Which cell type is among the most radiosensitive?

Which cell type is among the most radiosensitive?

• A. Nerve cells
• B. Muscle cells
• C. Epithelial cells
• D. Lymphocytes

Answer: (D)

Radiosensitivity is highest in cells that are actively dividing and not highly differentiated. This idea comes from the Bergonie and Tribondeau principle, which says that undifferentiated, proliferating cells have the greatest sensitivity to radiation and also the most potential to undergo mitotic arrest or apoptosis after DNA damage. Lymphocytes fit this pattern perfectly. They are small, relatively undifferentiated white blood cells that circulate and divide rapidly in response to immune needs. Because they have a high rate of division and a limited ability to repair radiation-induced DNA damage before triggering cell death, they are extremely vulnerable to ionizing radiation. This is why lymphocytes are among the most radiosensitive cells in the body, and why radiation exposure can quickly cause a drop in lymphocyte numbers. In contrast, nerve cells and muscle cells are mature and largely non-dividing, so they tend to be more resistant to radiation. Epithelial cells do divide quickly and are reasonably sensitive, but the rapid, ongoing proliferation and the particular vulnerability of lymphocytes typically make them the most radiosensitive among these options.

Radiosensitivity is highest in cells that are actively dividing and not highly differentiated. This idea comes from the Bergonie and Tribondeau principle, which says that undifferentiated, proliferating cells have the greatest sensitivity to radiation and also the most potential to undergo mitotic arrest or apoptosis after DNA damage.

Lymphocytes fit this pattern perfectly. They are small, relatively undifferentiated white blood cells that circulate and divide rapidly in response to immune needs. Because they have a high rate of division and a limited ability to repair radiation-induced DNA damage before triggering cell death, they are extremely vulnerable to ionizing radiation. This is why lymphocytes are among the most radiosensitive cells in the body, and why radiation exposure can quickly cause a drop in lymphocyte numbers.

In contrast, nerve cells and muscle cells are mature and largely non-dividing, so they tend to be more resistant to radiation. Epithelial cells do divide quickly and are reasonably sensitive, but the rapid, ongoing proliferation and the particular vulnerability of lymphocytes typically make them the most radiosensitive among these options.