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Electrical phenomena play an important role in many physiological processes that occur in living organisms. In addition may influence, in bad or good, their operation.
First we have to mention the propagation of nerve impulses.
Nerve fibers has in composition a cylindrical membranes containing inside a conducting fluid (an electrolyte), and outside beingall surrounded by a fluid conductor. By a similar mechanism which is manifested in the voltaic cell, between the two fluids is maintained a potential difference of approximately 0.1 V.
Due to the nature of the mechanism of propagation of electrical nerve impulses, human body is very sensitive to the action of electrical outside currents.
A current of 10 mA order can cause strong muscle contractions , uncontrolled, accompanied by pain.
At 20 mA, the human body manifests breathing difficulties and the person can not let go of the conductor that produced electric shock.A current of 100 mA can be fatal because affects the nerve processes related to heart function :uncoordinated and uncontrolled contraction of heart muscle are produced , a phenomenon known as the fibrillation of the heart.Heart blood pumping activity is completely disorganized and the effect can be fatal. This effect can be used in beneficial way: in emergencies practice, in case of cardiac arrest. Devices are used for application of high tension (length of time very small) targeting restore of normal operating mechanism of the heart.
just some pointer'sElectric current is capable of producing deep and severe burns in the body due to power dissipation across the body's electrical resistance. Tetanus is the condition where muscles involuntarily contract due to the passage of external electric current through the body. When involuntary contraction of muscles controlling the fingers causes a victim to be unable to let go of an energized conductor, the victim is said to be "froze on the circuit." Diaphragm (lung) and heart muscles are similarly affected by electric current. Even currents too small to induce tetanus can be strong enough to interfere with the heart's pacemaker neurons, causing the heart to flutter instead of strongly beat. Direct current (DC) is more likely to cause muscle tetanus than alternating current (AC), making DC more likely to "freeze" a victim in a shock scenario. However, AC is more likely to cause a victim's heart to fibrillate, which is a more dangerous condition for the victim after the shocking current has been halted.
Human body can easily bear electrical current of 1 milliampere passing through its body without appreciable risk or damage. However, as the amount of current increases the body may suffer different type of damages including death or electrocution. The physiological effects of electrical shock include the following.
- Burns to parts of the body due to heat generated by electricity.
- upsetting of the timing of operations of heart valve. If not treated in time this can lead to death.
- Damage to nervous system causing loss of nervous control.
- When the current passes through brain it can lead to unconsciousness and permanent damage to the brain.
In addition to the effect of electrical, the heat light and pressure generated by electrical faults are also major cause of injury and death.
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