A certain portion of the ethanol you drink passes through your stomach to your small intestine, is absorbed into your bloodstream and carried to your brain. That’s what we’re really concerned with. Research has not conclusively determined exactly how ethanol accomplishes all of its various effects in the brain, but there are some well-supported theories. The slow reactions, slurred speech and memory loss of a drunk are probably caused by ethanol attaching to glutamate receptors in your brain’s neural circuitry.