Skin is known as the largest and very important organ of the human body. The major task of skin is serving as a barrier to the outside world and protect the human body from harmful environmental components. Skin doesn't let the undesired germs penetrate inside.
Thus, it's a common knowledge skin is a protective organ having a metabolism of its own. But at the same time it is considered to be rather sensitive to different environmental influences, such as cold, temperature, etc. Skin is composed of three layers: epidermis, dermis and hypodermis. It goes without saying the mentioned layers have different components and functions.
Speaking about skin functions of epidermis it's impossible not mention that it has two principal assignments: it protects the body from the harmful affect of the sun and infections, it can prevent body from loosing water. It is evident for the majority of people who take care of their health that sun produces a great amount of light and heat which isn't always good. It produces some unbeneficial ultraviolet rays completely invisible for people. It is important that to carry out skin functions epidermis includes stratum corneum (it reflects the radiation from the skin surface) and melanin (it absorbs part of the radiation).
During our lives people naturally lose water (particularly by constant evaporation through the skins). But it is exceptionally important to prevent losing much of this water because it makes up approximately 75% of skin basal layer weight. Thus, stratum corneum is one of the most important barriers to control the loss of moisture and against the outside environment. It is at the same time both flexible and tough. It is significant that epidermis includes white blood cells inside which help to carry out such skin functions as capturing and destroying bacteria invading the epidermis.
Skin functions of dermis are pretty essential as well. For example, this skin layer gives a mechanical protection to the body from knocks and bumps. The important role is this skin function plays the collagen. Dermis also provides nutrients and oxygen to all human body cells via blood in the vessels, removes waste products of metabolism from epidermis (they are carried away in the blood), holds all skin structures together and as a result - provides shape and hold to the body.
Finally, it's worth admitting there are some special organs and nerve endings in the dermis which carry out some outstanding and specific skin functions: regulation of the human body temperature (through control of sweating and blood flow), provision of skin sensations, pain, heat, cold and touch. Temperature regulation is considered to one of the major skin functions. Skin has a direct influence of the temperature of the whole body though both narrowing or widening of skin blood vessels and liquids secretion over the skin glands, storing fat and make vitamin d. Skin has also a function of sense communicating with environment. It is carried out by means of great number of receptors (for example, warmth and cold ones) and intraepithelial nerve endings.