The biological effect of radiation on humans

The biological effect of radiation on a person is the ionization of the cells of the tissues of his body and the appearance of radiation sickness. The course of the disease will depend on many factors: from the area affected, from the dose of ionizing radiation, from the time during which this dose is received.

Ionizing radiation

When high energy particles, or photons, pass through a substance, they form pairs of charged particles, called ions, in their path. Therefore, ionizing radiation is considered dangerous. The biological effect of radiation has a greater effect on living matter. Live tissue - these are cells that are constantly updated, this is a dynamic process. And for him, the ionizing irradiation turns out to be painful doubly.

Part of the radiation damage is associated with mechanical damage to molecular structures, for example, chromosomes. In part - with the chemical processes that take place with the liberated radicals. Since a person consists of 75% water, the first radiation radiation absorbs water cells, forming free radicals such as OH, HO2, H. Subsequently, chain reactions occur in the oxidation of protein molecules by these radicals. Further, there are functional changes in the biological patterns of cell life.

In the cells the following changes occur:

• The division mechanism and the chromosomal apparatus of the damaged cell are damaged;
• The process of cell renewal and differentiation is blocked;
• The process of proliferation and tissue regeneration is blocked.

Most of all, the biological effect of radiation affects the constantly renewing cells of the bone marrow, spleen, sex glands, etc.

Acute radiation sickness

A very high dose of ionizing radiation (more than 600 rad) leads to rapid death of a person (if no treatment is provided). At a dose of 400-600 rad, about 50% of people die. An acute radiation sickness begins, in which the hematopoietic system (red bone marrow) breaks down and dies and the body's defense system ceases to function.

The first week of acute radiation sickness is asymptomatic - this is the so-called latent period of the disease. Then comes a breakdown, immunity fails, all chronic diseases begin to worsen, and new infections appear. Approximately by the fourth week, anemia develops, the blood ceases to collapse, the risk of bleeding increases.

Today's level of medicine can save people who received a dose of ionizing radiation up to 1000 rad. Previously, the biological effect of radiation in such quantities was not amenable to treatment. Radiation disease is an extreme degree of defeat. Smaller doses can cause leukemia and various malignant tumors.

Sources of radiation and types of radiation

A person can receive a hazardous dose of radiation from a passing radiation cloud or from the contaminated surface of buildings, structures, land. This is called external irradiation. Internal irradiation occurs when a person inhales an infected aerosol (inhalation hazard) or consumes contaminated food and water. Radioactive substances can get on the skin and clothing. Such an irradiation is called a contact irradiation.

Biological effects of radiation can cause the following effects:

• Somatic-stochastic. They are difficult to detect and can not be manifested for decades.
• Somatic. They affect only the irradiated person, they do not affect the offspring.
• Genetic. Sexual cellular structures of irradiated people are violated, which will affect the offspring that appears with congenital deformities and mutations.

The degree of irradiation depends not only on the dose, but also on the time of exposure to radiation. A dose of 300 rad, received within a few months, will not lead to illness, but at one time can lead to serious consequences. Acute radiation sickness can develop with a single dose of 100 rad.