1.1 Symptoms are us usually caused by the cell
damage caused by the microorganism or by
the toxins produced by the microorganism.
1.2 The microorganisms
reproduce quickly inside
the human body.
1.2.1 Bacteria reproduce by creating copies of
themselves and need a source of nutrients and
warm nd moist conditions to do this.
1.2.2 Viruses need other cells to reproduce and
use parts of other cells to make copies of
1.2.3 Most microorganism can reproduce very
2 The Immune System
3.1 Involves injecting dead or inactive microorganisms. They
still carry the antigens which still alows the body to try and
attack hem but they are harmless. The body then creates
memory cell that will recognise the microorganism if it
ever eters the body again. And the body will be able to
attackthe microorganisms quickly, without the person even
recieving any symptoms.
3.2 They can prevent epidemics.
3.3 However, they arent completely safe as different people may have
different side effects to the vaccination. As well as genetic differences in
people which could cause people to react differntly to the drug. The
microorgnisms in the vacination could also be active and alive when they
should be dead aor inative, and the person may actually recieve the
4.1 They are chemicals created th inhibit the growth of
microorganisms or kill them, without damaging the bodies
4.1.1 They can kill bacteria but not viruses such as flu and colds.
4.2 After time many microorganisms can develop
muations in their DNA which cause them to be
immune to the antimicrobial.
5 Drug Trials
5.1 When a new drug is created, it is first tested on human cells that are grown in thelaboratory, to see the
drugs actual affect on real human cells and to see if they appear to be safe and are actually working.
The drug then has to be tested on two species of live mammals. If any poyential harmful substances are
found in the drug after testing it on the animals, they can be weeded out of the drug before it is tested
on human volunteers. If the drug causes serious problems to the animals, the drug probably wont go
any further, but if its fine, it will then go on to be tested on humans.
5.2 Three main types of trial- Blind, Double Blind and
5.3 Placebos are sometimes used to compare people who have the drug and people
who don't to see if the effects are correct and aren't compromised. But placebos
often aren't used with ill people because its unethical.
6 The Circulatory System
6.1 The heart and blood vessels supply
blood around the body
220.127.116.11 They carry blood from the heart to the body cells.
The blood comes out of the heart at high
pressure, so the artery walls have to be thick and
18.104.22.168 Veins carry blood back to the heart. The blood is at lower
pressure so the walls dont have to be that thick. They have a
large lumen to allow easy blood flowand they have valves to
ensure the blood flows in the correct way.
22.214.171.124 These are branches off arteries that are very small. They are very close to the cells
to allow the exchanges of substances to the cells. They also have permeable walls
to allow diffusion, in and out of them. They sup[ply the cells with nutrients and
oxygen and take away the carbon dioxide. Their walls are only one cell thick.
6.2 The blood vessels carry oxygen and nutrients to the body cells
and carry waste such as carbon dioxide away from the cells. The
heart keeps the blood pumping through the vessels and the heart
is a double pump. The right side of the heart pumps
de-oxygenated blood to the lungs to collect oxygen and to
remove carbon dioxide. Whereas the left hand side pumps
oxygenated blood around the body. The heartr itrself is supplied
with blood by two coronary arteries which branch from the base of
7 Heart Rate and Blood Pressure
7.1 Heart Rate is the number of times your heart beats in a minute- BPM.
7.2 Pulse rate is the number of times an artery pulsates in one minute.
7.3 Blood Pressure is the pressure of the blood when its contract and relaxes. E.G. 135 over 85.
7.3.1 If your blood pressure is high, you are
at higher risk or heart disease which
can be fatal.
7.4 All of these measurements can be
used to decide if a person is healthy or
8 Heart Disease
8.1 it is often linked to lifestyle factors
but in some people it can be due to
8.2 It can be caused by a poor diet, smoking, stress, the
misuse of drugs or excessively drinking alcohol.
8.3 Regular exercise can reduce your risk of heart disease.
8.4 Epidemiological Studies can identify possible risk factors.
9.1 Definition: Balancing Inputs with outputs to
maintain a constant internal environment.
9.1.1 Water Content
126.96.36.199 Inputs: Drinks, Food and Respiration.
Outputs: Sweating, Breathing Faeces and
188.8.131.52 Alcohol decreases the production of
ADH whereas Ecstasy increases the
production of ADH.
9.1.2 Body Temperature
9.2 All control systems are made up of receptors,
processing centres and effectors.