Gamma radiation makes people nauseous primarily because it damages rapidly dividing cells in the body, especially those lining the gastrointestinal (GI) tract, and disrupts normal cellular functions, triggering a cascade of biological responses that lead to nausea and vomiting. When the body is exposed to a significant dose of gamma radiation, it causes acute radiation syndrome, which often begins with symptoms such as loss of appetite, nausea, and vomiting within hours of exposure.
Here’s a detailed explanation of why this happens:
Gamma radiation is a form of ionizing radiation, meaning it has enough energy to remove tightly bound electrons from atoms, creating ions. This ionization process damages cellular components, particularly DNA, proteins, and cell membranes. The most vulnerable cells are those that divide rapidly, such as the progenitor cells in the bone marrow and the epithelial cells lining the stomach and intestines. These cells are crucial for maintaining the integrity and function of the GI tract.
When gamma radiation damages these GI tract cells, it impairs their ability to regenerate and maintain the mucosal lining. This damage leads to inflammation and disruption of the normal barrier function of the stomach and intestines. The body responds to this injury by activating the nervous system pathways that control nausea and vomiting. Specifically, the radiation-induced damage stimulates the chemoreceptor trigger zone (CTZ) in the brainstem and the vagus nerve, which transmits signals from the damaged GI tract to the brain, triggering the sensation of nausea and the reflex to vomit.
Additionally, gamma radiation causes the release of reactive oxygen species (ROS) and other free radicals, which further damage cells and tissues. This oxidative stress exacerbates inflammation and cellular injury, intensifying the symptoms. The damage to the GI tract also leads to the release of inflammatory cytokines and other signaling molecules that affect the central nervous system, contributing to nausea.
The severity of nausea depends on the radiation dose. At doses between about 1 to 10 Gray (Gy), nausea and vomiting are common early symptoms. Higher doses cause more extensive damage, leading to more severe symptoms and systemic effects such as fatigue, diarrhea, and immune suppression due to bone marrow damage.
In summary, gamma radiation induces nausea because it damages the rapidly dividing cells of the gastrointestinal lining, causing inflammation and disruption that activate neural pathways responsible for nausea and vomiting. The biochemical cascade involving oxidative stress and inflammatory signals further amplifies these symptoms. This early response is part of the body’s acute radiation syndrome, reflecting the systemic impact of ionizing radiation on sensitive tissues.
