Nutrition Science and Everyday Application - beta v 0.1

THE DIGESTIVE SYSTEM 149
Figure 3.13. The digestion and absorption of nutrients in the small intestine.
Large Intestine
Most of the nutrients from the peanut butter and jelly sandwich have now been digested
and absorbed. Any components that still remain (usually less than ten percent of food
consumed) and the indigestible fiber move from the small intestine to the large intestine
(colon). A main task of the large intestine is to absorb much of the remaining water. Water is
present not only from the solid foods and beverages consumed, but also the digestive juices
released by the stomach and pancreas. As water is reabsorbed, liquid chyme becomes a
semisolid, referred to as feces. Feces is composed of undigested food residues, unabsorbed
digested substances, millions of bacteria, old cells from the lining of the GI tract, inorganic
salts, and enough water to let it pass smoothly out of the body.
Feces is stored in the rectum (a temporary holding area) until it is expelled through the
anus via defecation. No further chemical breakdown of food takes place in the large intestine