L.O  To understand how drugs work and how they are used by people.

A drug is a chemical substance that alters the working of the human body, this can come in the form of medication which alters the body in a positive way, or a recreational drug which will alter the body in a negative way
there are many different types of drugs

Type of drugEffect on body Example
 PainkillerIt blocks nervous impulses sent from the brain to stop pain being feltparacetamol
Performance enhancerHelps you perform better in sport by improving your muscle strengthAnabolic steroids
Depressant Slows down brain activityalcohol
StimulantActivates nervous impulses and increases brain activityCaffeine
Hallucinogenic  Alters you brain activity and makes you things that aren’t really thereLSD

Stimulants and depressants work on the chemical messengers known as the neurotransmitters, which travel between the neurons in the space called synapses.

By altering the neurotransmitters it affects how fast the impulse can travel around the body

Stimulants will increase the amount of neurotransmitters present where as depressants stop neurotransmitters from binding to the next neurone.


Classification of drugs

There are certain drugs which are legal and other drugs which are illegal. Most drugs used for medication purposes are legal but have to be prescribed from the doctor to prevent misuse.

Illegal drugs are classed from A to C. Class A drugs are the most dangerous and come with the highest penalty in the face of the law.

Before drugs can be releases on the maket they have to be tested to ensure there are no side effects and to make sure that they work.
There are three stages of testing

First they are tested in lab and tests are completed on a computer to ensure they can move onto the next stage

The next stage of testing is moving onto animals. They test on animals to ensure that there are no side effects and to ensure the drug actually works on a small scale

The final stage is testing on human volunteers. This stage is usually called clinical trials. They initially test on healthy volunteers then move on to those affected by the disease


Clinical trials

In clinical trials the tests are usually carried out in two groups. The first group is given the new drug and the second group is either given the old drug or a placebo. The placebo is a something that looks like a drug but is not. They are split into two groups to ensure that they can compare the results

Sometimes these trials are carried out in different ways.
Blind trials – these are trials where the volunteers do not know whether they are receiving the drug or not.
Double bind trials – these trials are when both the volunteers and the scientist do not know who is receiving the drug or the placebo



Antibiotics are a from of drug which work by slowing down the growth of bacteria

A scientist called alexander Fleming who accidently discovered it when he left bacteria in a petri dish first discovered antibiotics in 1928.

There have been many different antibiotics been developed since as many bacteria have developed a resistance towards a certain bacteria



Cigarettes have a substance called tobacco, which is very harmful to our health. Smoking can cause many different diseases due to the substances it contains. It contains a substance called nicotine which makes cigarettes very addictive.

It also contains carbon monoxide which combines with heamoglobin and prevents oxygen entering red blood cells, this places extra pressure on the heart to pump more blood around the body which can cause heart attacks and stroke

It also contains tar which can cause many different kinds of cancer



Alcohol is also a drug as it alters with the function of the body. However alcohol is deemed to be socially acceptable in regulated amount. Alcohol is a depressant as it slows down and stops signals in the brain and neurones.

The liver is a key organ is removing alcohol from the bloodstream, consuming too much alcohol can have several short term effect such as:
• A lack of judgement
• Loss of balance
• Slurred speech
• Blurred vision

There are also many long term effects such as damage to the liver and the brain. Consuming too much alcohol for long periods of time can lead to liver damage and thus preventing alcohol from being removed from the blood stream



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