Question

Most radiosensitive tissue of the body is
A. Bone marrow
B. Platelet
C. Nervous tissue
D. Lymphocyte

Answer 1

Hint:-The relative susceptibility of cells , tissues , organs, or animals to the adverse impact of ionising radiation is radiosensitivity. In general, cell radiosensitivity has been found to be directly proportional to the cell division rate and inversely proportional to the degree of cell differentiation. In short, this means that the most at risk from radiation is actively dividing cells or those that are not fully mature.

Complete Answer:-Among the most radiosensitive cells in the body are the blood-forming cells of the bone marrow. The natural replacement of circulating blood cells is disrupted if a significant number of those cells are destroyed, which may happen when intense irradiation of the entire body happens. As a consequence, the number of blood cells may become depressed, and inflammation, haemorrhage, or both may eventually follow.
A health image referred to as radiation sickness or acute radiation syndrome is the signs and effects arising from intensive irradiation of a significant part of the bone marrow or gastrointestinal tract. In the first few hours following irradiation, early symptoms of this syndrome usually include lack of appetite, fatigue, and vomiting, accompanied by a symptom-free period that continues until the main course of the disorder.

From these discussions we can conclude that Bone marrow is the most radiosensitive tissue of the body. Therefore the correct answer is option (A).

Additional information: It was believed for several years that radiation disease was permanent after a fatal dosage had been delivered. Bone-marrow cells delivered shortly after irradiation have since been discovered to allow a person to survive an otherwise fatal dose of X-rays, as these cells migrate to the marrow of the irradiated recipient, where the blood-forming tissues proliferate and repopulate. Under these conditions, even in histo-incompatible people, bone-marrow transplantation is possible since the irradiated patient has lost the capacity to produce antibodies against the foreign cells injected. However, the transplanted tissue may ultimately be discarded after a duration of several months, or it may produce an immune response against the irradiated host, which can also be lethal.

Note:- Bone-marrow cell transplantation has been helpful in avoiding radiation casualties among reactor accident patients, such as those wounded in 1986 at the Chernobyl nuclear power plant in Ukraine, then in the Soviet Union. However, it should be remembered that it is not yet possible to use cultured or preserved marrow cells for this purpose.