Transport - Circulatory System etc.

It's missing the structure of the kidneys but the rest should be helpful for revision.


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  • Created on: 17-04-11 11:45
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The Circulatory System
In large animals and humans a transport system is needed to circulate chemicals around the body.
Oxygen and glucose are needed for respiration by every cell which needs to get rid of waste products
such as carbon dioxide and urea.
This is the function of the blood circulation system ­ this has three components; the blood vessels, the
heart and the blood.
Double Circulation
Humans have two circulatory systems; this is double circulation.
One carries blood from the heart to the lungs and back again to exchange
oxygen and carbon dioxide with the air.
The other carries blood all around the rest of your body and back again.
Double circulation is very important in warm-blooded and active animals, such
as humans as it makes the circulatory system very efficient.
The main advantage of this is that it allows fully oxygenated blood to be sent to
different parts of the body.
The Blood Vessels
The arteries carry blood away from the heart to the organs in the body.
This is usually oxygenated blood and so it is bright red.
They stretch as the blood is forced through them and go back into their
original shape afterwards.
This can be felt as a pulse where the arteries run close to the surface; e.g.
the wrist.
The veins carry blood towards your heart.
This is usually deoxygenated blood and so it is a deep purple-red colour.
They do not have a pulse.
They often have valves to prevent the back-flow of blood as it moves from
various parts of the body back to the heart.
In the organs of the body, between the arteries and the veins; the blood
flows through a huge network of capillaries.
Capillaries are narrow with very thin walls so the substances needed by the
body cells, such as glucose and oxygen can easily pass into the cells by
Similarly the substances produced by the cells, such as carbon dioxide,
pass easily into the blood through the walls of the capillaries.
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The Structure of The Heart
Blood is pumped around the body by
a muscular heart. Blood travels away
from the heart in arteries. These
contract and pump the blood along.
This can be felt as a pulse.
Blood returns to the heart in veins.
These have thinner walls than
arteries. Blood is prevented from
flowing backwards in them by valves.
The smallest blood vessels are
called capillaries.…read more

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Oxygen diffuses out of the red blood cell.
White Blood Cells
Produce antibodies and antitoxins to fight pathogens; some can engulf and destroy pathogens directly.
The Effect of Exercise on The Body
The muscles need energy in order to contract.
Muscle fibres contain many mitochondria to supply the energy they need by aerobic respiration.
When we exercise, our muscles contract more quickly and with more force.
This requires more energy.
This requires more glucose and oxygen.…read more

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This is the amount of oxygen needed to break down the lactic acid and repay the oxygen needed by
the muscles previously.
The pulse and breathing rate remains high to repay the debt.
Kidney Failure
Kidney Dialysis
People with kidney failure can be kept alive by having dialysis treatment ­ this involves using
machines which do the job of kidneys.
1) A needle is inserted
into a blood vessel in
the patient's arm to
remove blood.…read more

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Unfortunately this means that the patient can't fight any disease that comes along so they need to
be in totally sterile conditions for some time after the operation.
The Advantages and Disadvantages of Kidney Dialysis and Transplants
Advantages Disadvantages
The patient must take drugs to suppress
their immune system which can leave
One-time treatment.
them vulnerable to other illnesses.
Patient can lead a relatively normal life.
Transplant Can be difficult to find a kidney donor.
Diet doesn't need to be controlled.
Risk of infection.…read more


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