Skin is the largest organ in our body and is a part of the integumentary system. In an average human, the skin has a total surface area of about 1.5 to 2.0 sq.m. For cosmetic reasons, skin is one of the most pampered organs in the human body. A clear, glowing skin is always admired for its appearance. A healthy skin performs various vital body functions.
Layers of the Skin
The human skin is made up of three layers - the outermost epidermis, followed by dermis, and the innermost hypodermis. The epidermis is made up of keratinocytes, melanocytes, Langerhans cells, and Merkel cells. This layer lacks blood vessels, and so, it gets nourishment from the superficial layers of the dermis.
The layer beneath the epidermis is called dermis, and this layer is attached to the former by a basement membrane. The dermis has nerve endings, blood vessels, hair follicles, sebaceous glands, and lymphatic vessels. The hypodermis that lies beneath the dermis serves the purpose of attaching the other skin layers to the underlying bones or muscles.
It is this layer, that contains a major part of the body fat. While epidermis plays a vital role in the function of maintaining body temperature, and in providing a waterproof outer covering; the dermis with connective tissues, protects the body from stress and strain. The hypodermis with fat provides insulation, and also cushions the inner parts.
Protects the body
As the skin is exposed to the environment, it comes into contact with pathogens and other toxins. The Langerhans cells in the skin are responsible for destroying such pathogens. The skin protects the body from radiation and chemicals.
It is a common fact that the skin is responsible for the sensation of touch. This is because of the presence of numerous nerve endings, that react to sensations, like pressure, pain, heat, and cold.
One of the important functions of the skin is maintaining the normal body temperature. This is accomplished with the help of sweat glands, that expel waste products as well as water, so as to cool the body.
The fat in the dermis provides insulation from cold. Even dilation of the small blood vessels in the skin results in cooling of the body. Likewise, constriction of these blood vessels reduce heat loss from the body.
The skin also prevents loss of water and nutrients from the body, through evaporation, as it acts as a barrier.
The skin can also absorb small amounts of oxygen, carbon dioxide, and nitrogen. Some medicines are meant for absorption through the skin only.
Produces vitamin D
While the skin stores water and lipids, this organ can also synthesize vitamin D, when it is exposed to sunlight.
The skin performs excretion of urea, water, uric acid, and ammonia, in small amounts, through the sweat.
These are some of the main functions of the skin. Apart from the mentioned ones, the skin can also communicate feelings through blushing and paling. Changes in skin conditions can be a symptom of certain medical conditions. In short, the skin is undoubtedly, an important organ of the human body.