Human skin consists of many types of cells organized in three main layers. Click the name of each skin layer in the illustration below to learn about its functions and the cell types it contains.
The correct answer is all of the above … and more! Skin also helps regulate body temperature and protects the body from the environment, including from ultraviolet radiation.
One important function of the epidermis is to produce vitamin D.
Vitamins are organic nutrients that the body needs in very small amounts to help perform chemical reactions. Most vitamins are obtained by eating food, but there are some, like vitamin D, that the body can also make on its own.
We can obtain vitamin D from our diet, but most of the vitamin D in our bodies is produced through a series of chemical reactions. These reactions start in the skin with a molecule with a complicated name, 7-dehydrocholesterol, and sunlight.
Spending a lot of time indoors, away from sunlight, is a risk factor for vitamin D deficiency. Living in the northern latitudes, and not near the equator, is another risk factor. Beef liver and fatty fish like tuna and salmon are rich in vitamin D; eating a lot of these foods reduces the risk of vitamin D deficiency.
The US Endocrine Society defines as less than 20 ng/ml of 25-hydroxy vitamin D circulating in the blood.
Vitamin D deficiency can lead to rickets in children and osteomalacia in adults, as well as fatigue and depression.
is the softening and weakening of bones in children, usually caused by a prolonged deficiency in vitamin D, although it can also have other causes. Like rickets, is a softening of the bones but occurs in adults and can lead to bone fractures.
The risk of vitamin D deficiency increases among people with darker skin colors. Darker skin prevents UV radiation from penetrating the epidermis, reducing the body’s ability to synthesize vitamin D.
