Cells

Cells

Apart from water the rest of the body is built from a huge number of complicated chemicals. These chemicals, together with water, are assembled into tiny building blocks called cells. Each cell is self-contained and has a particular function of the body. There are more than 50,000 billion cells in our body. The shape and appearance of a cell depends on what type of job it has to do. Nerve cells are long and thread – like and can carry messages around the body along the nervous system. Red blood cells are so tiny that they can only be seen under a microscope and are like flattened discs.

The sole function of the blood cell is to combine with oxygen in the lungs and to exchange the oxygen for carbon dioxide in the tissues. White blood cells are shapeless so they can squeeze between other cells and attack invaders such as bacteria. Other cells control the production of essential substances called proteins.