Most discussions of skin care center on the face since it’s what we present to the world. It’s almost always exposed, and it has more delicate skin with smaller skin cells than the rest of your body.
But the story of your skin, which equates to about 15% of your total body weight, and what it does for you plays out across your entire skin surface, which equates to about 20 square feet.
It determines how hot you are — literally.
Your skin modulates your body temperature through perspiration, which is the release of water and salts from the sweat glands everywhere on your body, but they’re concentrated on your forehead, armpits, palms of your hand and the soles of your feet.
Your skin also controls your temperature by constricting or enlarging blood vessels at the skin’s surface to retain heat in cold weather and release it in warm weather.
It has its own immune system.
Since your skin faces so many threats as the outermost layer of your body, it has an intricate web of immune cells to defend against infections, irritants, toxins, UV rays and other carcinogens and much more. It contains up to 20 billion T cells that fall into 10 categories, each with a specialized function such as defending against parasites (eosinophils) or to create inflammation in response to allergic reactions and asthma.
It’s very touchy-feely.
It’s so automatic we almost forget about it, but our skin is the seat of our sense of touch, with 1,000 nerve endings in every square inch and hundreds of pain, heat, cold and pressure receptors. Even our hair is wired into our sense of touch, with every strand connected to a nerve ending and potentially capable of sensing something before it’s touched your skin.
It’s actually very bloody.
Our skin is also a reservoir for our blood supply, with about 8% of our total amount residing in 20 feet of blood vessels per square inch. These blood vessels bring nutrients to skin cells, make that regulation of body temperature possible and carry away your skin’s waste products.