Final answer:
Nauseous describes the feeling of queasiness or the urge to vomit. It is associated with various causes like hormonal changes during pregnancy, motion sickness, and decreased intestinal activity. The actual act of vomiting is triggered by the area postrema in the brain.
Step-by-step explanation:
The word nauseous is often used to describe the feeling of being about to throw up, or to vomit, though it does not mean vomiting in itself. Nausea is the sensation of queasiness that often leads to vomiting, but it is possible to feel nauseated without actually throwing up. It is a symptom that can be caused by many factors, including increased sensitivity to odors, hormonal changes, such as those experienced during pregnancy, decreased intestinal peristalsis, and conditions like motion sickness. The area postrema in the brain is responsible for inducing the act of vomiting when it detects toxins. Nausea and vomiting are also common symptoms of motion sickness due to the conflicting sensory information received by the brain.