Human body
-
Body cells need oxygen and food to survive
- Within the cells of
your body a process called respiration releases energy from your food so that the cells can work.
- Food and oxygen are
needed for respiration
- Water and carbon
dioxide are wastes
- The word equation
for respiration is:
Food + oxygen  energy + carbon dioxide + water
- Your digestive
system provided the food for respiration to take place
- Your respiratory
system collects oxygen for respiration and gets rid of the waste carbon
dioxide.
- Your circulatory
system carries food, oxygen and carbon dioxide for respiration
The digestive system:
- Digestion is the
process of breaking down food into a useable form that is then taken into
the body and used for a variety of purposes.
- In digestion chemicals called enzymes help to break the food down into soluble particles which
can pass through the wall of the small intestine into the blood.
- The wall of the small intestine is very thin to allow
dissolved food to pass through into the blood
- The wall of the small intestine is folded to give it a
very large surface area for food particles to pass through
Tooth decay
 ;;
- To reduce tooth decay:
- Brush your teeth twice a day
- Reduce your eating of sweets and fizzy drinks
- Eat more fruit and uncooked vegetables.
The Heart
- Your heart is a muscular pump:
- It lies in the centre of your chest between your lungs
- It is used to send blood all round your body.;
- Your pulse lets you measure how fast your heart beats,
- you can find your pulse in your wrist;and neck.;
- Your blood carries food;and oxygen;to all
parts of your body
- Your heart muscles need blood too – this is provided
through the coronary artery
- Your heart is made up of four chambers:
- the left atrium and ventricle
- the right atrium and ventricle
- the blood passing through it is kept going in the right direction by valves.
- Because food, oxygen,
carbon dioxide and waste are carried in your blood – the blood must be carried
near to every living cell in your body.
- Your heart contains 4 chambers and 4 valves
- Blood leaves the heart in arteries
- Arteries carry blood away from the heart
- To carry blood under high pressure they must have
thick, elastic walls
- Blood arrives at the heart in veins
- Veins carry blood from the body to the heart
- There is less pressure so they can have thinner, less
elastic walls.
- To prevent the blood flowing back between the
heartbeats they have valves
The Blood ;
; 
- Blood is made up of plasma, red blood cells, white cells and
platelets
- Plasma is the liquid part of the blood
- It carries dissolved food and carbon dioxide
- Red blood cells carry oxygen
- White cells fight disease
- Platelets are involved in blood clotting after a cut.
The Respiratory System;;;;;;;;
- Breathing;is when
air is drawn in and out of your lungs.;
- The air passes down through your windpipe and
into the two bronchi.;
- Rings of cartilage;stop the windpipe from
“kinking” when your head is moved.
- The bronchi divide up into many tiny
bronchioles
- Each bronchiole ends in an alveolus (air sac)
- Breathing in is caused by your ribs moving up and out and your
diaphragm;moving down. ;;
- Breathing out is caused by your ribs moving down and in and
your diaphragm;moving up. ;
- Your body needs oxygen to get energy from
your food.
- Air entering your lungs it is
made up of 20% oxygen, 80% nitrogen with just a trace of carbon dioxide (379
parts per million).
- In your lungs the
oxygen passes into your blood and waste carbon dioxide passes out of your blood
into the air.
- When you breathe out the
air is made up of only 16% oxygen and 4% carbon dioxide, the nitrogen is not
used by your body and is unchanged.;
Air |
Oxygen |
Carbon dioxide |
Nitrogen |
Breathed
in |
20% |
trace |
80% |
Breathed
out |
16% |
4% |
80% |
The Excretory System
- Your kidneys help to keep the water level
of your blood correct.
- You gain water by eating and drinking, you
lose water by sweating, breathing;and in your urine
- Your kidneys produce the urine;by
taking water out of your blood.;
- The urine is stored in your bladder;until
it is passed out through the urethra
;
Skeletal System
- Your skeleton is needed for:
- Support for your inside bits
- Movement – along with muscles the
skeleton lets you move
- Protection – your brain, lungs and
heart are protected by bones
;
; - The muscles bring about movement by
putting a force on the bones
- The diagram shows the muscles and
bones of the arm
- If the biceps puts a force on the
arm it will bend
- If the triceps puts a force on the
arm it will straighten
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