Download Unit 13 - Drug Abuse

Topic 13 – The Use and Abuse of Drugs
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13.1 – Antibiotics, 13.2 – Effects of heroin, 13.3 Effects of alcohol,
13.4 – Effects of tobacco smoke
SUFEATIN SURHAN  BIOLOGY MSPSBS  2010
SYLLABUS CHECKLIST
Candidates should be able to:
a) Define a drug as any externally administered substance that modifies or affects chemical reactions in
the body;
b) describe the medicinal use of antibiotics for the treatment of bacterial infection;
c) describe the effects of the abuse of heroin: a powerful depressant, problems of addition, severe
withdrawal symptoms and associated problems such as crime and infection e.g. AIDS;
d) describe the effects of excessive consumption of alcohol: reduced self-control, depressant, effect on
reaction times, damage to liver and social implications;
e) describe the effects of tobacco smoke and its major toxic components (nicotine, tar and carbon
monoxide) on health: strong association with bronchitis, emphysema, lung cancer and heart disease,
and the association between smoking during pregnancy and reduced birth weight of the baby;
f)
recognize the fact that many people regard smoking as no longer socially acceptable.
Hormones are chemicals naturally present in the body which
USES OF DRUGS
affects chemical reactions. However, external chemicals can
Drugs may be used for beneficial effects:
also be used to change or affect chemical reactions in the
body. These are drugs.
a)
For treatment of diseases such as antibiotics.
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Definition of a Drug
pneumonia, syphilis and gonorrhoea, which are
An externally administered chemical substance which
modifies or affects chemical reactions in the body.
This class of drugs only treats diseases such as
specifically caused by bacteria.
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When consumed, antibiotics only kill the diseasecausing bacteria but they do not affect the normal
Drugs can be administered into the body by four ways:
body cells at all.
1.
By oral consumption.
2.
By injection.
3.
By inhalation.
preventing the synthesis of bacterial cell wall, hence,
4.
By application onto the skin.
the bacteria die by lysis due to osmotic pressure.
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One mechanism by which antibiotics kill bacteria is by
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A well known antibiotic is penicillin, which is made
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from the blue-green mould / fungus, Penicillium. In
(numbness), removes feelings of anxiety and creates
the treatment of syphilis, this is given by injection.
a sense of extreme well being (euphoria).
Other common antibiotics are tetracycline and
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Its use in medicine is highly controlled due to its
amphiciline.
highly addictive nature where it is used for the relief
The full course of the antibiotics given must be
of severe pain only.
completed in order to ensure the death of all of the
The body can become tolerant to heroin i.e. progressively
disease-causing bacteria in the body.
increased dosages of the drug is required to maintain the
If the antibiotic course is not completed, some
same feelings of well being.
bacteria may survive and evolve a defensive
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mechanism against the antibiotic, making them
The abuser may end up in a state of dependence, where
resistant to the antibiotic.
they crave the drug and cannot face life without it.
Future treatment against this resistant strain of
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This poses the danger of death from over dosage.
In the absence of the drug, they suffer from severe
bacteria with this antibiotic will no longer be
withdrawal symptoms such as diarrhea, vomiting,
effective. A different and stronger antibiotic will need
muscular pain, shaking and hallucination.
to be used.
Addiction often results in social problems as follows:
The fact that antibiotics may be successful in helping
1.
Obsession on obtaining the drug means that they are
to cure a bacterial infection when the immune system
unable to concentrate on their job, inevitably leading
can no longer cope was not often mentioned, but
to unemployment.
that such conditions may be cured more quickly with
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As a consequence, there is no money for them to
the aid of antibiotics was well known.
support their expensive habit as well as to
Disadvantages: possible allergic reactions.
support their family.
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b) For pain relief i.e. as pain killers such as paracetamol,
c)
It results in a sedative effect i.e it dulls the senses
They then tend to resort to a life of crime to
aspirin, morphine, heroin.
obtain money for regular access to the drug as
For treating emotional disorders such as depression.
well as having dysfunctional families (divorce).
2.
The sharing of unsterilized needles between several
DEFINITION OF DRUG ABUSE
users means that they are at a high risk of contracting
When a drug is taken simply for enjoyment/recreational
blood-borne diseases such as hepatitis and HIV /
AIDS.
purposes, often in large amounts and often leads to
addiction.
ALCOHOL – A depressant drug
Heroin, alcohol and nicotine are three drugs which are
A widely used and readily available (legal) drug in many
commonly abused and their effects on the body and the
societies - Generally regarded as a ‘socially acceptable’
society are listed below
drug.
HEROIN – A depressant drug
It is a depressant affecting the cerebrum and the
cerebellum resulting in the following:
Normally taken into a vein via a hypodermic needle.
It is a powerful depressant
Result of effect on cerebrum:
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It creates a feeling of well being
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Blurry vision
also from physical violence or sexual abuse, which
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Slurred speech
often accompanies alcoholism.
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Poor concentration and judgement
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When consumed in increasing quantities, it leads to
which many innocent people have been killed in road
reduced and eventually loss of self control (loss of
accidents.
inhibition) causing the person to behave in a way
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Drunk drivers are the cause of many fatal accidents in
NICOTINE – A stimulant drug
they would be ashamed of when sober.
Effects of smoking on health
Result of effect on cerebellum:
Cigarette smoke contains around 4000 harmful chemicals.
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It slows down reaction times due to the resultant
Some of them are nicotine, tar, carbon monoxide and
poor muscle coordination. This, as well as the above
irritants.
effects, increases the risk of accident when a drunk
Their effects on health are summarised below:
person drives.
Component
Nicotine
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Question:
How does alcohol enter the bloodstream?
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What is the actual effect of alcohol on neurons?
In the long term, it also leads to liver damage such as liver
Tar
cirrhosis and cancer which can eventually prove fatal.
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Why is liver affected?
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It also results in malnutrition since alcoholics tend to only
consume the non-nutritional alcoholic drinks in excess (no
balanced diet), often leading to obesity (‘Beer belly’) as
the excess alcohol molecules (high calorie value) are
Carbon
monoxide
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converted into fats and stored in the adipose tissues in
the body.
It is also highly addictive (become an alcoholic)
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Its withdrawal symptoms are less severe than that of
heroin but a person may go to great lengths to satisfy
their cravings.
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Often families suffer as a consequence (family
breakdown), not only from financial hardship, but
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Irritants
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Effect/s
A highly addictive drug.
- May cause relatively mild withdrawal
symptoms if craving for nicotine not
satisfied.
A
stimulant:
stimulate
adrenaline
production, which increases heart rate and
blood pressure.
Causes constriction of blood vessels.
Increase blood clotting, hence, increased
risk of thrombosis (blockage in a blood
vessel due to blood clot).
A dark brown sticky substance, which
enters the lungs as minute aerosol
droplets.
Stains teeth and fingers of smokers.
Forms a layer over the epithelial cells of
the walls of the alveoli, restricting gaseous
exchange.
A carcinogen (cancer causing substance)
o Prolonged exposure to it may lead to
lung cancer which may metastasize to
other parts of the body
A colourless and odourless poisonous gas.
Combines with haemoglobin in red blood
cells permanently / irreversibly forming
carboxyhaemoglobin (instead of with
oxygen).
- Greatly reduce the ability of the blood
to carry oxygen.
Damages lining of blood vessels and
increases formation of atheroma of their
walls.
Cause cells lining the bronchi and
bronchioles to increase their production of
mucus, narrowing the air passages.
Results in ‘smoker’s cough’ which provides
a temporary relief since coughing
temporarily displaces the thick mucus.
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However, prolonged coughing may damage
the walls of the alveoli causing them to
become overstretched and may lead to
emphysema.
Destroy the cilia lining the trachea,
increasing the chances of inflammation of
the bronchial walls and may lead to
bronchitis.
This is further worsen by nicotine, which constricts the
maternal arteries in the placenta. Hence, less oxygenated
blood and nutrients can reach the foetus.
Babies born to mothers who smoke during pregnancy
have been shown to be:
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Bronchitis
nutrients and oxygen).
Bronchitis is an inflammation of the bronchial tubes,
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particularly the bronchioles. This results in the production
of large quantities of thick mucus or phlegm which the
person coughs up frequently.
Emphysema
foetal stage).
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Having a greater risk of miscarriage, premature births
and stillbirths.
Passive smoking
Evidence now exists that breathing the smoke from other
be difficult to breathe out air from the alveoli and the
people’s cigarettes can be harmful (inhalation of
bronchioles. The alveoli will then become stretched to an
unfiltered second-hand smoke).
abnormal degree.
Cigarette smoke is certainly an irritant to the eyes and
Coughing will weaken the walls of the alveoli, causing
leaves a lingering smell in clothes.
them to break down, and holes appear.
Smoking is therefore increasingly becoming a socially
The surface area for gas exchange will be reduced and
unacceptable habit.
Heart diseases
Large proportions of people who die from coronary heart
disease are heavy smokers.
It is associated with the deposition of fatty material in the
lining of the coronary artery due to the increase in the
blood clotting effect of nicotine..
This reduces the flow of blood to the heart muscles and
the heart muscle is deprived of oxygen.
Pregnancy and Smoking
A pregnant woman who smokes also risks the health of
her baby.
Carbon monoxide causes less oxygen to reach the foetus
as the carbon monoxide combine with the haemoglobin in
the mother’s red blood cells to form a compound called
carboxy-haemoglobin that cannot transport oxygen.
(CO + Hb  COHb)
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Less intelligent (brain development affected in the
When phlegm accumulates in the bronchial tubes, it will
breathing efficiency is affected.
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Underweight (slow physical growth due to insufficient
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