites; also respond to allergies

Lymph Vessels

located in the dermis; supply nourishment within the skin and remove waste

Melanin

tiny grains of pigment that are produced by melanocytes and deposited into cells in the stratum germinativum layer of epidermis and in the papillary layer of dermis; a protein that determines hair, eye and skin color; produced as a defense mechanism to protect skin from the sun

Melanocytes

cells that produce skin pigment granules in the basal layer

Melanosomes

pigment carrying granules that produce melanin, a complex protein

Papillary Layer

top layer of the dermis; next to epidermis

Pheomelanin

a type of melanin that is red and yellow in color; people with light-colored skin produce more of this

Pores

tubelike opening for sweat glands on the epidermis

Reticular Layer

deeper layer of the dermis that supplies the skin with oxygen and nutrients; contains fat cells, blood vessels, sudoriferous glands, hair follicles, lymph vessels, arrector pili muscles, sebaceous glands, and nerve endings

Rosacea

chronic condition that appears primarily on the cheeks and nose and is characterized by flushing, telangiectasis, and in some cases, the formation of papules and pustules

Sebaceous Glands

aka oil glands; protect the surface of the skin; appendages connected to follicles

Sebum

oil that provides protection for the epidermis from external factors and lubricates both the skin and hair

Stratum Corneum

aka horny layer; outermost layer of the epidermis, composed of corneocytes

Stratum Germinativum

aka basal cell layer; active layer of the epidermis above the papillary layer of dermis; cell mitosis takes place here to produce new epidermal skin cellsS

Stratum Granulosum

aka granular layer; layer of epidermis composed of cells filled with keratin that resemble granules; replaces cells shed from the corneum

Stratum Lucidum

clear transparent later of the epidermis under the stratum corneum; thickest on the palms of hand and soles of feet

Stratum Spinosum

aka spiny layer; layer of epidermis above the st germinativum containing desmosomes, the intercellular connections made of proteins

Subcutaneous Layer / Hypodermis

subcutaneous adipose tissue located benSeath the dermis; protective cushion; energy storage for the body

Subcutaneous (adipose) Tissue

fatty tissue found below the dermis that gives smoothness and contour to the body, contains fat for use as energy, and also acts as a protective cushion for the outer skin

Sudoriferous (sweat) Glands

excrete perspiration, regulate body temperature, and detoxify the body by excreting excess salt and unwanted chemicals

T Cells

identify molecules that have foreign peptides; help regulate immune response

Telangiectasia

capillaries that have been damaged and are now larger, or distended, blood vessels; commonly called couperose skin

Transepidermal Water Loss (TEWL)

water loss caused by evaporation on the skin’s surface

Tyrosinase

the enzyme that stimulates melanocytes and thus produces melanin

UVA Radiation

aka aging rays; longer wavelengths ranging between 320-400 nm that penetrate deeper into the skin than UVB; cause genetic damage and cell death; contributes up to 95% of the sun’s UV radiationU

UVB Radiation

aka burning rays; wavelengths range between 290-320 nm; shorter, burning wavelengths that are stronger and more damaging than UVA; causes burning of the skin as well as tanning, skin aging, and cancer