Integumentary System Practice Flashcards

Vocabulary terms covering the structure, layers, cell types, glands, and clinical conditions of the integumentary system based on lecture notes.

Integumentary system

Is composed of skin and its derivatives (hair, nails, glands).

Dermatology

The medical specialty that deals with the diagnosis and treatment of integumentary system disorders.

Skin Dimensions

The largest organ of the body, measuring about $1$ to $4\,mm$ thick, with an area of $2\,m^2$ ($22\,sq\,ft$) and a weight of $4.5-5\,kg$ ($10-11\,lbs$).

Keratinization

The process of accumulation of keratin into keratinocytes.

Serous Membranes

Membranes that line cavities and cover visceral organs, consisting of simple squamous epithelium over loose connective tissue and secreting watery fluid for lubrication.

Mucous membranes

Membranes that line cavities opening to the exterior and contain Goblet cells that secrete mucous.

Cutaneous membrane

The skin, which covers the body and is the major organ of the integumentary system.

Epidermis

The most superficial layer of the skin composed of stratified keratinized squamous epithelium with no blood vessels or nerve endings.

Keratinocytes

Representing $90\%$ of epidermal cells, these manufacture and store the protein keratin, providing hardness and water-resistant properties.

Melanocytes

Representing $8\%$ of epidermal cells, these neural crest-derived cells are located in the stratum basale and produce the dark pigment melanin.

Merkel cells

Oval-shaped mechanoreceptors located in the deepest layer of the epidermis that are essential for light touch sensation.

Langerhans cells

Macrophage-like dendritic cells (antigen-presenting immune cells) prominent in the stratum spinosum.

Stratum basale (germinatuvum)

The deepest epidermal layer consisting of a single layer of cuboidal to columnar basal cells that act as precursors for keratinocytes.

Stratum spinosum

Known as the thorn-like or prickly layer, it consists of $8-10$ layers of keratinocytes and contains Langerhans cells.

Stratum granulosum

A grainy-appearing layer of $2-5$ layers of flat keratinocytes where keratinization begins and Keratohyalin granules are found.

Stratum lucidum

A smooth, translucent layer of $3-5$ layers of clear, dead keratinocytes found only in the thick skin of the palms, soles, and digits.

Stratum corneum

The most superficial 'horny' layer of the epidermis consisting of $15$ to $30$ layers of dry, dead, keratinized cells that protect against microbes and dehydration.

Dermis

A tough and elastic layer formed from connective tissue containing collagen and elastic fibers, blood vessels, lymph vessels, and sensory nerve endings.

Striae

Permanent stretch marks resulting from the rupture of elastic fibers when skin is overstretched.

Papillary Layer

The superficial layer of the dermis made of loose, areolar connective tissue containing Meissner corpuscles and finger-like projections called dermal papillae.

Reticular Layer

The deeper dermis layer comprising $80\%$ of the dermis, composed of dense irregular connective tissue providing skin flexibility.

Hypodermis (subcutaneous)

Layer of adipose and areolar connective tissue that anchors skin to underlying structures, functions as a shock absorber, and stores fat.

Sebaceous glands

Oil glands that secrete sebum into hair follicles to keep hair soft and provide bactericidal and fungicidal protection.

Eccrine (merocrine) sweat glands

Simple coiled tubular exocrine glands found on the forehead, palms, and soles that function to cool the body.

Apocrine sweat glands

Viscous sweat glands located in the axilla and groin that open into hair follicles and start functioning at puberty.

Ceruminous glands

Modified sudoriferous glands in the external ear that secrete cerumen (ear wax).

Albinism

Inherited inability to produce melanin because of the inability to synthesize the enzyme tyrosinase.

Vitiligo

An autoimmune disorder characterized by the partial or complete loss of melanocytes from patches of skin, producing white spots.

Jaundice

The buildup of the yellow pigment bilirubin in the skin.

Cyanosis

A condition where the skin appears blue because the blood is not picking up adequate oxygen.

Arrector Pili

Bundles of smooth muscle fibers that contract in response to fear or cold, causing 'goose flesh' and trapping an insulating layer of air.

Lunula

The white, crescent-shaped area at the base of the nail root.

Eponychium

Commonly known as the cuticle, it occupies the space between the finger skin and the nail plate to provide a waterproof barrier.

Hyponychium

The waterproof barrier area between the free edge of the nail plate and the fingertip skin.

Blood Reservoir

A function of the skin where it holds $8-10\%$ of the total blood in a resting adult.