How does alcohol make you drunk? - Judy Grisel
-
0:07 - 0:12Ethanol: this molecule, made of little
more than a few carbon atoms, -
0:12 - 0:15is responsible for drunkenness.
-
0:15 - 0:18Often simply referred to as alcohol,
-
0:18 - 0:21ethanol is the active ingredient
in alcoholic beverages. -
0:21 - 0:24Its simplicity helps it
sneak across membranes -
0:24 - 0:26and nestle into a many different nooks,
-
0:26 - 0:31producing a wide range of effects
compared to other, clunkier molecules. -
0:31 - 0:34So how exactly does it cause drunkenness,
-
0:34 - 0:39and why does it have dramatically
different effects on different people? -
0:39 - 0:40To answer these questions,
-
0:40 - 0:44we’ll need to follow alcohol
on its journey through the body. -
0:44 - 0:47Alcohol lands in the stomach
and is absorbed into the blood -
0:47 - 0:51through the digestive tract,
especially the small intestine. -
0:51 - 0:54The contents of the stomach
impact alcohol’s ability -
0:54 - 0:58to get into the blood because
after eating, the pyloric sphincter, -
0:58 - 1:01which separates the stomach
from the small intestine, closes. -
1:01 - 1:04So the level of alcohol that reaches
the blood after a big meal -
1:04 - 1:09might only be a quarter that
from the same drink on an empty stomach. -
1:09 - 1:12From the blood,
alcohol goes to the organs, -
1:12 - 1:14especially those that get
the most blood flow: -
1:14 - 1:17the liver and the brain.
-
1:17 - 1:20It hits the liver first,
and enzymes in the liver -
1:20 - 1:23break down the alcohol molecule
in two steps. -
1:23 - 1:29First, an enzyme called ADH turns alcohol
into acetaldehyde, which is toxic. -
1:29 - 1:36Then, an enzyme called ALDH converts the
toxic acetaldehyde to non-toxic acetate. -
1:36 - 1:40As the blood circulates, the liver
eliminates alcohol continuously— -
1:40 - 1:44but this first pass of elimination
determines how much alcohol -
1:44 - 1:47reaches the brain and other organs.
-
1:47 - 1:51Brain sensitivity is responsible
for the emotional, cognitive, -
1:51 - 1:57and behavioral effects of alcohol—
otherwise known as drunkenness. -
1:57 - 2:01Alcohol turns up the brain’s
primary brake, the neurotransmitter GABA, -
2:01 - 2:06and turns down its primary gas,
the neurotransmitter glutamate. -
2:06 - 2:09This makes neurons
much less communicative, -
2:09 - 2:13and users feel relaxed at moderate doses,
fall asleep at higher doses, -
2:13 - 2:19and can impede the brain activity
necessary for survival at toxic doses. -
2:19 - 2:22Alcohol also stimulates
a small group of neurons -
2:22 - 2:26that extends from the midbrain
to the nucleus accumbens, -
2:26 - 2:28a region important for motivation.
-
2:28 - 2:30Like all addictive drugs,
-
2:30 - 2:33it prompts a squirt of dopamine
in the nucleus accumbens -
2:33 - 2:36which gives users a surge of pleasure.
-
2:36 - 2:41Alcohol also causes some neurons
to synthesize and release endorphins. -
2:41 - 2:45Endorphins help us to calm down
in response to stress or danger. -
2:45 - 2:47Elevated levels of endorphins
contribute to the euphoria -
2:47 - 2:51and relaxation associated
with alcohol consumption. -
2:51 - 2:52Finally,
-
2:52 - 2:56as the liver’s breakdown of alcohol
outpaces the brain’s absorption, -
2:56 - 2:58drunkenness fades away.
-
2:58 - 3:01Individual differences
at any point in this journey -
3:01 - 3:04can cause people
to act more or less drunk. -
3:04 - 3:08For example, a man and a woman who weigh
the same and drink the same amount -
3:08 - 3:13during an identical meal will still have
different blood alcohol concentrations, -
3:13 - 3:15or BACs.
-
3:15 - 3:18This is because women
tend to have less blood— -
3:18 - 3:20women generally have
a higher percentage of fat, -
3:20 - 3:22which requires less blood than muscle.
-
3:22 - 3:26A smaller blood volume,
carrying the same amount of alcohol, -
3:26 - 3:29means the concentration
will be higher for women. -
3:29 - 3:35Genetic differences in the liver’s alcohol
processing enzymes also influence BAC. -
3:35 - 3:38And regular drinking can
increase production of these enzymes, -
3:38 - 3:40contributing to tolerance.
-
3:40 - 3:44On the other hand, those who drink
excessively for a long time -
3:44 - 3:48may develop liver damage,
which has the opposite effect. -
3:48 - 3:52Meanwhile, genetic differences
in dopamine, GABA, -
3:52 - 3:55and endorphin transmission
may contribute to risk -
3:55 - 3:58for developing an alcohol use disorder.
-
3:58 - 4:01Those with naturally low endorphin
or dopamine levels may self-medicate -
4:01 - 4:03through drinking.
-
4:03 - 4:05Some people have a higher risk
for excessive drinking -
4:05 - 4:09due to a sensitive endorphin response
that increases the pleasurable effects -
4:09 - 4:10of alcohol.
-
4:10 - 4:13Others have a variation
in GABA transmission -
4:13 - 4:17that makes them especially sensitive
to the sedative effects of alcohol, -
4:17 - 4:21which decreases their risk of developing
disordered drinking. -
4:21 - 4:26Meanwhile, the brain adapts to chronic
alcohol consumption by reducing GABA, -
4:26 - 4:30dopamine, and endorphin transmission,
and enhancing glutamate activity. -
4:30 - 4:34This means regular drinkers tend
to be anxious, have trouble sleeping, -
4:34 - 4:38and experience less pleasure.
-
4:38 - 4:41These structural and functional changes
can lead to disordered use -
4:41 - 4:45when drinking feels normal,
but not drinking is uncomfortable, -
4:45 - 4:48establishing a vicious cycle.
-
4:48 - 4:53So both genetics and previous experience
impact how a person experiences alcohol— -
4:53 - 4:56which means that some people
are more prone -
4:56 - 4:58to certain patterns
of drinking than others, -
4:58 - 5:03and a history of consumption leads
to neural and behavioral changes.
- Title:
- How does alcohol make you drunk? - Judy Grisel
- Speaker:
- Judy Grisel
- Description:
-
View full lesson: https://ed.ted.com/lessons/how-does-alcohol-make-you-drunk-judy-grisel
Ethanol: this molecule, made of little more than a few carbon atoms, is responsible for drunkenness. Often simply referred to as alcohol, ethanol is the active ingredient in alcoholic beverages. So how exactly does it cause drunkenness, and why does it have dramatically different effects on different people? Judy Grisel explores alcohol's journey through the body.
Lesson by Judy Grisel, directed by Anton Bogaty.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:04
Elise Haadsma approved English subtitles for How does alcohol make you drunk? | ||
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