Accepts electrons from cytochrome c, ultimately transferring them to oxygen, forming H2O. in the process, 2 protons are pumped across the membrane. Complex IV is a terminal oxidoreductase, meaning that it transferes the elctrons to the terminal electron acceptor, which, in this case, is O2.
White blood cells called lymphocytes originate in the bone marrow but migrate to parts of the lymphatic system such as the lymph nodes, spleen, and thymus. There are two main types of lymphatic cells, T cells and B cells.
According to About.com, the B-cell lymphocytes contained in the lymph nodes activate when an antigen is present, and antibodies are produced to fight that particular antigen. Additionally, the T-cell lymphocytes also aid in the destruction of these harmful pathogens and promote cell-mediated immunity.