Layers of the Skin
This outermost layer of the skin is composed entirely of stratified squamous epithelial cells and lacks its own blood supply.
epidermis
These specialized cells located at the base of the epidermis produce the pigment responsible for skin and hair color.
melanocytes
hese glands secrete an oily mixture into hair follicles to keep the skin pliable and prevent hair from becoming brittle.
sebaceous glands
The skin acts as the body's first line of defense against infection, which means it plays a major role in this body system.
immune system
This mild type of burn, like a typical sunburn, damages only the epidermis, causing redness and mild pain.
first-degree burn
This thick, inner layer of skin houses the majority of the skin's accessory structures, including nerves, blood vessels, and glands.
dermis
This tough, waterproof protein is produced by epidermal cells as they move upward, eventually filling the cells and making the skin a strong barrier.
keratin
These specific sweat glands are found all over the body and are primarily responsible for evaporative cooling.
eccrine or merocrine sweat glands
To release heat when you are too warm, blood vessels in the dermis undergo this process, where they widen to allow more blood flow near the surface.
vasodilation
Characterized by the formation of blisters, this level of burn damages both the epidermis and the upper region of the dermis.
second-degree burn
While not technically part of the skin, this underlying layer is composed of adipose (fat) tissue that insulates the body.
subcutaneous layer
Exposure to this type of environmental radiation triggers melanocytes to produce more pigment, resulting in a suntan.
ultraviolet (UV) radiation
Activating during puberty, these sweat glands are found mainly in the armpits and groin and secrete a thicker fluid that bacteria feed on, causing body odor.
sweat glands
The skin plays a key role in synthesizing this vitamin, which requires sunlight to activate and helps the digestive system absorb calcium.
Vitamin D
These tiny, smooth muscles contract in response to cold temperatures, pulling hair upright and creating "goosebumps."
arrector pili muscles
Cells in the epidermis die as they pushed upward because they are cut off from the blood supply found in this specific lower layer.
dermis
These are the actual cells that make up 90% of the epidermis, named for the specific water-resistant protein they produce.
keratinocytes
This is the biological term for the mixture of fats, cholesterol, and proteins secreted by oil glands.
sebum
When you are cold, blood vessels in the dermis do this, narrowing to keep warm blood closer to your internal organs.
vasoconstriction
This is the most common type of skin cancer, usually appearing as a shiny bump on sun-exposed areas like the face.
basal cell carcinoma
This topmost, dead layer of the epidermis consists of flattened, scale-like cells that constantly flake off and form the dust in our homes.
stratum corneum
Albinism is a genetic condition where a person's cells are completely unable to produce this specific pigment.
melanin
Acne occurs when these tiny structures, from which hair emerges, become blocked by excess sebum and dead skin cells.
hair follicles
This term refers to the steady-state, balanced internal environment that the integumentary system helps maintain for the body.
homeostasis
This is the name of the actively growing, crescent-shaped white area at the base of the fingernail.
lunula