Glossary

Cytochromes: Specialized enzymes within mitochondria and other cell structures. Different cytochromes play impor­ tant roles in metabolizing toxic substances, drugs, and other chemicals, as well as in producing adenosine triphos­ phate (ATP). Cytokines: A family of molecules, produced primarily by cells of the immune system, that regulate cellular interac­ tions and other functions. Many cytokines play impor­ tant roles in initiating and regulating inflammation. Cytoplasm: The substance filling the cell, including the cytosol as well as mitochondria, endoplasmic reticulum, and other cell structures (organelles) but excluding the nucleus.