Chapter 6: The Integumentary System

Vocabulary flashcards covering key terms from Chapter 6: The Integumentary System.

Integumentary system

The skin and its accessory structures (hair, nails, glands) that protect the body, provide sensory input, regulate temperature, and synthesize vitamin D.

Epidermis

Outermost skin layer; avascular; composed of keratinized stratified squamous epithelium.

Dermis

Middle, supportive connective tissue layer that contains blood vessels, nerves, glands, hair follicles, and other structures.

Hypodermis (subcutaneous layer)

Layer deep to the dermis mainly composed of adipose tissue; provides insulation, cushioning, and energy storage.

Keratinocytes

Primary epidermal cells that produce keratin and form the protective layers of the skin.

Keratin

Fibrous protein that toughens skin, hair, and nails and provides water resistance.

Melanin

Pigment produced by melanocytes that protects skin from UV radiation and determines skin color.

Melanocytes

Cells in the epidermis that synthesize melanin; activity affects skin tone.

Stratum basale

Deepest epidermal layer; a single layer of cells that actively divide; contains Merkel cells and melanocytes.

Merkel cells

Sensory receptors in the stratum basale involved in discriminatory touch.

Stratum spinosum

Layer above basale with several cell layers; keratinocytes with spiny appearance; contains Langerhans cells.

Langerhans cells

Dendritic immune cells in the stratum spinosum that help protect against pathogens.

Stratum granulosum

Layer where keratinocytes flatten and accumulate keratin; melanin can be present in melanosomes; cells begin to die toward the surface.

Stratum lucidum

Clear layer found only in thick skin; contains eleidin and helps form a water barrier.

Stratum corneum

Most superficial epidermal layer; 15–30 layers of dead keratinocytes shed and replaced from deeper layers.

Dermal papillae

Fingerlike projections of the dermis into the epidermis; anchor epidermis to dermis and create fingerprints.

Papillary layer

Superficial dermal layer composed of loose areolar connective tissue; contains dermal papillae.

Reticular layer

Deeper dermal layer made of dense irregular connective tissue; houses hair follicles, glands, and nerves.

Pacinian corpuscles

Lamellated mechanoreceptors in the reticular layer that detect deep pressure and vibration.

Meissner’s corpuscles

Tactile receptors in the dermal papillae that detect light touch.

Nociceptors

Pain receptors in the skin and other tissues.

Thermoreceptors

Receptors that detect changes in temperature (warmth and cold).

Hair

Filament of dead keratinized cells that protects and provides sensation; associated with sebaceous glands and arrector pili muscles.

Sebaceous glands

Oil glands that secrete sebum to lubricate and waterproof skin; activity increases at puberty.

Arrector pili muscles

Smooth muscles that contract to make hair stand up (goosebumps).

Eccrine sweat glands

Sweat glands found all over the body; secrete watery sweat for thermoregulation.

Apocrine sweat glands

Sweat glands in the groin and axilla; secrete a viscous sweat associated with hair follicles and puberty.

Sebum

Oily secretion from sebaceous glands that lubricates and waterproofs the skin.

Nails

Keratinized plates on fingers and toes; nail bed is living; nail body is visible; nail root is hidden under skin; cuticle covers base.

Nail bed

Living tissue beneath the nail plate.

Nail body

Visible hard portion of the nail.

Nail root

Proximal part of the nail located under the skin.

Lunula

Crescent-shaped region at the base of the nail bed.

Hair papilla

Vascularized structure at the base of the hair follicle supplying blood to the hair matrix.

Hair matrix

Growing region of the hair within the hair bulb that produces the hair shaft.

Hair shaft

Visible portion of hair that extends above the skin surface.

Hair cuticle

Outer protective layer of the hair shaft surrounding the cortex.

Cortex

Middle layer of the hair shaft surrounding the medulla; contains most of the pigment.

Medulla

Central core of the hair shaft; often contains pigment in some hair types.

Thick skin

Skin on the palms and soles; five epidermal layers including stratum lucidum; more sensory receptors.

Thin skin

Most skin of the body; four epidermal layers; lacks stratum lucidum.

Dermal papillae role in fingerprints

Projections that increase friction and grip, creating fingerprints.

Vitamin D synthesis

UV light converts skin precursors to active vitamin D, aiding calcium absorption for bone health.

Thermoregulation

Body temperature control via mechanisms like sweating and vascular adjustments.

Wound healing

Multi-step process: blood clotting, fibroblasts form granulation tissue, epidermis regenerates; scars may form.

Burns

Damage from heat, radiation, electricity, or chemicals; classified by depth: first (epidermis), second (epidermis+dermis), third (epidermis+dermis+hypodermis).

Rule of nines

Method to estimate burn area: head/neck 9%, each arm 9%, trunk 36%, genitalia 1%, each leg 18%.

Basal cell carcinoma

Most common skin cancer; arises from stratum basale.

Squamous cell carcinoma

Skin cancer arising from keratinocytes of the stratum spinosum; less common but more aggressive.

Melanoma

Skin cancer originating from melanocytes; highly metastatic; often begins as a mole.

Rickets

Calcium deficiency in children due to insufficient vitamin D, leading to weak bones.

Keratinocytes migration

Cells produced in the deepest epidermal layer migrate toward the surface to replenish outer layers.

Avascular

Lacking blood vessels; a characteristic of the epidermis.

Melanosomes

Vesicles within melanocytes that store and transfer melanin to keratinocytes.