Why are cells important Because 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 in the body. There are more than 50,000 billion cells in your body. The shape and appearance of a cell depends on what type of job it has to do.
Nerve are long and thread like and can carry message 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 shape less so they can squeeze between other cell and attack invaders such as bacteria. Other cells control the production of essential substances called proteins.