The busy middle
Under the top layer is the dermis (DER-mis). It's much thicker than the top layer, and it's alive all the way through.
If the top layer is a shield, the dermis is the busy workshop behind it. Blood vessels, nerves, hair roots and tiny glands all live here.
When a scrape bleeds, it has reached the dermis, because that's where the blood vessels are.
Stretch and bounce back
The dermis is full of strong threads made of collagen (KOL-uh-jen). Collagen makes skin tough, so it doesn't tear easily.
It also has springy threads called elastin (ee-LAS-tin). Elastin lets skin stretch and then snap back, like a rubber band.
Gently pinch the skin on the back of your hand and let go. See how fast it goes flat? That's elastin at work. Kids have lots of it.
As people get much older, their bodies make less collagen and elastin. That's one reason grandparents often have soft wrinkles.
Blood vessels and feelers
Tiny blood vessels called capillaries (KAP-uh-lair-eez) bring food and oxygen to your skin cells.
These vessels help control heat too. On a hot day they open wide, so warm blood comes near the surface and gives off heat. That's why your cheeks may look pink or feel warm after running.
When you're cold, they squeeze narrow and keep warm blood deeper inside.
The dermis is also packed with nerve endings. These tiny sensors feel touch, pressure, heat, cold, itch and pain.
Hair roots and glands
Every hair grows from a little pocket in the dermis called a follicle (FOL-ih-kul).
Next to each hair is a tiny oil gland. It makes an oil called sebum (SEE-bum) that keeps your hair and skin soft and a little waterproof.
Sweat glands live here too. They are tiny coiled tubes that send sweat up to little openings on your skin called pores.
Each hair root also has a teeny muscle attached. When those muscles squeeze, you get goosebumps.