1Into the blood
The alcohol in drinks is ethanol. It is absorbed through the walls of the stomach and small intestine into the blood within minutes, and travels to every organ, including the brain.
ethanol
Lesson 16.3 notes
Alcohol
Where alcohol goes in the body, what it does in the short and long term, working out units, and the law.
2The liver
Alcohol is poisonous, so the liver breaks it down. It can only break down about one unit an hour, so it takes many hours to clear a lot of alcohol from the blood.
liver
3Short-term effects
Alcohol is a depressant. It slows reactions and makes balance, speech and judgement worse. Drinking a lot at once can cause alcohol poisoning, which can be life-threatening.
depressantalcohol poisoning
4Long-term effects
Heavy drinking over many years can scar the liver (cirrhosis), raise blood pressure, damage the heart and brain, cause several cancers, and lead to addiction.
cirrhosis
5What's in a drink
A label shows a drink's strength as % ABV: the percentage of its volume that is alcohol. A 500 ml drink at 5% holds 25 ml of pure alcohol. One unit is 10 ml.
ABVunit
6Working out units
units = volume (ml) × strength (%) ÷ 1000. A 500 ml drink at 5%: 500 × 5 ÷ 1000 = 2.5 units. A 750 ml bottle at 12% holds 9 units.
units
7The law and advice
It is illegal to sell alcohol to under-18s, or to drive with too much alcohol in the blood. For under-18s, no alcohol is healthiest; in pregnancy, the advice is none at all.
illegal
Explore: Units lab
Change the size and the strength of a drink to see how much pure alcohol it holds, and work out the units.
Common mistake: A unit isn't one drink
One unit is 10 ml of pure alcohol. A single drink can hold several units: a large glass of wine has about 3. Counting drinks instead of units can badly underestimate how much alcohol someone has had.
Remember
- Alcohol (ethanol) is absorbed into the blood from the stomach and small intestine and reaches every organ. The liver breaks it down.
- Alcohol is a depressant: it slows reactions and harms judgement and balance. Heavy drinking over years damages the liver, heart and brain.
- units = volume (ml) × strength (%) ÷ 1000. It is illegal to sell alcohol to under-18s, and no alcohol is healthiest for them.
Going further at GCSE