Thank you for the great question!

The top layer of skin, which is the largest organ in the human body, is called the epidermis. The top layer of skin is primarily made up of cells called keratinocytes. The main purpose of these cells is to make a physical barrier between the person and the environment, basically to keep water in the body and harmful things out of the body.

Skin cells protect against pathogens like bacteria and viruses, in addition to environmental threats like extreme heat and UV radiation from sunlight. Other interesting facts about skin cells show that their purpose is to help defend the body against the outside world. For example, the epidermis contains no blood vessels, allowing the skin to regulate temperature between the body and the outside world.

One final fact, because the epidermis does not contain blood vessels, cells on the body’s surface absorb the oxygen they need to survive from the surrounding air. Pretty neat!

The purpose of skin cells are to protect you. They serve as a first line defense against things like heat, UV radiation from the sun, bacteria/parasites/viruses. Your skin cells produce a protein called melanin, which gives your skin color. Melanin plays an important part in absorbing UV radiation and preventing it from going deeper into your body. The more melanin you have, the more UV you can absorb. This is why people with very fair skin tend to get a sunburn much more easily than those with darker skin tones. Your skin cells also provide a physical barrier for things that might come into the body and harm you (e.g. bacteria). Skin cells are also known as epithelial cells. This a general name for cells that line your body and your body cavities.

Skin cells form a barrier between the inside of the animal's body and the outside world. The environment inside of the body is necessary to keep the animal alive, so loss of skin will result in death as the outside environment rushes in.

Skin cells have a number of purposes and there are a few different types of skin cells. There’s a thin layer of dead cells in the shallowest layer of skin. These cells have not only died, they’ve formed a tight wall around nearly your entire body. This is really important because you encounter stuff in the environment all the time that could be dangerous if it got into your body. Most importantly, these dead skin cells “waterproof” your body and protect bacteria from getting into you through your skin. Below those cells there are alive cells which have more structural purposes. These cells make the skin strong and elastic which cushions the body from the various stresses it might encounter.

Also, there are many nerve endings in the deeper parts of the skin that can sense touch, pain, and heat. As you may expect, there are cells that grow hair and make sweat in the skin. If you get really deep into the skin, eventually you find blood vessels and deeper structures like bones, muscles, and other tissues. So the main purpose of skin cells are to protect and cushion the body, sense the environment, and respond to the environment (this is what sweating would be).