Skin and Its Appendages – General Human Anatomy I

Vocabulary flashcards covering skin layers, cells, appendages, glands, hair, and nail anatomy as presented in the lecture notes.

Epidermis

Outer layer of skin made of keratinized stratified squamous epithelium.

Dermis

Thick middle layer of skin composed of dense collagen and elastic connective tissue; contains dermal papillae.

Hypodermis (Subcutaneous Tissue)

Loose connective tissue anchoring skin to underlying muscle and bone; stores about half of the body’s fat.

Functions of the Skin

Protection, sensation, vitamin D production, temperature regulation, and excretion.

Keratinocyte

Primary epidermal cell (≈90 %) that produces keratin for waterproofing and protection.

Langerhans Cell

Immune cell of the epidermis that helps protect against pathogens.

Melanocyte

Pigment-producing cell of the epidermis that synthesizes melanin.

Merkel Cell

Sensory receptor cell in the epidermis associated with touch perception.

Stratum Corneum

Outermost epidermal layer of dead, flattened, keratin-filled cells.

Stratum Lucidum

Clear epidermal layer found only in thick skin (palms, soles).

Stratum Granulosum

Epidermal layer where keratinocytes begin keratin aggregation and cell death.

Stratum Spinosum

Epidermal layer with spiny-appearing keratinocytes connected by desmosomes.

Stratum Basale

Deepest epidermal layer where mitosis produces new keratinocytes; source of hair matrix cells.

Dermal Papillae

Upward projections of dermis that supply the epidermis with blood and create fingerprints/footprints.

Arrector Pili Muscle

Smooth muscle that elevates hair to 90° causing goosebumps in response to cold or stress.

Glabrous Skin

Hair-free skin found on palms, soles, lips, and certain genital regions.

Hair Shaft

Portion of hair projecting above the skin surface.

Hair Root

Portion of hair located within the dermis and surrounded by the hair follicle.

Hair Follicle

Epithelial sheath surrounding the hair root and bulb.

Hair Bulb

Enlarged base of the hair follicle containing the hair papilla.

Hair Papilla

Connective-tissue projection with blood vessels that nourish the hair matrix.

Hair Matrix

Mitotically active cells derived from stratum basale that generate new hair cells.

Medulla (Hair)

Central core of hair containing soft keratin and air spaces.

Cortex (Hair)

Middle layer of hair providing strength and containing pigment granules for color.

Cuticle (Hair)

Outermost shingle-like layer of flattened, keratinized cells; splitting causes split ends.

Sudoriferous Gland

Sweat gland important in thermoregulation and excretion.

Eccrine Gland

Most common sweat gland releasing watery sweat directly onto skin surface.

Apocrine Gland

Sweat gland in axilla, genital, and areolar areas producing viscous secretion that becomes odorous when bacterial decomposed.

Ceruminous Gland

Modified sweat gland in ear canal producing earwax (cerumen).

Mammary Gland

Modified sweat gland specialized for milk production.

Sebaceous Gland

Oil gland that secretes sebum into hair follicles to lubricate skin and hair.

Nail Plate

Hard, translucent keratin structure visible as the nail.

Lunula

Crescent-shaped whitish area at the nail base representing visible part of the matrix.

Nail Root

Proximal portion of nail hidden under skin fold; lies within the nail sinus.

Nail Matrix

Germinal tissue beneath nail that produces new nail cells.

Nail Bed (Hyponychium)

Epithelium beneath nail plate at fingertip; secures nail to digit and forms protective seal.

Free Margin

Distal edge of nail plate used for cutting or abrasion.

Cuticle (Eponychium)

Thickened epithelial tissue along proximal nail border protecting the matrix.