Integumentary System (Skin) Applied Anatomy

Vocabulary practice flashcards covering the anatomy, cellular layers, functions, and appendages of the human integumentary system.

Skin

The largest organ of the body that covers the external surface, weighing on average $3\text{ to }4\,\text{kg}$ (about $15\%$ of body weight) with a thickness of $0.5\text{ to }4\,\text{mm}$.

Epidermis

The avascular outermost layer of the skin, composed of stratified squamous keratinized epithelium and containing keratinocytes, melanocytes, Langerhans cells, and Merkel cells.

Keratinocytes

The primary and main cell type found in the epidermis.

Stratum Corneum

The most superficial layer of the epidermis, composed of dead, flattened, keratinized cells.

Stratum Lucidum

A clear layer of the epidermis found only in thick skin.

Stratum Granulosum

A middle layer of the epidermis characterized by cells containing keratohyalin granules.

Stratum Spinosum

An epidermal layer characterized by the spiny appearance of its cells.

Stratum Basale (Stratum Germinativum)

The deepest layer of the epidermis, consisting of a single layer of mitotically active cuboidal or columnar cells.

Dermis

The thick and vascular middle layer of the skin made up of connective tissue, containing blood vessels, lymphatics, and nerves.

Papillary Layer

The outer layer of the dermis composed of areolar connective tissue that forms dermal papillae and houses capillary loops and Meissner's corpuscles.

Reticular Layer

The inner layer of the dermis composed of dense irregular connective tissue containing collagen fibres, elastic fibres, sweat glands, hair follicles, sebaceous glands, nerves, blood vessels, and Pacinian corpuscles.

Hypodermis (Subcutaneous Tissue)

The innermost layer of the skin, made up of loose connective tissue and adipose tissue, which anchors skin to underlying structures and provides insulation, shock absorption, and energy storage.

Eccrine Sweat Glands

Sweat glands distributed all over the body (especially palms, soles, and forehead) that secrete watery (hypotonic) sweat for thermoregulation and cooling.

Apocrine Sweat Glands

Sweat glands located in the axilla, areola, and genital area that produce thicker sweat containing proteins and lipids, becoming active at puberty and associated with odour.

Mammary Glands

Skin appendages present in females that are considered modified sweat glands.

Vellus Hair

Soft, thin hair covering most of the body.

Terminal Hair

Thick, long hair located on the scalp, eyebrows, eyelashes, axilla, and pubic area.