Your skin is a truly wonderful and complex organ, the mechanics of which we are still discovering. What we do know is that the skin is made up of three layers, all of which combine to play an important role in protecting the body.
The outermost layer is the epidermis. This is mainly composed of cells called keratinocytes. They are made from a tough protein called keratin which is also found in hair and nails.
Keratinocytes form several layers and are constantly growing outwards. The exterior cells eventually die and flake off. It takes around five weeks for the newly created cells in the deeper layers to find their way to the surface. This is why when your skin is in poor condition, it takes time to see the results of dietary changes and, in many cases, treatments and skin therapies too.
The thickness of the layer of dead cells on the outer skin varies. This stratum corneum, also known as the horny layer is thicker on some parts of the body – on the soles of the feet, for example, this horny layer is ten times thicker than the skin around your eyes. This layer plays an important role in that it harbours defensive cells which alert your immune system if there are viruses or other infectious agents on the skin.
The middle layer sandwiched between the outer and deep inner layer of skin is called the dermis. This layer adds strength and elasticity to the skin, largely thanks to fibres known as collagen and elastin.
Blood vessels are also prominent in this layer, helping to regulate body temperature. If you are too hot, it will increase blood flow to the skin so that heat can be released – this is the reason why when you exercise, your skin may redden. When you are too cold, it will restrict blood flow to prevent heat loss, the reason why your skin can look pale, white or takes on a blue tinge when you are cold.
There are also a plethora of nerves in this layer too, all of which transfer messages to the brain about touch, temperature and pain.
The dermis is also jam-packed with hair follicles and glands. Sweat glands, for example, help regulate your internal temperature. Apocrine glands develop during puberty and produce the scented sweat that is linked to sexual attraction. The sebaceous glands secrete sebum, the oil-like substance that lubricates hair and skin.
The third layer of skin is deeper still and is often described as a seam of fat laid down as a fuel reserve in times of food shortage. It also works as an insulating layer, as well as a malleable cushion that absorbs knocks and falls.
The complexity of the skin as an organ means we are yet to fully understand why some people’s skin reacts differently to agents and chemicals. This is why it makes sense to consult with a dermatologist. They have an in-depth specialist knowledge of the skin and can relate these to you and how your skin has a tendency to react to different agents and environments.