CLINICAL MEDICINE

Detailed explanation-1: -Immature (undifferentiated) hematopoietic cells that have divided (proliferated) from stem cells are highly sensitive to radiation and die due to a small amount of radiation more easily than differentiated cells.

Detailed explanation-2: -Bone marrow is extremely vulnerable to damage caused by radiation therapy (5). Hence, bone marrow suppression is one of the most important side effects of radiotherapy.

Detailed explanation-3: -Lymphocytes (white blood cells) and cells which produce blood are constantly regenerating, and are, therefore, the most sensitive. Reproductive and gastrointestinal cells are not regenerating as quickly and are less sensitive. The nerve and muscle cells are the slowest to regenerate and are the least sensitive cells.

Detailed explanation-4: -It is most generally held that lymphoid tissue is the most radiosensitive of all the hematopoietic tissues. The subject of comparative sensitivity of the various marrow cell lineages has been reviewed in recent years.

Detailed explanation-5: -To direct irradiation the cells of the bone marrow proved highly radiosensi-tive, the erythroblasts slightly more than the myeloid cells. Within each series of cells, the youngest forms were the first to disappear, while the older ones dis-appeared with increasing doses.