Even if it does not have the "boxy" organ appearance of heart, liver, kidneys, skin is also an organ of our body. Like the heart, liver and kidneys, skin consists of cells and tissues that perform a specific function in our body.

The cells and tissues of our skin perform the main role of protecting our body against the exterior harmful agents and factors. Besides this, it has several other roles such as offering a base for the hair follicles that allow hair growth (hair also provides protection against outer agents) and permitting the body release the toxins through perspiration. The skin also helps regulating the body's temperature and the amount of water in the body, controls the infections etc.

The skin consists in two main layers: the epidermis and the dermis. The epidermis is the layer found on the outer side of the skin that acts as a barrier against possibly exterior harmful agents. The dermis is placed on the inner side of the skin and it contains all the "ingredients" of this organ: nerves, hair follicles, sweat glands etc.

The epidermis' main function, besides keeping the infections away and preventing our body from losing large amounts of water, is to protect us from the environment, particularly from the sun. Sun rays can be very harmful to our body by producing ultraviolet radiation. Even if the UV radiation cannot be perceived, it has a very harmful action upon our body.

Part of the sun rays are absorbed by the stratum corneum on the epidermis surface, part by the melanin in the epidermal cells and part is dispersed all throughout the skin. The stratum corneum is the dead cells layer - the visible layer of the skin. The melanin is produced by the melanocyte cells placed at the bottom of the epidermis. The melanin is the skin pigment and is responsible for the color of our epidermis. When taking sunbaths this is what gives the tan of the skin - the melanin that changes its color.

The melanocyte cells are responsible also for the melanoma that causes cancer in people that take frequent and prolonged sunbaths. The cancerous mutations within the skin come from the uncontrollably growing number of melanocyte.

The other part of the UV radiation that is scattered all throughout the skin can also be harmful for us, as it creates many high-energy compounds called free radicals. Free radicals have negative effects upon our skin and health as they are very reactive, which means that they can react with and affect the processes of most molecules in their vicinity. Besides the harmful effects they have on skin, like causing it to wrinkle and age prematurely, the free radicals have been found by many scientific studies to play a lead role in severe diseases such as: cardiovascular disease, various types of cancer, Alzheimer's disease, Parkinson's disease etc.

This is why it is highly important for us to eat vegetables and fruits that contain all types of antioxidants and vitamins that annihilate the destroying effect an elevated number of free radicals can have upon our immune system. Normally, the defense shield of our body against free radicals can neutralize their effects, but overexposure to UV radiation can lead to a high number of free radicals within our bodies, that exceed the possibilities of our immune system to fight against them.