Which organ is most sensitive to radiation exposure?

The bone marrow is recognized as the organ most sensitive to radiation exposure. This sensitivity stems from the high turnover rate of the hematopoietic stem cells found in the bone marrow, which are responsible for producing blood cells. When exposed to radiation, these rapidly dividing cells are more likely to sustain damage, which can lead to significant health issues, such as a decrease in blood cell production, compromised immune function, and increased risk of leukemia.

In contrast, while other organs like the liver, skin, and thyroid have their own response to radiation, they do not exhibit the same level of vulnerability as the bone marrow. The liver has a remarkable capacity for regeneration, the skin can repair itself through various mechanisms after damage, and the thyroid, though sensitive to certain types of radiation (especially iodine-131), does not have the same risk profile as bone marrow in terms of acute radiation syndrome. Thus, the bone marrow's critical role in the body and its high cellular turnover make it the primary organ of concern when evaluating radiation sensitivity.