Integumentary System

Cutaneous membrane

Skin; protects the body from the outside environment

Mucous membrane

Lines body passages; produces mucus and protects/lubricates surfaces

Serous membrane

Lines body cavities and covers organs; reduces friction

Synovial membrane

Lines joints; produces fluid that reduces friction

Epidermis

Outer layer of skin; provides protection

Dermis

Layer under the epidermis containing blood vessels, nerves, hair follicles, and glands

Hypodermis

Layer beneath the dermis; contains fat and connective tissue for insulation and cushioning

Stratum basale

Deepest layer of the epidermis

Stratum spinosum

Second layer of the epidermis

Stratum granulosum

Third layer of the epidermis

Stratum lucidum

Clear layer found in thick skin

Stratum corneum

Outermost layer of the epidermis made mostly of dead cells

Melanin

Pigment that gives skin its color and helps protect against UV radiation

High UV exposure

Associated with more melanin because it provides greater protection from UV damage

Low UV exposure

Associated with less melanin, allowing more UV to help produce vitamin D

Vitamin D

Helps the body absorb calcium and supports strong bones

Folate (Vitamin B9)

Important for DNA production and cell division

Skin cancer

Abnormal growth of skin cells often associated with UV radiation

A — Asymmetry

One half of a mole does not match the other

B — Border

Mole has an irregular or uneven border

C — Color

Mole has multiple or uneven colors

D — Diameter

Mole is larger than about 6 mm

E — Evolving

Mole changes in size, shape, color, or appearance

ABCDE rule

Warning signs used to evaluate changes in moles

Sebaceous gland

Produces sebum (oil) that helps lubricate the skin and hair

Sweat gland

Produces sweat to help cool the body

Hair follicle

Structure in the skin where hair grows

Sensory receptors

Detect sensations such as touch, pressure, pain, and temperature