Chapter 06 - The Integumentary System Vocabulary

A comprehensive set of vocabulary flashcards covering key terms, cell types, skin layers, glands, hair/nail anatomy, pathology, and burn classifications from Chapter 06 of Saladin Anatomy & Physiology.

Dermatology

The scientific study and medical treatment of the integumentary system.

Integumentary System

The organ system consisting of the skin, hair, nails, and associated glands.

Epidermis

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

Dermis

The deeper connective tissue layer of the skin beneath the epidermis, composed mainly of collagen and ranging from $0.2\,\text{mm}$ to $4\,\text{mm}$ thick.

Hypodermis

The layer of connective tissue beneath the dermis (subcutaneous tissue) containing areolar and adipose tissue, which binds skin to underlying tissues.

Thick Skin

Skin covering the palms, soles, and corresponding surfaces of fingers and toes; features sweat glands and a stratum lucidum, but lacks hair follicles and sebaceous glands.

Thin Skin

Skin covering most of the body with an epidermis about $0.1\,\text{mm}$ thick; features hair follicles, sebaceous glands, and sweat glands, but lacks a stratum lucidum.

Keratinocytes

The great majority of epidermal cells, responsible for synthesizing keratin.

Stem Cells

Undifferentiated cells located in the stratum basale that divide and give rise to keratinocytes.

Melanocytes

Epidermal cells in the stratum basale that synthesize melanin pigment to shield keratinocyte DNA from ultraviolet radiation.

Tactile Cells

Receptor cells in the epidermis specialized for touch sensation.

Dendritic Cells

Macrophages found in the stratum spinosum and stratum granulosum that guard against pathogens and help activate the immune system.

Stratum Basale

The deepest layer of the epidermis consisting of a single row of stem cells, melanocytes, and tactile cells firmly attached to the dermis.

Stratum Spinosum

An epidermal layer several cell layers thick where keratinocytes are joined by desosomes and contain web-like systems of keratin filaments.

Stratum Granulosum

A layer of $3$ to $5$ rows of flattened keratinocytes containing keratohyaline and lamellated granules that slow water loss.

Stratum Lucidum

A thin, clear layer of flat, dead keratinocytes found only in thick skin, superficial to the stratum granulosum.

Stratum Corneum

The most superficial layer of the epidermis, comprising up to three-quarters of its thickness and composed of dead, flat, keratinized cells.

Dermal Papillae

Finger-like upward extensions of the dermis that interlock with epidermal ridges to form the boundary between dermis and epidermis.

Friction Ridges

Markings on fingertips formed by dermal papillae pushing up overlying epidermis, which enhance grip, amplify touch, and create unique fingerprints.

Subcutaneous Fat

Adipose tissue predominant within the hypodermis that provides thermal insulation, padding, and energy storage.

Eumelanin

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

Pheomelanin

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

Cyanosis

Blueness of the skin resulting from a deficiency of oxygen in the circulating blood.

Erythema

Abnormal redness of the skin caused by increased blood flow.

Pallor

Pale or ashen color of the skin that occurs when blood flow through the skin is diminished.

Albinism

A genetic lack of melanin synthesis that results in milky white hair and skin, and blue-gray or pink eyes.

Jaundice

Yellowing of the skin and sclera due to high levels of bilirubin in the blood, often associated with compromised liver function.

Hematoma

A mass of clotted blood showing through the skin, commonly known as a bruise.

Arrector Pili Muscle

A bundle of smooth muscle cells associated with a hair follicle that contracts to pull the hair upright in response to cold or fear.

Lanugo

Fine, downy, unpigmented hair that appears on the fetus in the last $3$ months of development.

Vellus

Fine, pale hair that replaces lanugo by the time of birth, constituting most of the body hair on children and women.

Terminal Hair

Longer, coarser, and heavily pigmented hair found on eyebrows, eyelashes, scalp, and after puberty, in axillary, pubic, and male facial areas.

Alopecia

Patterned thinning of hair or baldness occurring as hair loss outpaces replacement, commonly occurring after age $40$.

Nail Plate

The hard part of the nail, comprising the free edge, visible nail body, and underlying nail root.

Nail Matrix

The growth zone of thickened stratum basale located at the proximal end of the nail bed, growing at about $1\,\text{mm}$ per week in fingernails.

Lunule

The opaque white crescent at the proximal end of a nail caused by the thickness of the underlying nail matrix.

Eponychium

A narrow zone of dead skin overhanging the proximal end of the nail, also called the cuticle.

Apocrine Sweat Glands

Sweat glands in the groin, axilla, areola, and beard area that secrete milky, fatty-acid-rich sweat into hair follicles in response to stress and sexual stimulation.

Merocrine Sweat Glands

Abundant simple tubular sweat glands that secrete watery perspiration directly onto the skin surface to cool the body.

Bromhidrosis

Disagreeable body odor produced by bacterial action on fatty acids in apocrine sweat.

Myoepithelial Cells

Specialized contractile cells in sweat glands that squeeze perspiration up the duct in response to sympathetic stimulation.

Sebaceous Glands

Glands associated with hair follicles that secrete an oily, bactericidal substance called sebum to keep hair and skin soft.

Ceruminous Glands

Modified apocrine glands located in the external ear canal that produce cerumen (earwax).

Basal Cell Carcinoma

The most common and least deadly form of skin cancer, arising from the stratum basale as a small, shiny bump with a central depression.

Squamous Cell Carcinoma

Skin cancer originating from keratinocytes in the stratum spinosum, forming raised, reddened, scaly lesions that can metastasize to lymph nodes.

Malignant Melanoma

The most aggressive and deadly skin cancer, originating from melanocytes, often showing asymmetrical borders, varied colors, and diameter over $6\,\text{mm}$.

ABCD Rule

Diagnostic guide for recognizing melanoma based on Asymmetry, Border irregularity, Color variation, and Diameter greater than $6\,\text{mm}$.

Eschar

Burned, dead tissue produced by severe skin burns that must be removed via debridement.

First-Degree Burn

A partial-thickness burn involving only the epidermis, causing redness, slight edema, and pain.

Second-Degree Burn

A partial-thickness burn involving the epidermis and part of the dermis, characterized by red, tan, or white blistered and painful lesions.

Third-Degree Burn

A full-thickness burn involving the epidermis, all of the dermis, and often deeper tissues, requiring fluid replacement and skin grafts.

Autograft

A skin graft taken from another location on the same individual's body.

Allograft

A skin graft taken from an unrelated person, usually a deceased donor.

Six principal functions of the skin

Protection, barrier functions, vitamin D synthesis, sensation, thermoregulation, and nonverbal communication.

Layers of the epidermis in order from deep to superficial

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

Epidermal vascularity

The epidermis is avascular; nutrients reach its cells by diffusion from dermal blood vessels.

Keratinocyte life cycle

Keratinocytes arise in the stratum basale, are pushed upward toward the surface, synthesize keratin and die, and eventually flake off over $30$ to $40$ days.

Primary fibrous components of the dermis

Mainly collagen, accompanied by elastic and reticular fibers.

Three primary pigments determining skin color

Melanin, hemoglobin, and carotene.

Three main parts of a hair

The bulb, root, and shaft.

Hair Matrix

The active growth center of the hair located within the hair bulb.