Which statement about radiosensitivity is true?

Which statement about radiosensitivity is true?

• A. Actively dividing cells that are less differentiated tend to show higher radiosensitivity
• B. Nerve tissue is the most radiosensitive
• C. Muscle tissue is highly radiosensitive
• D. Bone tissue has no radiosensitivity

Answer: (A)

Radiosensitivity is greatest in cells that are actively dividing, less differentiated, and have a high capacity to reproduce. This means that immature, proliferating cells spend more time in vulnerable phases of the cell cycle and have less time to repair DNA damage caused by radiation, so they succumb more readily. That’s why the statement about actively dividing, less-differentiated cells being more radiosensitive is true. Tissues such as bone marrow, the intestinal lining, and germ cells, which renew themselves rapidly, show high sensitivity. In contrast, nerve tissue is relatively radioresistant because neurons are largely non-dividing, and muscle tissue also tends to be resistant due to low turnover. The idea that bone tissue has no radiosensitivity isn’t correct, since bone marrow inside bones is quite radiosensitive, even if the mineralized bone matrix itself is less so.

Radiosensitivity is greatest in cells that are actively dividing, less differentiated, and have a high capacity to reproduce. This means that immature, proliferating cells spend more time in vulnerable phases of the cell cycle and have less time to repair DNA damage caused by radiation, so they succumb more readily. That’s why the statement about actively dividing, less-differentiated cells being more radiosensitive is true. Tissues such as bone marrow, the intestinal lining, and germ cells, which renew themselves rapidly, show high sensitivity. In contrast, nerve tissue is relatively radioresistant because neurons are largely non-dividing, and muscle tissue also tends to be resistant due to low turnover. The idea that bone tissue has no radiosensitivity isn’t correct, since bone marrow inside bones is quite radiosensitive, even if the mineralized bone matrix itself is less so.