INFOGRAPHIC 3.1 Cells, Tissues, Organs, and Organ Systems Numerous cells representing every tissue type are organized to form organs and organ systems. Cells within the various organs of the digestive system produce substances that are needed to process the nutrients in the foods we eat into units that can be taken up (absorbed) by the cells lining the gastrointestinal (GI) tract. Those absorptive cells then export nutrients into the circulatory system for distribution to the rest of the body.
