Skin (cont.), Hair, Nails

Sweat pore

the tiny surface opening of a sweat gland duct through which sweat is excreted onto the skin

Eccrine gland

secretes watery sweat for thermoregulation all over the body

Apocrine gland

sweat gland located in axillary and anogenital areas that secretes a viscous, odor-producing fluid into hair follicles

Sebaceous gland

connected to hair follicles that secretes oily serum to lubricate skin and hair

Ceruminous gland

modified apocrine sweat gland in the ear canal that produces earwax (cerumen)

Sensory nerve

nerve fiber that transmits sensory signals from the skin to the CNS

Free nerve ending

unspecialized nerve endings in the epidermis and dermis that detect pain and temperature changes

Tactile corpuscle/Meissner’s corpuscle

encapsulated sensory receptor in the papillary dermis sensitive to light touch and low-frequency vibration

Lamellar corpuscle/Pacinian corpuscle

layered sensory receptor deep in the dermis/hypodermis sensitive to deep pressure and high-frequency vibration

Hair shaft

portion of the hair that projects above the skin surface

Hair root

portion of the hair embedded beneath the skin surface

Hair follicle

tubular epithelial sheath that surrounds and produces the hair root

Hair bulb

expanded, bulbous base of the hair follicle containing dividing cells

Papilla of hair

vascular connective tissue projection extending into the base of the hair bulb to supply nutrients

Hair matrix

layer of actively dividing germinal stem cells inside the hair bulb that produces the hair shaft

Arrector muscle of the hair/Arrector pili

smooth muscle attached to the hair follicle that contracts to pull the hair upright (goosebumps)

Hair root plexus

network of sensory nerve endings surround the hair follicle that detects hair movements

Adipose tissue

fat-storing connective tissue in the hypodermis that provides insulation, cushioning, and energy storage

Cutaneous vascular plexus

deep vascular network located at the boundary between the dermis and hypodermis

Papillary vascular plexus

superficial network of blood vessels located directly beneath the dermal papillae

Capillary loops

microscopic loops of blood vessels within the dermal papillae that nourish the epidermis

Nail plate

hard, exposed outer body of the nail composed of densely packed dead keratinized cells

Nail root

hidden proximal portion of the nail embedded beneath the fold of skin at the base

Free edge

the distal extension of the nail plate that overhands past the fingertip or toe

Nail matrix

actively dividing epithelial tissue at the proximal end under the nail root responsible for nail growth

Nail bed

layer of vascular epidermal tissue beneath the nail plate upon which the nail rests

Lunule

pale, crescent-shaped area at the proximal base of the nail plate overlying the thick nail matrix

Eponychium/Cuticle

narrow fold of stratum corneum skin extending onto the base of the nail plate

Hyponychium

thickened region of stratum corneum beneath the free edge of the nail plate