Skin Accessory Structures

Hair

dead keratinized cells, insulation and protection

Bulb

hair grows as a result of cellular division

Root

keratinization, embedded in skin, 3 layers of keratinized cells

Shaft

extends above skin, keratinization complete

Arrector pili

smooth muscle controlling hair; goosebumps

Medulla

central core

Cortex

flattened cells

Cuticle

outer layer of overlapping single cells

Nails

made of hard keratin, scale-like modification of epidermis

Nail Matrix

responsible for growth

Nail folds

skin overlapping border of the nail

Eponychium

nail fold that protects nail

Hyponychium

area under edge of plate that accumulates dirt

Eccrine sweat gland

temperature control, some antibacterial properties, exocytosis, skin surface, everywhere especially palms, soles, forehead

Apocrine sweat glands

sexual scent glands, exocytotsis, upper part of hair follicle, rarely skin surface, axillary and anogenital regions

Sebaceous glands

lubricate skin and hair, prevent water loss, antibacterial properties, holocrine, upper hair follicle, sometimes skin surface, everywhere except palms and soles

Holocrine

cell ruptures and disintegrates to release product