Final answer:
The chemoreceptor trigger zone is activated by ethanol once it's absorbed into the bloodstream, leading to metabolic changes that are detected by chemoreceptors, potentially inducing vomiting.
Step-by-step explanation:
The chemoreceptor trigger zone is activated by ethanol when ethanol is absorbed into the bloodstream after the consumption of alcoholic beverages. Once in the bloodstream, ethanol can trigger increased metabolic byproducts, such as carbon dioxide, hydrogen ions, and lactic acid, while causing a fall in oxygen levels. These changes are detected by chemoreceptors that are innervated by the glossopharyngeal and vagus nerves. The activation of the chemoreceptor trigger zone can lead to the inducing of vomiting as a protective mechanism to prevent further absorption of the toxic substance.