The waste of the digestive tract is moved through the colon by peristalsis. The rectal contents are emptied via 2 sphincters, one voluntary and one involuntary, through the anus. The appendix is located at the junction between the small intestine and the large intestine. The colon is highly vascularized to facilitate absorption into the bloodstream. Look at these views of the colon through the fiberoptic.
Bacteria play a very important role in the digestive processes of many animals.
Symbiotic bacteria and protozoa can aid in the digestion of cellulose by producing cellulase. Animals cannot produce this enzyme. Microorganisms synthesize certain vitamins, including Vitamin K. Microorganisms aid in the digestion of many foods in our diet as well.