by Esther Inglis-Arkell
There's a whole lot of things that people stuff in their faces. Some of them keep those people alive. Some of them taste good to those people. Some of them help those people win pie-eating contests. Alcohol does none of those things. Why do people keep putting it in their bodies? And what does it do once it gets there?
There are all kinds of alcohol molecules, but the one that people most often pour down their throat is ethanol. This is a molecule that, in technical chemistry terms, looks like a doggie. Two carbon atoms are stuck together to support an oxygen head. Six hydrogen atoms spread out over the molecule to give each of the carbon atoms two feet, the oxygen atom a nose, and the rear carbon atom a tail. Ethanol is compact and water soluble, so like a doggie, it gets into all sorts of places that it's not supposed to.
Alcohol heads for the digestive system and because it's water soluble, gets into the water in the bloodstream. Because ethanol, to a certain extent, can move through lipids, it can pass through cell membranes. Between that and the bloodstream, it can go pretty much anywhere. It spreads through the muscles, and is exuded –unmetabolized and whole – through the skin. It gets into the heart. It even takes a walk through the brain, and this is the secret of its powers.
Once there, alcohol acts on a certain part of the brain, the nucleus accumbens. This area is a midpoint between the reward center of a brain and the parts that make associations and memories. Alcohol causes a bunch of dopamine to be released in the nucleus accumbens, hot-wiring the system. It makes people feel good.
It also makes people feel confident and talkative, although it's considered a depressant. It depresses brain function. Alcohol isn't confined to the reward center of the brain. Instead it wanders all around the brain. When nerves communicate with each other, one gives off a certain chemical. The other picks up the chemical with its receptors, and once it picks up enough, it gets activated itself. Alcohol binds to many kinds of receptors. It holds on to glutamate receptors, but doesn't activate them. Glutamate is what excites neurons, so if many glutamate receptors are blocked, a certain stimulation that would activate the brain gets a slower, or depressed response. Alcohol also binds to GABA (gamma aminobutyric acid) receptors. These it does activate, but GABA receptors slow the brain down. This helps a drunk person feel calm and sleepy, and it further depresses brain activity. This is also why caffeine feels like it ‘sobers' a person up, but doesn't. Caffeine may help people not feel sleepy, but it can't unblock those receptors.
Everyone knows that too much alcohol at once can kill people, but how? As said before, alcohol depresses the nerves, and the nerves affect pretty much every area of the body. Enough alcohol makes people sleep and suppresses the gag reflex, so people who are passed out choke on their own vomit. Most worrying, always, is alcohol stomping around in the brain. Even at its most primitive, the brain controls things like breathing and heart rate. However, enough alcohol can shut down those parts of the brain just like any other part. People pass out and their brains simply forget to breathe.
Alcohol is broken down in the liver, at some cost to the liver itself. Alcohol doesn't destroy the liver, but products that the liver breaks the alcohol into do cause damage. Meanwhile, any alcohol that isn't metabolized wanders around the body, coming out in urine from the kidneys, seeping from the skin, or being breathed out by the lungs.
Not that alcohol doesn't have its good side. Depending on what articles are to be believed, a glass of wine per day can either not do any harm, can prevent heart attacks, or can make someone functionally immortal. And it is kind of nice to know that sometimes, relaxation and cheer can literally be bottled. All that's needed is to take care how much alcohol is let into a person's brain.