Integumentary System Vocabulary

Vocabulary practice flashcards defining key structures, layers, glands, functions, and pathological conditions of the integumentary system based on lecture notes.

Mucous Membranes

Epithelial membranes that line body cavities opening to the exterior, composed of a moist epithelium resting on top of lamina propria.

Serous Membranes

Double-layered membranes lining internal body cavities closed to the outside world, including the pleura, pericardium, and peritoneum.

Parietal Layer

The outer lining layer of a closed body cavity formed by a serous membrane.

Visceral Layer

The inner layer of a serous membrane that directly wraps around an organ.

Cutaneous Membrane

The dry outer covering of the body (the skin), composed of keratinized stratified squamous epithelium overlying dense fibrous connective tissue.

Synovial Membranes

Connective tissue membranes containing no epithelial cells that enclose joint capsules, tendon sheaths, and bursae to produce lubricating synovial fluid.

Epidermis

The superficial, avascular skin layer composed of keratinized stratified squamous epithelium.

Dermis

The deep, vascular layer of skin located beneath the epidermis, made of areolar and dense irregular connective tissue containing elastic and collagen fibers.

Hypodermis

The subcutaneous layer deep to the dermis composed of adipose tissue that serves as insulation, energy storage, and attachment to underlying muscles.

Stratum Basale

The deepest layer of the epidermis attached to the basement membrane where rapid mitosis takes place; contains keratinocytes, melanocytes, and Merkel cells.

Stratum Spinosum

An epidermal layer 8–10 cells thick containing keratinocytes and Langerhans cells (epidermal dendritic cells) that trigger immune responses.

Stratum Granulosum

A thin epidermal layer where dying keratinocytes flatten, accumulate keratin granules, disintegrate organelles, and form a water-resistant barrier.

Stratum Lucidum

A clear epidermal layer found only in the thick skin of the palms of the hands and soles of the feet.

Stratum Corneum

The outermost layer of the epidermis consisting of 20–30 layers of dead, flattened, fully keratinized, anucleate cells that continually flake off.

Papillary Layer

The superficial fifth of the dermis composed mainly of areolar connective tissue with dermal papillae, capillaries, sensory receptors, and bare nerve endings.

Reticular Layer

The deeper four-fifths of the dermis consisting predominantly of dense irregular connective tissue packed with collagen fibers.

Eccrine Glands

Abundant sweat glands distributed over most of the body that secrete a watery fluid containing salts, urea, uric acid, and vitamin C to regulate body temperature.

Apocrine Glands

Sweat glands located in the axillae and groin that empty a fatty acid- and protein-rich milky secretion into hair follicles starting at puberty.

Sebaceous Glands

Oil-producing exocrine glands present everywhere except the palms and soles that dump sebum into hair follicles to soften hair and reduce water loss.

Arrector Pili Muscle

A smooth muscle ribbon attached to a hair follicle that pulls the follicle upright when contracted, causing goosebumps.

Hair Shaft Layers

The three concentric structures of hair: the central core (medulla), the pigmented main bulk (cortex), and the single overlapping outer cellular layer (cuticle).

Lanugo

A fine, downy hair coat covering a developing fetus between months 5 and 7 of gestation.

Hyponychium

The region directly beneath the free edge of the nail where debris typically collects.

Eponychium

The narrow fold of stratum corneum at the base of the nail plate, commonly referred to as the cuticle.

Lunula

The white, half-moon-shaped region at the base of the nail plate produced by a localized thick stratum basale layer.

Decubitus Ulcer

A pressure sore resulting from localized pressure that cuts off tissue blood flow, leading to cellular necrosis.

Basal Cell Carcinoma

The most common and least aggressive form of skin cancer, originating in the stratum basale and curable in 99% of cases.

Squamous Cell Carcinoma

A rapidly growing skin cancer originating from keratinocytes in the stratum spinosum, commonly appearing on the scalp, ears, lips, and hands.

Melanoma

A highly dangerous and aggressive cancer caused by the uncontrolled proliferation of melanocytes.

Rule of Nines

A standardized clinical method dividing the body surface into 11 sections of approximately 9% each to estimate burn area and fluid loss risks.

Hypertrophic Scar

A raised, dense collagen scar that remains strictly confined within the boundaries of the original injury.

Keloid Scar

An overgrown, paler scar that expands beyond the original borders of a wound into surrounding undamaged tissue.