The lymphatic system is made up of T cells, B cells, antibodies, and platelets. When the skin is scratched, platelets travel to the wound. They then try to mend the wound, and stop the bleeding. The T cells are the cells that attack all diseases that enter the body. B cells are the cells that manufacture antibodies. Antibodies are proteins that isolate pathogens, foreign substances, so that T cells can attack and destroy it.

In today's world there are virtually millions upon millions of diseases. Viruses or bacteria cause most diseases. Viruses are considered non-living parasites, which enter healthy cells, release their own DNA and cause the healthy cell to begin manufacturing other virus bodies. Since viruses are not alive, antibiotics cannot kill them; therefore, most viruses have no cure. When a virus enters the body, antibodies are sent to isolate the virus, then B cells arrive to infiltrate and finally kill the virus.

Bacteria on the other hand are a living parasite. It performs the same functions as a virus, but it is considered a living parasite. Since bacteria are living, antibiotics can be used to kill it. There are three types of bacteria, bacilli, cocci, and spirili. Bacilli bacteria are rod shaped and usually appear alone, only occasionally found in-groups. Cocci are spherical bacteria that occur in chains of cells, singularly, or in clusters that resemble a bunch of grapes. Spirili are spiral shaped bacteria, they are curved, and resemble a comma. Bacteria are considered deadly due to the fact that it can reproduce very quickly.