There are five main types of white blood cells. The picture shows the actual cells amongst red blood cells, along with handy diagrams to identify them.

The neutrophil we saw before ingests bacteria to destroy it.

Monocytes work in the same way but they enter organ tissues, they are found in the liver, lungs and skin.

Basophils release histamine and heparin to attract and aid other white blood cells, they are involved in allergic reactions.

Eosinophils also have a role in allergic reactions and kill parasites

Lymphocytes are the elephants of our immune system, they recognize and retain a memory of invading bacteria and viruses, allowing the body to remember how to attack a disease quickly and efficiently.