Cause more neurotransmitter molecules to diffuse across the synapse
Depressants
Stop the next neurone sending nerve impulses - they bind to the receptor molecules it needs to respond to the neurotransmitter molecules
Cigarettes
Contain nicotine (addictive, leads to heart disease)
Contain tar (coats lungs, contains carcinogens that cause cancer)
Contain carbon monoxide (poisonous gas that binds to red blood cells)
Smoking and Parkinson's disease
Recent studies suggest a correlation between smoking and reduced risk of Parkinson's disease, but doctors do not advise smoking due to the much greater risks of smoking
Alcohol
Ethanol, a depressant that slows down signals in the nerves and brain
There are legal limits to the level of alcohol that drivers and pilots can have in the body
Short-term effects of alcohol
Sleepiness, impaired judgment, balance and muscle control, blurred vision, slurred speech, increased blood flow to skin
Long-term effects of alcohol
Damage to liver and brain
How the liver removes alcohol
Has enzymes that break down alcohol, but the products are toxic and damage the liver, leading to cirrhosis
