Chapter 5: The Integumentary System Vocabulary

Vocabulary practice flashcards covering anatomical terminology, structures, layers, cell types, glands, and disorders of the integumentary system from Chapter 5.

Epidermis

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

Dermis

The deeper layer of the skin located beneath the epidermis, composed of connective tissue containing collagen and elastic fibers.

Hypodermis

Also called the subcutaneous layer; a layer deep to the dermis (not a layer of the skin) composed of areolar and adipose tissue.

Keratinocytes

Epidermal cells that produce keratin, a tough fibrous protein that provides protection against heat, microbes, and chemicals.

Melanocytes

Epidermal cells that produce the pigment melanin, which absorbs damaging ultraviolet light.

Intraepidermal Macrophages

Also known as Langerhans cells; epidermal cells that participate in immune responses by recognizing and processing foreign antigens.

Tactile Epithelial Cells

Also known as Merkel cells; epidermal cells in the deepest layer that function in the sensation of touch alongside a tactile disc.

Stratum Basale

The deepest layer of the epidermis, consisting of a single row of cuboidal or columnar keratinocytes that continuously undergo cell division.

Stratum Spinosum

An epidermal layer superficial to the stratum basale, composed of multiple layers of flattened keratinocytes that begin keratinizing.

Stratum Granulosum

An epidermal layer where keratinocytes flatten out, accumulate lamellar granules releasing water-repellent lipids, and undergo apoptosis.

Stratum Lucidum

A clear layer present ONLY in the thick skin of the palms, fingertips, and soles, containing additional keratin for protection from abrasion.

Stratum Corneum

The most superficial layer of the epidermis, consisting of flattened, dead keratinocytes that form a protective outer barrier.

Callus

An abnormal thickening of the stratum corneum caused by constant exposure of skin to friction.

Eumelanin

A form of melanin pigment that imparts a brown-to-black color to hair and skin.

Pheomelanin

A form of melanin pigment that imparts a yellow-to-reddish color to hair and skin.

Carotene

A yellow-orange pigment stored in the stratum corneum and adipose tissue that acts as a precursor for vitamin A.

Hemoglobin

An oxygen-carrying red pigment in red blood cells that contributes a reddish tint to the skin depending on dermal blood flow.

Cyanotic

A diagnostic condition characterized by bluish skin coloration due to a severe lack of oxygen.

Jaundice

A diagnostic condition marked by yellowing of the skin and eyes due to a buildup of bilirubin, indicating liver malfunction.

Erythema

Redness of the skin resulting from capillary dilation due to injury, inflammation, heat exposure, or allergic reactions.

Pallor

An abnormal paleness of the skin that typically occurs during conditions such as shock or anemia.

Albinism

A congenital disorder characterized by a complete or partial absence of melanin pigment in the skin, hair, and eyes due to an enzyme defect.

Vitiligo

A chronic autoimmune condition that results in patches of depigmentation across the skin.

Papillary Region

The superficial portion of the dermis (about one-fifth) consisting of areolar connective tissue, dermal papillae, capillary loops, and corpuscles of touch.

Reticular Region

The deeper portion of the dermis (about four-fifths) consisting of dense irregular connective tissue with thick collagen fibers, hair follicles, and glands.

Corpuscle of Touch

Also called a Meissner corpuscle; an encapsulated mechanoreceptor in dermal papillae that senses the onset of touch and low-frequency vibrations.

Lamellated Corpuscle

Also called a Pacinian corpuscle; an encapsulated sensory receptor located deep in the dermis or hypodermis that senses high-frequency vibrations.

Sebaceous Glands

Exocrine oil glands connected to hair follicles that secrete an oily substance called sebum.

Sebum

An oily secretion containing triglycerides, cholesterol, proteins, and inorganic salts that keeps skin soft and inhibits bacterial growth.

Eccrine Sweat Glands

The most abundant sweat glands in the body that secrete a watery sweat containing $\text{Na}^+$ and $\text{Cl}^-$ for thermoregulation.

Apocrine Sweat Glands

Sweat glands in hairy areas (axillae, groin, bearded face) that secrete a viscous, lipid- and protein-rich fluid active during emotional stress and sex.

Ceruminous Glands

Modified apocrine sweat glands in the external auditory canal that produce cerumen (earwax).

Lanugo

Fine, nonpigmented, downy hair that covers the fetus during development.

Terminal Hair

Long, coarse, heavily pigmented hair found on eyebrows, eyelashes, scalp, and pubic regions.

Vellus Hair

Short, fine, pale hairs commonly known as peach fuzz that cover most of the body during childhood.

Eponychium

Also called the cuticle; a narrow band of stratum corneum of the epidermis extending around the proximal border of the nail body.

Hyponychium

A region of thickened stratum corneum beneath the free edge of the nail plate that secures the nail to the fingertip.

Contact Inhibition

The physiological mechanism in epidermal wound healing where migrating basal cells cease movement upon coming into contact with one another.

Pressure Ulcer

Also known as a bed sore; localized skin and tissue necrosis caused by prolonged deficiency of blood flow when subject to pressure.

Rule of Nines

A clinical system used to estimate the percentage of total body surface area affected by burns in adults by dividing the body into multiples of 9%.