Integumentary System - Vocabulary Flashcards

Glossary-style flashcards covering the major terms and concepts related to the integumentary system from the notes.

Integumentary system

Organ system consisting of the skin, hair, nails, and glands; protects the body, regulates temperature, provides sensation, and aids vitamin D synthesis.

Epidermis

The outer, superficial layer of skin; keratinized stratified squamous epithelium that lacks blood vessels.

Dermis

The inner skin layer beneath the epidermis; contains connective tissue, blood vessels, nerves, glands, and hair follicles.

Stratum basale

Deepest epidermal layer where basal cells proliferate and are anchored to the basement membrane.

Stratum spinosum

Second epidermal layer where keratinocytes begin to develop desmosomes and gain strength.

Stratum granulosum

Third epidermal layer where keratinocytes begin to keratinize and form keratohyalin granules.

Stratum lucidum

Transparent layer found only in thick skin (palms and soles).

Stratum corneum

Most superficial epidermal layer composed of dead, keratin-filled cells; provides waterproofing and protection.

Keratinocytes

Most abundant epidermal cells that produce keratin and form the protective barrier.

Keratinization

Process by which keratinocytes accumulate keratin, die, and form a tough, waterproof layer.

Basement membrane

Nonliving layer that anchors the epidermis to the dermis.

Dermal papillae

projections of the dermis into the epidermis; strengthen the connection and form fingerprints.

Papillary layer

Upper dermal layer (areolar tissue) containing dermal papillae, blood vessels, and nerve endings.

Reticular layer

Deep dermal layer (dense connective tissue) rich in collagen and elastin fibers.

Subcutaneous layer (hypodermis)

Layer beneath the dermis composed of areolar and adipose tissue; binds skin to underlying tissues and provides padding/insulation.

Melanocytes

Skin cells in the epidermis that produce the pigment melanin.

Melanin

Pigment that absorbs UV radiation and determines most skin and hair color.

Dendritic cells (Langerhans cells)

Epidermal immune cells that detect and phagocytose pathogens; participate in immune response.

Merkel cells

Tactile (sensory) cells in the epidermis that communicate with sensory neurons for touch.

Hair matrix

Growth zone at the base of the hair follicle where hair cells divide.

Hair follicle

Tubelike structure that produces hair; associated with sebaceous glands.

Arrector pili muscle

Small smooth muscle that raises hair (goosebumps) when contracted.

Nail matrix

Growth region of the nail responsible for nail production; visible lunula marks the matrix.

Sebaceous glands

Oil-secreting glands that produce sebum; associated with hair follicles; keep skin and hair moisturized.

Sweat glands (sudoriferous glands)

Glands that secrete sweat onto the skin surface or hair follicles for cooling and excretion.

Eccrine (merocrine) sweat glands

Most common sweat glands; produce watery sweat; open directly onto skin surface; active during temperature rise.

Apocrine sweat glands

Sweat glands that secrete thicker fluid into hair follicles; active at puberty and linked to body odor.

Thermoregulation

Maintenance of constant body temperature through sweating, vasodilation, and vasoconstriction.

Vitamin D production

UVB exposure in the skin initiates vitamin D synthesis; liver and kidneys convert precursors to the active form.

25(OH)D (calcidiol)

Circulating form produced by the liver; substrate for conversion to active calcitriol.

Calcitriol

Active vitamin D; increases calcium absorption and supports calcium homeostasis.

UVB radiation

Ultraviolet-B light from the sun that triggers vitamin D production and can cause DNA damage leading to skin cancer.

Skin color factors

Melanin, carotene, and hemoglobin determine color; melanin provides UV protection; blood oxygenation affects appearance.

Erythema

Redness due to increased blood flow in dilated cutaneous vessels.

Pallor

Pale appearance caused by reduced blood flow or anemia.

Cyanosis

Bluish skin color from low oxygen levels, most visible where skin is thin or vessels are dense.

Jaundice

Yellowing of the skin from bilirubin buildup; bilirubin is a product of hemoglobin breakdown and is excreted by the liver.

Wound healing

Process of repairing skin after injury, typically involving inflammatory, proliferative, and remodeling phases.

Inflammatory phase

First phase; vasodilation and increased permeability; immune cells clean debris and pathogens.

Proliferative phase

Second phase; granulation tissue forms, collagen is deposited, blood vessels grow (angiogenesis), epithelization occurs, wound contracts.

Remodeling phase

Final phase; collagen reorganizes, capillary beds diminish, scar may form and become avascular.

Hemostasis

Immediate wound response: vasoconstriction and blood clot formation to stop bleeding.

Granulation tissue

New connective tissue and capillaries that fill a wound during healing.

Angiogenesis

Growth of new blood vessels into the repairing tissue.

Epithelization

Regrowth of the protective epidermal barrier over a wound.

Basal cell carcinoma

Most common and least malignant skin cancer; arises from basal cells of the epidermis.

Squamous cell carcinoma

Skin cancer from keratinocytes of the stratum spinosum; more aggressive than BCC but often curable with early removal.

Melanoma

Most dangerous skin cancer arising from melanocytes; highly metastatic and often lethal.