TYPES OF DRUGS

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TYPES OF DRUGS
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How do drugs affect the body?

• Nerves (neurones) carry information for the
  nervous system.
• There is a gap between two nerves called a
  synapse.
• Information crosses these gaps as impulses.
• Drugs affect the speed at which these impulses
  cross the gaps.

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How a synapse works
When one impulse reaches the end of a nerve
(neurone) a chemical is produced.
Impulse moves this way
The chemical moves across the gap and when it
gets to the next neurone it starts another impulse
Chemical moves across the gap
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How do drugs affect the synapse?

• Caffeine, cocaine and amphetamine are stimulants
• They work by increasing the speed by which
  impulses cross the synapse.
• Faster impulses can cause faster heart rate and
  breathing.
• Using drugs like cocaine and amphetamine can lead
  to addiction.

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Sedatives

• Sedatives are drugs which slow down the speed of
  the impulses as they cross the synapse
• Barbiturates and alcohol are sedatives
• These increase reaction times (it takes a longer
  time to do something)

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Analgesics

• Some drugs are given to relieve pain.
• These are called analgesics
• They include paracetamol, ibuprofen heroin and
  morphine.
• These work by blocking the impulses at the
  synapses in parts of the brain that deal with pain

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Taking too much

• Paracetamol is a mild pain killer and it is a
  safe drug if the correct dose is taken.
• If more is taken it is called an overdose and can
  damage the liver.
• Morphine and heroin are very strong pain killers.
• People who take them for a long time can become
  addicted.

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Solvents

• Chemicals in glues, aerosols, spray paint and
  lighters are called solvents.
• These are very dangerous.
• Solvents are breathed in and they enter the
  lungs. They then get into the blood stream and
  reach the brain.
• They slow down breathing and heart rate.
• Some people die because solvents cause heart
  failure.
• Solvents also cause damage to the nerves, brain
  damage and memory loss.

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Now try these exercises

• Exercise 7 - Matching
• Exercise 8 - Cloze