Question

Radiation has different effects on different cells. Explain the consequences of radiation damage to somatic cells and to germ line cells.

  

The words here that are important to note are significant dose

  

Answer 1

Radiation has different effects on different cells. The consequences of radiation damage to somatic cells and to germ line cells are significant.

Firstly, SOMATIC EFFECTS are those suffered by the exposed person, whereas HEREDITARY EFFECTS don’t appear until later generations are born. Also, in a human, the somatic cells contain twenty-three pairs of chromosomes. (This number varies with different species of animals.) The sperm cells in males and egg cells in females (both are called germ cells) contain half the usual number of chromosomes. In humans, these germ cells contain 23 single chromosomes. The germ cells are produced in the gonads, a term for the male testes or female ovaries.

As for long term Somatic effects ,somatic cells are all cells of your body other than the reproductive cells. They can be damaged in a variety of ways, such as by chemical, biological and physical agents or by ionising radiation. The effects of the damage from ionising radiation can be short-term or long-term depending on the means and severity of the exposure. The most important long-term effect of radiation exposure is an increased chance of getting cancer.Acute exposures are those delivered in a short time, i.e., within a day. Chronic exposures are those delivered over a long period of time, i.e., weeks and months.

As for effect of radiation on cells, the tissues in our bodies most affected by an acute radiation dose are whose cells are most rapidly reproducing. These self-renewal tissues are the skin, the blood-forming tissues, the gonads and the digestive system lining (called the gastrointestinal tract or GI tract.)

In developing embryo and foetus, the most radiosensitive tissue of the human body is the developing embryo or foetus. A lot of complex things have to happen at the right time and in the right order, and there is much opportunity for outside agents to make things go fubar. Briefly the development of the human conceptus can be divided into three phases:

1. the pre-implantation period lasting from fertilisation until implantation of the embryo into the uterine wall;

2. the phase of major organ formation, which extends in man (well, woman actually) until about the 8th week after ovulation;

3. the phase of foetal development, continuing on until birth.

Much of the information about effects of prenatal irradiation comes from observations of laboratory animals. The major effect of irradiation during the first phase is death of the conceptus, but those that survive appear unimpaired with respect to morphology (shape), size, long-term survival and reproductive fitness. In humans the effect would simply be noted as a temporary failure to conceive.

In short the risks include: mortality, malformations, severe mental retardation, childhood cancer, etc.Radiation injury is treated by conserving and augmenting the blood constituents and by assisting the body's anti-bacterial mechanisms. Localised doses cause much less damage than whole-body doses of the same size.

Genetic Effects in Mouse Spermatogonial Stem Cells.The most comprehensive genetic data are those on specific locus mutations in mouse male germ cells, stem spermatogonia. Death may also result if cell reproduction ceases in parts of the body where cells are continuously being replaced at a high rate (such as the blood cell-forming tissues and the lining of the intestinal tract). A very high dose of 100 gray (10,000 rad) to the entire body causes death within twenty-four to forty-eight hours; a whole-body dose of 2.5 to 5 gray (250 to 500 rad) may produce death within several weeks.

Finally, to sum up it can be stated that somatic cells and germ in line cells both undergo significant impacts, germ in line cells can on one hand lead to mortality, malformations, etc and somatic ones too can lead to the above mentioned circumstances.