An electric shock occurs when an electrical current from an outside source flows through the tissues of a human body. A shock can be caused by static electricity or by contact with a power source such as a battery or an electrical line. The human body can be damaged by electric shock, as the flow of current can disrupt the normal functioning of the nervous system or, at higher levels, cause severe burns as it passes through the body. Electric shock can also be used as a medical treatment, typically to correct problems with the functioning of the body’s nervous system.
Humans are quite sensitive to electricity, in no small part, because our nerves rely on electrical impulses to carry information. Even the amount of current generated by a 12-volt battery is usually perceptible by the more sensitive parts of the nervous system. For an electrical current to be perceived as a shock, however, it will typically need to be either more abrupt, as in the sudden discharge of the body’s static electricity, or more powerful, like contact with an electric fence or household current.
The role that electrical impulses play in the functioning of the nervous system is at the root of one of the main dangers from an electric shock. Nerves use electricity to transmit information. A sufficiently large dose of electricity can easily overcome the normal electrical charge of the nervous system, and can leave nerves locked in an activated state. This process can lead to twitching in the muscular system or, more seriously, can disrupt the normal rhythm of the heart.
A further source of danger from electric shock stems from the fact that the human body is made up largely of water and is therefore an adequate, though not ideal, conductor of electricity. This fact allows electricity to pass through the body but ensures that, when it does, it causes damage, as waste heat is generated when current overcomes the body’s natural resistance. When a person is exposed to a very powerful electric current, this heat is quite intense and will cause serious burns throughout the body, damage that can often prove fatal even if the initial disruption to the nervous system is not.
Electric shock can be used to heal the body as well. Electroconvulsive therapy relies on electrical shocks to reset the neural state of the brain, which may, over time, cause neural problems that arise from unhealthy chain firings of particular networks of neurons to dissipate. An electric shock can also be used to restart a human heart or correct the improper beating of a heart in which the the correct rhythm has been disrupted.