Overview The three layers of skin on top of muscle tissue.What is the skin?

The skin is the bodys 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-MEINT-a-ree) system. Integumentary means a bodys 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 skins thickness. This middle layer of skin:

The bottom layer of skin, or hypodermis, is the fatty layer. The hypodermis:

One inch of your skin has approximately 19 million skin cells and 60,000 melanocytes (cells that make melanin or skin pigment). It also contains 1,000 nerve endings and 20 blood vessels.

As the bodys external protection system, your skin is at risk for various problems. These include:

You lose collagen and elastin as you age. This causes the skins middle layer (dermis) to get thinner. As a result, the skin may sag and develop wrinkles.

While you cant stop the aging process, these actions can help maintain healthier skin:

You should call your healthcare provider if you experience:

A note from Cleveland Clinic

As the bodys largest organ, your skin plays a vital role in protecting your body from germs and the elements. It keeps your body at a comfortable temperature, and nerves beneath the skin provide the sense of touch. This external body covering can have serious problems like skin cancer, as well as more common issues like acne and skin rashes. Your healthcare provider can offer tips to help keep skin healthy.

Read more here:
Skin: Layers, Structure and Function - Cleveland Clinic