Structure and Functions of Skin

Structure and Functions of Skin

Structure and Functions of SkinSkin, the largest organ in the human body is wrongly considered to be giving very little in return while demanding a lot of attention like bathing, shaving, scrubbing, spa treatment etc. The skin is an absolute essential part of our body.

The skin performs many functions:

Produces Vitamin D
Helps regulate our blood pressure
Activates the male sex hormone, testosterone
Retains moisture

The complex nervous system of the skin detects touch, heat, cold and pain and passes the information to the brain. The skin protects us from a variety of deadly intruders, namely the bacteria that live on its surface or invade it from the outside.

The skin comprises 3 layers:

The outer epidermis.
The middle dermis.
The inner subcutaneous tissue.

The epidermis is thin in most areas on the body. When we burn our finger, we can see the epidermis as the transparent tissue on top of the blister. There is no blood supply in the epidermal layer and its cells get their nourishment by diffusion from below.

The cells on the epidermis cannot survive for long due to the atmosphere. Therefore, millions of cells see their way out when we bathe or rub. Just like a snake shedding its skin, epidermis also sheds itself. This change of skin happens once every 27 days. Everyday, new cells form at the innermost part of the epidermis and make their way up to the outer layer, changing from jelly-like cellular material to harder keratin.

The dermis or the middle layer of the skin is a strong but elastic case that holds sweat glands, nerves and nerve endings, hair follicles, blood vessels and sebaceous glands.

It is very interesting to know about the intricate network of blood vessels in the dermal layer of the skin. It enacts different roles (behaves differently) under different conditions. For instance, when we exercise on a hot day, the blood vessels dilate, causing flushing. The skin radiates heat to the outside to counter this. On a cold day, the blood vessels shut down directing blood to the interior of your body, so you go pale.
Emotions are also controlled by blood vessels. When you are angry you flush because the blood vessels of your face open up. Fear closes them and you develop cold feet.
Normally, the sweat glands produce half a kilo of water that we lose as sweat, but on a hot day or when you indulge in hectic activity, the loss of water by way of sweat is about 6 kilos.

The skin has a complex air-conditioning system. There are about 2 million fat or sebaceous glands in the skin spread out all over the body surface. Each sebaceous gland is a tightly coiled little tube located in the depth of the dermis with a long duct extending to the surface. The total length of these tiny ducts is about 9 km. The sebaceous glands secrete a semi liquid oil. They are attached to the hair follicles and serve as lubricants to the hair and the skin around it. The sebaceous glands must have been of great help to our hairy ancestors of the primitive times, by increasing the heat retaining capacity. Today they are more of a worry than help because they are primarily responsible for the clogging of the hair follicles, for black heads, pimples and the teens’ most dreaded acne.

Hair follicles, numbering about 10/sq cm, consist of a bulbous root deep inside beneath the skin, and a shaft going up to the surface. Men and women have the same number of hair follicles, but women have light colored and fine hair that it is almost invisible. Hair follicles produce hair all the time, extruding dead cells above the surface.
The skin has an intricate nerve network too.

The skin has millions of cells called ‘melanocytes’ which are responsible for the production of the most important pigment ‘melanin’. Melanin determines the color of one’s eyes, hair and skin. Protective tan from excessive exposure to the sun is formed by melanin. When melanin shows a concentration on the skin, it is called freckles.

As you grow older, your skin becomes thinner and transparent as your veins start to show. The fat deposits just below the surface of the skin decreases and wrinkles begin to appear. The skin loses its elasticity, so sagging occurs, especially beneath the eyes, around the lips etc.

Care should be taken to give a lot of attention to your skin in your earlier years so that you can delay the formation of fine lines and wrinkles that appear as a sign of aging. You can look and feel young when you have a smooth, clear and tight skin. Caring for your skin from an early age will help protect it from the harmful effects of pollution and conditions like acne and eczema.


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