The skin is the body's largest organ, made of water, protein, fats and minerals. Your skin protects your body from germs and regulates body temperature. Nerves in the skin help you feel sensations like hot and cold.
Your skin, along with your hair, nails, oil glands and sweat glands, is part of the integumentary (in-TEG-you-ME+NT-a-ree) system. "Integumentary" means a body's outer covering.
Three layers of tissue make up the skin:
Your epidermis is the top layer of the skin that you can see and touch. Keratin, a protein inside skin cells, makes up the skin cells and, along with other proteins, sticks together to form this layer. The epidermis:
The dermis makes up 90% of skin's thickness. This middle layer of skin:
The bottom layer of skin, or hypodermis, is the fatty layer. The hypodermis:
As the body's external protection system, your skin is at risk for various problems. These include: