Electric current is very similar to the flow of water, only instead of its molecules moving down the river, charged particles move along a conductor.
In order for electric current to flow through the body, it must become part of an electrical circuit.
DC and AC
The degree of damaging effect of electric current on the human body will depend on its type.
If the current flows in only one direction, it is called direct current (DC).
If the current changes direction, it is called alternating (AC). Alternating current is the best way to transmit electricity over long distances.
AC with the same voltage as DC is more dangerous and causes worse consequences. The action of electric current on the human body in this case can cause the effect of "freezing the muscles of the hand." That is, there will be such a strong muscle contraction (tetany) that a person will not be able to overcome.
Ways to gethit
Direct contact with electricity will occur when someone touches a conductive part, such as a bare wire. In private homes, this is possible in rare cases. Indirect contact occurs when there is an interaction with any equipment or electrical appliance, and due to a malfunction or violation of the rules of storage and operation, the device case can be shocked.
Fun fact: Why are birds never electrocuted from sitting on cables?
This is because there is no voltage difference between the bird and the power cable. After all, it does not touch the earth, like any other cable. Hence, the voltage of the bird and the cable coincide. But if suddenly the bird's wing touches, say, a metal winding on a pole, an electric shock will not take long.
The force of impact and its consequences
Let's consider the effect of electric current on the human body briefly:
| Electric current | Effect |
| Below 1 mA | Not perceived |
| 1mA | Tingling |
| 5mA | A little shock. It doesn't hurt. A person will easily let go of the current source. Involuntary reaction may result in indirect injury |
| 6-25 mA (female) | Painful shocks. Loss of muscle control |
| 9-30 mA (Male) | "Unreleased" current. The person can be thrown away from the power source. A strong involuntary reaction can lead to involuntary injury |
| 50 to 150 mA | Severe pain. Stopping breathing. Muscle reactions. Possible death |
| 1 to 4, 3 A | Fibrillation of the heart. Damage to nerve endings. Probable death |
| 10 A | Cardiac arrest, severe burns. Death most likely |
When current flows through the body, the nervous system experiences an electrical shock. The intensity of the impact depends mainly on the strength of the current, its path through the body, and the duration of contact. In extreme cases, shock causes interruptions in the normal functioning of the heart and lungs, leading to unconsciousness or death. The types of action of electric current on the human body are divided depending on what complications the current caused to the body.
Electrolysis
It's simple: an electric shock will contribute to a change in the chemical composition of blood and other fluids in the body. Which will further affect the operation of all systems as a whole. If a direct current passes through the tissues of the body for several minutes, ulceration begins. These ulcers, while not usually fatal, can be painful and take a long time to heal.
Burns
The thermal effect of electric current on the human body manifests itself in the form of burns. When an electric current passes through any substance that haselectrical resistance, heat is released. The amount of heat depends on the power dissipation.
Electrical burns are often most noticeable near the site of current entry into the body, although internal burns are quite common and, if not fatal, can cause long-term and painful injury.
Muscle cramps
Irritating and stimulating living tissues, an electric discharge enters the muscle, the muscle unnaturally and convulsively begins to shrink. There are various disturbances in the work of the body. This is how the biological effect of electric current on the human body is manifested. Prolonged involuntary muscle contraction caused by an external electrical stimulus has one unfortunate consequence when the person holding the electrical object is unable to release it.
Respiratory and cardiac arrest
The muscles between the ribs (the intercostal muscles) must repeatedly contract and relax in order for a person to breathe. Thus, prolonged contraction of these muscles can interfere with breathing.
The heart is a muscular organ that must constantly contract and relax in order to perform its function as a blood pump. Prolonged contraction of the heart muscles will interfere with this process and lead to its stop.
Ventricular fibrillation
The ventricles are the chambers responsible for pumping blood from the heart. When an electric shock occurs, the ventricular musculature will undergo irregular, inconsistenttwitching, as a result, the "pumping" function in the heart will stop working. This factor can be fatal if not corrected in a very short period of time.
Ventricular fibrillation can be caused by very small electrical stimuli. A current of 20 μA passing directly through the heart is sufficient. It is for this reason that most deaths are due to ventricular fibrillation.
Natural Defense Factors
The body has its own resistance to the actions exerted by electric current on the human body in the form of skin. However, it depends on many factors: on the part of the body (thicker or thinner skin), skin moisture and the area of the body that is affected. Dry and wet skin have very different resistance values, but are not the only aspect to consider when dealing with electric shock. Cuts and deep abrasions contribute to a significant reduction in resistance. Of course, the resistance of the skin will also depend on the power of the incoming current. But still, there are many cases when, due to the high resistance of the skin, a person, in addition to an unpleasant electric shock, did not receive a single electrical injury. The action of electric current on the human body did not bring any undesirable consequences.
How to prevent electric shock
Prevention of electric shocks, especially in everyday life, is a prerequisite for a safe life. Insulation is used for any current-carrying parts. For example, cables are insulated electrical wires, allowing them to be used without the risk of any electrical shocks, and boxed light switches prevent access to live parts.
There are special low-voltage devices that provide additional protection against electric shock.
RCDs (residual current devices) can provide additional electrical safety. The effect of electric current on the human body in this case will be zero. This device, in the event of an unwanted leakage, will turn off a damaged section of electrical wiring or a faulty electrical appliance in a few seconds, which will not only save a person from receiving current, but also protect them from fire.
Difavtomat, in addition to the features described above, has protection against overloads and short circuits.
It is important to ensure that any electrical work done in the home is done by a qualified electrician who has the technical knowledge and experience to ensure the job is safe.
Power of electricity in living beings
Electrochemical energy is produced in every cell of every living organism. The nervous system of an animal or human sends its signals through electrochemical reactions.
Almost every electrochemical process and its technological application plays a role in modernmedicine.
The film about Frankenstein uses the specific effect of electric current on the human body. The power of electricity turns a dead man into a living monster. Although the use of electricity in such a context is still not possible, electrochemical forces are necessary for our bodies to function. Understanding these forces has greatly helped the development of medicine.
The action of electric current: the first experiments
From 1730, after Stephen Gray's experiments in transmitting electric current over a distance, over the next fifty years, other researchers discovered that the touch of an electrically charged rod could cause the muscles of dead animals to contract. A typical example of the influence of electric current on a biological object is a series of experiments by the Italian physician, physicist and biologist Luigi Galvani, who is considered one of the founding fathers of electrochemistry. In these experiments, he sent an electrical current through the nerves to the frog's leg, and this caused muscle contraction and movement of the limb.
At the end of the nineteenth century, some doctors began to study the effect of electric current on the human body, but not dead, but alive! This allowed them to make more detailed maps of the muscular system that were previously unavailable.
Electrotherapy and tricks
During the eighteenth and early nineteenth centuries, electric current was used everywhere. Doctors, scientists and charlatans, not always different from each other, used electrochemical shocks to treat any disease, especially paralysis andsciatica.
At the same time, specific shows appeared, both terrifying and leading to wild delight. The essence of these was to revive the corpse. Giovanni Aldini succeeded in this matter, who, with the help of an electric current, made the dead man "come to life": he opened his eyes, moved his limbs, and rose.
Current in modern medicine
The effect of electric current on the human body, in addition to treatment (for example, physiotherapy), can also be used to detect he alth problems early. Special recording devices now turn the body's natural electrical activity into charts, which are then used by doctors to analyze abnormalities. Doctors now diagnose heart abnormalities with electrocardiograms (ECGs), brain disorders with electroencephalograms (EEG), and loss of nerve function with electromyograms (EMGs).
Life through electric current
One of the most dramatic uses of electricity is defibrillation, which is sometimes shown in films as "starting" a heart that has already stopped working.
Indeed, triggering a short burst of significant magnitude can sometimes (but very rarely) restart the heart. However, more often defibrillators are used to correct the arrhythmia and restore its normal state. Modern automated external defibrillators can record the electrical activity of the heart, determine fibrillationventricles of the heart, and then calculate the amount of current needed for the patient based on these factors. Many public places now have defibrillators so that the electric current and its effect on the human body in this case will prevent deaths caused by heart dysfunction.
It should also be mentioned artificial pacemakers that control the heart beats. These devices are implanted under the skin or under the muscles of the patient's chest and transmit electrical current pulses of about 3 V through the electrode and the heart muscle. This stimulates a normal heart rhythm. Modern pacemakers can last up to 14 years before they need to be replaced.
The action of electric current on the human body has become commonplace, and not only in medicine, but also in physiotherapy.
