Chapter 5: The Integumentary System

Vocabulary flashcards covering key terms and concepts from the notes on the integumentary system.

Integumentary system

The body system comprising the skin and its accessory structures (hair, nails, cutaneous glands).

Skin and its Functions (6)

The body's largest organ; functions include resistance to trauma and infection, water retention, vitamin D synthesis, sensation, thermoregulation, and nonverbal communication.

Epidermis

The outer, avascular layer of the skin made of keratinized stratified squamous epithelium; nourished by diffusion from the dermis; superficial cells are dead; sparse nerve endings

Dermis - Contains (6) & Organization

The connective tissue layer beneath the epidermis containing collagen, blood vessels, nerves, glands, hair follicles, and receptors; organized into papillary and reticular layers.

Hypodermis (subcutaneous tissue) - Location, Composition (2), & Function (3)

Not a true skin layer; located beneath the dermis; consists of adipose and areolar tissue; functions in energy storage, insulation, and anchoring the skin to deeper tissues.

Dermal papilla

A projection of the dermis that supplies nutrients to the epidermis and supports hair growth.

Tactile corpuscle (Meissner corpuscle)

Touch receptor located in the dermal papillae that detects light touch.

Lamellated corpuscle (Pacinian corpuscle)

Pressure receptor in the dermis that detects deep pressure and vibration.

Hair follicle

Tubelike invagination of the epidermis that produces hair; extends into the dermis and sometimes hypodermis.

Hair receptor

Nerve fibers that respond to movement of hair.

Piloerector muscle (arrector pili)

Smooth muscle that causes goose bumps when contracted.

Sebaceous gland

Oil glands that secrete sebum into hair follicles to keep skin and hair from drying out.

Merocrine (eccrine) sweat gland

Sweat glands that are widespread; produce watery perspiration to cool the body; ducts open to skin surface via pores.

Apocrine sweat gland

Sweat glands found in specific areas (groin, anal region, axilla, areola, beard); ducts open into hair follicles; odoriferous; active during puberty; associated with pheromones.

Ceruminous gland

Glands in the auditory canal that produce cerumen (earwax) to keep the canal and eardrum protected.

Mammary gland

Modified apocrine gland that develops during pregnancy to produce milk.

Stratum corneum

#1: Outermost epidermal layer of dead, scaly, keratinized cells; provides barrier function.

Stratum lucidum

#2: Clear layer found only in thick skin; cells lack organelles

Stratum granulosum

#3: Layer where keratinocytes accumulate dark granules and begin to die.

Stratum spinosum

#4: Layer with several layers of keratinocytes; contains dendritic (Langerhans) cells.

Stratum basale

#5: Deepest epidermal layer; a single layer of stem cells that proliferate to form keratinocytes; contains melanocytes and Merkel cells.

Keratinocytes

Most abundant epidermal cells; synthesize keratin and form most of the epidermis.

Melanocytes

Cells in the stratum basale that produce melanin, which protects DNA from ultraviolet radiation.

Melanin

Pigment produced by melanocytes; variations in color (brown to black) depend on type and distribution of melanin.

Hemoglobin

Red pigment in blood that contributes to skin color when oxygenated.

Carotene

Yellow-orange pigment that concentrates in the stratum corneum.

Cyanosis

Bluish skin color due to lack of oxygen in the blood.

Erythema

Redness resulting from increased blood flow to the skin.

Pallor

Pale or ashen skin due to reduced blood flow or other factors.

Albinism

Genetic lack of melanin production resulting in white or very pale skin.

Jaundice

Yellowing of the skin due to elevated bilirubin and liver dysfunction.

Hematoma

Bruise; localized collection of blood outside the vessels.

Friction ridges

Ridges on fingertips that enhance grip and create fingerprints.

Flexion lines

Creases near joints where skin attaches to deeper tissue.

Freckles

Flat, melanized patches of skin that vary with heredity and UV exposure.

Mole (nevus)

Elevated patch of melanized skin; a pigmented nevus.

Hemangioma

Discolored birthmark caused by benign tumors of capillaries.

Hair (pili)

Keratinized filament growing from a hair follicle; present on most skin except certain areas.

Lanugo

Fine, downy, unpigmented fetal hair.

Vellus hair

Fine, unpigmented hair; common on women and children; many hairs on the body except for certain areas.

Terminal hair

Coarse, pigmented hair that appears after puberty in axillary, pubic, facial regions and on the trunk/limbs.

Hair follicle zones

Bulb (growth base): contains dermal papilla (nutrition) & hair matrix (growth center), root (within follicle), shaft (above skin; dead tissue).

Hair receptor

Nerve endings that detect movement of hair.

Pili (arrector pili)

Smooth muscle that causes hair to stand (goose bumps).

Nails

Derivatives of stratum corneum; made of dead, keratinized cells and adapted for grasping and manipulating objects.

Nail plate

Visible nail portion; composed of dead keratinized cells. nail body, nail root

Nail root

Part of the nail hidden under the skin at the proximal end.

Nail bed

Skin beneath the nail plate; includes the hyponychium (epidermis of nail bed) and nail matrix.

Lunule

The pale crescent at the base of the nail.

Eponychium (cuticle)

Epidermal tissue at the proximal nail fold.

Hyponychium

Epithelium under the free edge of the nail.

Striae (stretch marks)

Stretching of the dermal collagen resulting in visible lines on the skin.

Aging (senescence) of the integumentary system (5)

Age-related degeneration including

• Hair thins, melanocytes die → gray hair

• Mitosis slows → thinner skin

• Sebaceous glands atrophy → dryness

• Fragile vessels → bruising, rosacea

• Impaired thermoregulation → risk of hypothermia & heat stroke

Skin cancer types (3)

Basal cell carcinoma

squamous cell carcinoma

malignant melanoma

UV exposure

Ultraviolet radiation from sun or tanning beds that increases risk of skin cancer.

Burns (degrees)

First degree: epidermis only (red, pain).

Second degree: epidermis and dermis (blistered). ‘

Third degree: full thickness; epidermis and dermis destroyed; risk of contracture.

Basal cell carcinoma

most common, rarely metastasizes; arises from stratum basale

squamous cell carcinoma

may metastasize; from keratinocytes of the stratum spinosum

malignant melanoma

deadliest; from melanocytes; rapidly metastasizes).

Thick skin: Locations (4) and More

palms, soles, fingers/toes; no hair/sebaceous glands, does sweat

Thin Skin

most of body; has hair, sebaceous & sweat glands

Stem cells

divide to form keratinocytes (stratum basale)

Tactile/Merkle cells

sensory receptors (touch) in stratum basale

Dendritic/Langerhans cells

immune surveillance in stratum spinosum & granulosum

Reticular Layer

deep, dense irregular CT, forms striae (stretch marks)

Papillary Layer

superficial, areolar tissue, blood vessels

Eumelanin

brownish black

Pheomelanin

reddish yellow

Nail fold

nail groove

Cutaneous Glands (4)

• Sudoriferous glands (sweat)

• Sebaceous glands

• Ceruminous glands

• Mammary glands

Sudoriferous glands (sweat) (2)

• Apocrine: in groin, axilla, areola, beard; ducts open into hair follicle; stress/sexual activity; pheromones

• Merocrine (eccrine): most numerous; palms, soles, forehead; watery sweat for cooling

Sebaceous glands

sebum (oily), open into hair follicle

Ceruminous glands

earwax, protective

Mammary glands

modified apocrine, produce milk