Ultraviolet rays have very high energy.In this connection, in the process of their absorption in the molecular and atomic structure of significant changes.The absorbed energy, which identified the ultraviolet rays can be used to break the weak bonds of protein molecules.This process is called photolysis.His flow is accompanied by the release of active substances under the influence of medium-wave ultraviolet irradiation.
Shortwave effects provokes the denaturation of the protein polymers that are losing their activity, precipitate.Ultraviolet rays have a particular impact on the DNA molecule.Under the influence of observed violation of DNA doubling and cell division.At the same time, ultraviolet rays cause oxidative degradation in protein structures.This leads to cell death.But damaged kernels have the ability to recovery (dark repair).This is possible under the influence of long wavelength UV and visible light energy.In this process, specific enzymes are involved.
The dark and photo-reactive repair belong to the category of protective and adaptive reactions.They laid the nature of the human body and provide protection from the effects of UV radiation.
medium-impact helps to activate the processes of formation of vitamins.Thus, the ultraviolet rays are converted pro-vitamins contained in the skin, into vitamin D. Penetrating only one-tenth of a millimeter, exposure ensures the formation of a large amount of energy in comparison with other electromagnetic waves of infrared and visible spectrum.
photolysis and denaturation are in spinous layer of the skin.With this done histamine release acetylcholine, biogenic amines.These compounds provoke the development of erythema.It occurs after 2-8 hours.Protein decomposition products contribute to the expansion of blood vessels, the migration of white blood cells, swelling of the skin.All these phenomena are complicated by irritation of skin receptors, the receptors of the internal organs, with the emergence of neuroreflex reactions.Decomposition products diverge through the bloodstream, providing humoral influence.Ultraviolet radiation in the medium wave range provokes skin aseptic inflammatory reaction.By the second day it reaches its maximum.On the seventh-ninth day of the inflammatory reaction occurs, instead appears tan.Short-wave radiation will provoke erythema, leaving a mild pigmentation.
Maximum chromogenic influenced by long-wave UV rays.In melanoblast located in the basal layer of the epidermis, from tyrosine, and the decay products adrenaline dihydroxyphenylalanine formed melanin.His (melanin) giant molecules prevent ingress deep dermis fragments of protein molecules destroyed by UV radiation.In addition, the melanin molecules absorb infrared rays and visible spectrum.Thus, the skin is protected from overheating and burning.In the areas of influence of ultraviolet rays increases the blood flow and lymph flow, improves the regeneration of cover, increases the synthesis of collagen fibers.When intense erythema flowing amplified chronic and acute inflammatory processes occurring.
UV exposure is widely used in cosmetology.So, in the solarium, and even get a nice tan.It uses long-wave rays, and on shortwave and medium radiation in tanning salons are filters.
It should be noted that excessive sun exposure can cause premature aging, a decrease in the elasticity of the skin.Furthermore, it may be activated by the formation of free radicals that contribute to cancer.
to determine the boundary between "harmful" and "helpful" Sun UV Index is used.This parameter indicates the level of radiation in the world.
