A&P: Integumentary system

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Phosolipids

a lipid containing a phosphate group in its molecule

periheral

Epidermis

The outermost layer of the skin, made up of stratified squamous epithelial cells, providing a protective barrier against the environment.

Hypodermis

A layer of connective tissue beneath the dermis, primarily composed of fat and areolar tissue, providing insulation and cushioning.

Keratinocytes

Cells in the epidermis that produce keratin, a protein that strengthens and waterproofs the skin.

Melanocytes

Pigment-producing cells located in the epidermis; they produce melanin, which gives skin its color and protects against UV radiation.

Dermis

The thick, middle layer of the skin composed of connective tissue, containing blood vessels, nerves, sweat glands, and hair follicles.

Thick skin

Skin found on the palms of the hands and soles of the feet, characterized by a thicker epidermis and the presence of the stratum lucidum.

Thin skin

Covers most of the body; has a thinner epidermis and lacks the stratum lucidum.

Stratum basale

The deepest layer of the epidermis, where mitosis occurs to produce new skin cells.

Stratum spinosum

A layer of the epidermis that provides strength and flexibility; contains spiny-shaped keratinocytes.

Stratum granulosum

A layer of the epidermis where keratinocytes begin to die and accumulate keratohyalin granules.

Stratum lucidum

A clear, thin layer of dead keratinocytes found only in thick skin.

Papillary layer

The upper layer of the dermis, composed of loose connective tissue; contains dermal papillae that form fingerprints.

Reticular layer

The lower layer of the dermis, made of dense irregular connective tissue, providing strength and elasticity.

Friction ridges

Raised portions of the skin (such as fingerprints) that enhance grip and tactile sensitivity.

Cleavage lines

Natural lines of tension in the skin caused by the arrangement of collagen fibers in the dermis.

Flexure lines

Lines on the skin where it folds during movement, such as on the palms and fingers.

Melanin

A pigment produced by melanocytes that gives skin its color and protects against UV damage.

Carotene

A yellow-orange pigment found in the skin, derived from the diet.

Hemoglobin

A protein in red blood cells that gives blood its red color; contributes to the pinkish hue of the skin.

Hair (pili)

Keratinized structures that grow from hair follicles; provide protection, insulation, and sensory input.

Nail

A hard, keratinized structure at the tips of fingers and toes; protects the digits and aids in manipulation.

Skin appendages

Structures associated with the skin, including hair, nails, and glands.

Hair follicle

The structure in the dermis from which hair grows; includes a bulb, root, and shaft.

Sudoriferous glands

Sweat glands in the skin; include eccrine and apocrine glands.

Eccrine sweat glands (SG)

Glands that secrete sweat directly onto the skin surface; play a key role in thermoregulation.

Apocrine sweat glands (SG)

Glands located in the axillary and genital regions; secrete a thicker sweat into hair follicles, activated during puberty.

Mammary glands

Modified sweat glands that produce milk in females.

Ceruminous glands

Specialized glands in the ear canal that produce earwax (cerumen).

Sebaceous glands

Oil glands in the skin that produce sebum, which lubricates and waterproofs the skin and hair.

Acid mantle

A thin, slightly acidic film on the skin's surface that inhibits the growth of harmful microorganisms.

Skin cancer

Abnormal growth of skin cells, often caused by UV exposure.

Basal cell carcinoma

The most common type of skin cancer; originates in the stratum basale and rarely metastasizes.

Squamous cell carcinoma

A type of skin cancer that arises from the stratum spinosum; can metastasize if untreated.

Melanoma

The most dangerous form of skin cancer; develops in melanocytes and is highly metastatic.

Burns

Injuries to the skin caused by heat, chemicals, electricity, or radiation; classified by severity (first, second, third degree).

ABCD rule

A method for recognizing melanoma: Asymmetry, Border irregularity, Color variation, and Diameter greater than 6mm.

Rule of nines

A method for estimating the total body surface area affected by burns, dividing the body into sections worth 9% each.

Dermatitis

Inflammation of the skin, characterized by redness, swelling, and itching.