2. Red cells:
Most common blood cell, making around 45% of the
blood.
Doughnut-shaped.
Do not have a nucleus.
Contain haemoglobin (which is why they’re red)
Live for approximately 120 days.
Carry oxygenated blood from lungs to cells that
need it.
3. White cells
Search for bacteria
Carry antibodies
Antibodies = our bodies’ defences against viruses
and bacteria.
Part of: our immune system.
4. Platelets
Fragments of cells
Used to help clot (coagulate) the blood.
Platelets live for an average of 10 days.
5. Plasma
Is a pale yellow colour
Is 90% water
Plasma allows other blood cells to move around.
6. It is made in the centre of our bones = in our bone
marrow.
7. There are three types of blood vessel:
Arteries
Carry blood away from the heart
(always oxygenated apart from the pulmonary
artery which goes to the lungs)
Have thick muscular walls
Have small passageways for blood
(internal lumen)
Contain blood under high pressure
8.
9. Veins
Carry blood to the heart (always de-oxygenated
apart from the pulmonary vein which goes from
the lungs to the heart)
Have thin walls
Have larger internal lumen
Contain blood under low pressure
Have valves to prevent blood flowing backwards
10.
11. Capillaries
Found in the muscles and lungs
Microscopic – one cell thick
Very low blood pressure
Where gas exchange takes place. Oxygen passes
through the capillary wall and into the tissues,
carbon dioxide passes from the tissues into the
blood
12. When an infective cell is detected, white blood
cells will send out a message to another type of
cell: t-helper cells.
This also triggers your immune system.Your body
releases millions of antibodies to fight off the
enemy cells.
The antibody cells join themselves to the bacterial
cell in an attempt to overpower it.
13. As this process continues, the number of infectious
cells will decrease and the body can stop the battle.
Another kind ofT cell, theT-suppressor cell (orT8 cell),
will send out messages to the other cells and "de-
activate" them.
Without theT-suppressor cells, the body would
continue trying to fight off a disease that no longer
exists (and eventually would end up fighting its own
cells).
14. Bruising is caused by blood vessels becoming
damaged, which causes bleeding into the skin.
15.
16. Control of body temperature
Keeping out infection
It´s a waterproof barrier
Protects delicate tissues underneath
Mends itself when damaged
