Red blood cells:
Red blood cells (erythrocytes), carry around an important chemical called hemoglobin that gives blood its red colour. The hemoglobin in blood delivers oxygen to your body.
White blood cells:
White blood cells (leukocytes), are bigger than red blood cells. When you are healthy, you have few white blood cells in your blood. When you are unwell your body produces more to fight and protect your body.
There are a few types of white blood cells that do different things to keep you well, they are:
Monocytes are white blood cells that fight infection by surrounding and destroying bacteria and viruses.
Helps wounds heal after an injury. Granulocytes also help prevent infection by surrounding and destroying germs found in your body.
There are two types of lymphocytes: B cells and T cells. B cells help make special proteins called antibodies that recognize bacteria or virus that has entered your body. Antibodies are very specific, and can recognize only a certain type of germ. Once the antibody identifies it, it destroys it. B cells can become memory cells that remember how to make the special antibody so that if the same germ infects you again, it can kill the germ even faster.
T cells also battle germs that invade the body, but instead of making antibodies, they work by making special chemicals that help fight the infection.