1. Blood
• Plasma
• Platelets
• White Blood Cells
• Red Blood Cells

2. Plasma
• Transports dissolved substances:
Hormones
Fibrinogen, a
protein which helps
blood to cot.
Food (glucose
and aminoacids)
Waste
substances,
urea

3. Red Blood Cells
• This blood cells are red because of a red pigment called
Haemoglobin.
• As this cells pass through the lungs, oxygen diffuses into the
cell.
• The oxygen and haemoglobin form a new chemical called
oxyhaemoglobin, which is carried around the body to organs
and tissues.
• When the red blood cells reach cells in the body that have
little oxygen, the oxyhaemoglobin splits back into O2 and
Haemoglobin.

4. Red Blood Cells Shape
• Red blood cells have a biconcave shape with a large surface
area.
• The large surface area allows more oxygen to diffuse in and
out of cells.
• Red Blood cells do not have a nucleus, and that allows more
room for haemoglobin.

5. Role of White Blood Cells
Phagocyte
• White Blood Cells Body´s defense
system
Lymphocyte
• Phagocytes can leave the blood channel and enter any tissue.
• These blood cells swarm any bacteria they find, enclose it
inside them and Digest it. This process is called Phagocytosis.

6. Role of White Blood Cells
• Lymphocytes are made in glands called Lymph Nodes.
• When pathogens enter the body, white blood cells recognize
the foreign proteins, called antigens, on the outside of the
pathogens.
• White blood cells produce proteins called antibodies, which
destroy the pathogens.
• This antibodies can also destroy the toxins produced by
germs. There is a different kind of antibody for every germ.
• This actions are known as immune responses. The protection
the immune responses give you is known as natural
immunity.
• Sometimes the lymph nodes swell up during an immune
response, and it is possible to feel the nodes in your neck,

7. Platelets
• Platelets are small fragments of red blood cells, which ensure
that your blood clots when you cut yourself.
• A clot protects against microbes entering your body through
the wound.
• A clot is formed when the platelets clump together.
• This triggers off a chemical reaction, turning the soluble
protein fibrinogen into fibrin, which doesn't dissolve in blood
• These fibrin fibres create a web, which traps the blood
underneath and leaves a clot or scab on the surface.