Action of an electric current on an organism of the person

On a degree of danger to the person electric current, according to the researches which have been hold by U.N.O., is on the fifth place among 30 various factors threatening to human life (more danger is represented by: smoking, alcohol, the transport and the weapon). Persons in the age of 20-30 years more suffer - 65,5 % injured. Older than 30 years the number of injured - 12,5 %and under 20 years - 22 %. For last years the number of defeats by an electric current of women has increased.

Danger of influence of an electric current on an organism of the person is aggravated also with the fact, that he is not perceived by his organs of sense on a distance, and is felt only at the moment of the touch to current-carrying parts.

The electric current, influencing on an organism of the person, can cause lesions, the degree of which depends on the kind and amperage of current, its duration, and also a way of passage through the body.

The person starts to feel influence of an flowing altering current of industrial frequency through him of 50 Hz, amperage 0,6-1,5 mA and constant current 5-7 mA. At increasing of the current which is flowing through the body of the person, his influence is increasing and at the value of an alternating current of industrial frequency 10 mА (60-80 mA of constant current) involuntary reduction of muscles (spasm) of arms appear, therefore the person cannot unclench his fist which holds a current-carrying part, i.e. he can't be released with himself from contact to a current carrying part. At the large values of a current hands are paralyzed, breath makes difficult. More current, it's more likely to get broken work of lungs and the heart. At current of industrial frequency 100 mA and more work of lungs and the heart stops, lesion comes in 2-3 seconds from the beginning of influence of current.

Amperage of the current flowing through the body of the person, is determined by the enclosed voltage and the total resistance of the body. The greatest resistance to an electric current renders an integument, and resistance of tissues of internal organs (muscular, adipose, spinal cord and brain, blood, etc.) in comparison with the skin isn't enough.

Resistance of a body of the person in a strong degree depends on a status of a skin. Cuts, scratches, grazes (damage of a horn layer), humidifying and allocation of sweat, pollution by various substances (the metal or coal dust, scale, etc.) can reduce resistance of a body of the person up to the value close to the value of his internal resistance.

Resistance of a body of the person depends on the enclosed voltage, amperage, the kind and frequency of current, and also on duration of its passage through the body of the person. With increasing in the voltage enclosed to a body of the person, resistance of the skin, and consequently, resistance of the body sharply decrease due to electric breakdown of a horn layer of a skin.

With increasing in a current and duration of its passage through the body of the person resistance decreases, as local heating of the skin increases that leads to expansion of its vessels and increasing of perspiration.

The alternating current, in particular current of frequency of 50 Hz, represents the big danger, than a direct current of the same force.

At calculations resistance of a body of the person to a current of industrial frequency count constant and equal R = 1000 Ohm.

Passing through an organism of the person, an electric current makes thermal (burns of separate sites of a body, heating blood vessels, nerves, etc.), mechanical (break of fabrics), chemical (electrolysisblood and other organic liquids) actions, at the same time influences hit biologically, breaking its viability, In a muscular fabric, it is especial at reduction of muscles of heart and easy, in fabrics of the central and peripheral nervous system and in other fabrics there are biocurrents which break biological balance that results in various outcomes. The electric current, passing through biological fabrics, causes ionization of their atoms, changes potential of cells and fabrics that results in infringement of their normal functioning.

Дата добавления: 2015-10-21