Phagocytes: find and eat bacteria, viruses, and dead/ injured body cells. There are three types of phagcytes; granulocyte, macrophage, and dendritic cell.
Macrophage: alert rest of immune system of invaders(bacteria or viruses)
T cells: the "T" comes from the Thymus where the t cell matures. two types; helper t cells and killer t cells.
Helper t cells: activate b cells and killer t cells. the phagocyte preforms antigen presentation.
Antigen Presentation: where mkacrophage or dendritic cell "eats" invader and gives piece of the invader called teh antigen to he helper t cell so that so that it can recognize it and activate the b and killer t cells.
killer t cell: attacks ankd kills cells infecting the body and the cancer cells.
B cells: take teh antigen from the helper t cell and connects to it so that it sends off a signal to the rest of body, and then int produces protein by hleper t cell to fully activate then splits in two cells: plasma cells and b memory cells.
Plasma cell: produces antibodies that respond to antigen adn are released so they can find virus and kill it.
Memory cells: have a long life span so it can remember "intruders" so that the 2nd time you are affected the t and b cells can activate faster and the virus or bacteria is wiped out befoer the human has any symptoms.