Which organ system is NOT significantly affected by acute radiation syndrome?

The cognitive system is not significantly affected by acute radiation syndrome (ARS) in the same way that other systems are. Acute radiation syndrome primarily impacts rapidly dividing cells, which include those found in the hematopoietic system and gastrointestinal system. These systems are highly sensitive to radiation, leading to clinical manifestations such as bone marrow suppression and gastrointestinal distress.

While radiation can have effects on the brain and central nervous system, these are typically seen at much higher doses of radiation and are not a direct result of ARS, which primarily affects the cellular and organ systems mentioned. The cognitive system, referring to aspects such as memory and processing, does not experience the acute disturbances that characterize ARS in the same manner as the hematopoietic and gastrointestinal systems, making it the most appropriate choice in this context.