Functions of RBC : transport around the body
One of the key functions of blood is transport. Blood
vessels are like networks of roads where deliveries and waste removal take
place. Oxygen, nutrients and hormones are delivered around the body in the
blood and carbon dioxide and other waste products are removed.
The heart is constantly pumping blood so it is always moving around the body.
Transporting oxygen is a vital role of the red blood
cells.
When we breathe in, the millions of air sacs in the
lungs fill with fresh oxygenated air. The oxygen then moves into the blood by
passing first through the very thin walls of the air sacs and then into the
capillaries, which are tiny blood vessels in a network within the lungs.
Red blood cells squeeze through
narrow capillaries in single file. Haemoglobin molecules inside red blood cells
pick up and carry the oxygen. These oxygen-rich cells travel in the blood
vessels from the lungs to the left side of the heart. The blood is then pumped
around the body.
Red blood cells are adapted for the transport of
oxygen. They are small and flexible so they can fit through narrow vessels,
have a bi-concave shape which maximises their surface area to absorb oxygen,
have a thin membrane so gases easily diffuse through, and contain haemoglobin
which binds to oxygen.
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