Which cell type is drastically depleted by relatively small radiation exposure (50–70 rem)?

Which cell type is drastically depleted by relatively small radiation exposure (50–70 rem)?

• A. neurons
• B. mature spermatozoa
• C. spermatogonia
• D. muscle cells

Answer: (C)

Rapidly dividing, undifferentiated cells are the most radiosensitive. Spermatogonia, the germinal stem cells in the testes, continually proliferate to support spermatogenesis, so they fit this profile. A dose in the 50–70 rem range can drastically deplete these dividing cells, leading to a sharp decline in sperm production. In contrast, mature spermatozoa are mostly non-dividing and more differentiated, so they’re less susceptible to such doses. Neurons and muscle cells are also largely non-dividing and relatively resistant. Thus, spermatogonia are the cell type most drastically depleted by this level of radiation.

Rapidly dividing, undifferentiated cells are the most radiosensitive. Spermatogonia, the germinal stem cells in the testes, continually proliferate to support spermatogenesis, so they fit this profile. A dose in the 50–70 rem range can drastically deplete these dividing cells, leading to a sharp decline in sperm production. In contrast, mature spermatozoa are mostly non-dividing and more differentiated, so they’re less susceptible to such doses. Neurons and muscle cells are also largely non-dividing and relatively resistant. Thus, spermatogonia are the cell type most drastically depleted by this level of radiation.