Human digestive system teeth, and also by the contractions of peristalsis, and segmentation. Gastric acid, and the production of mucus in the stomach, are essential for the continuation of digestion. Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of the gastrointestinal tract. This initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system. Most of the digestion of food takes place in the small intestine. Water and some minerals are reabsorbed back into the
Digestive system of humpback whales digest the chitin in the exoskeletons of krill and prey swallowed whole. The duodenal ampulla can be described as the atrium of the small intestine and is a dilated sac forming the beginning of the duodenum. The duodenum prepares many nutrients from the digested matter (chyme), for absorption, which takes place in the intestines, and is the principal site for iron absorption. Digestive system of humpback whales The digestive system of humpback whales ("Megaptera novaeangliae") is adapted to digest tiny crustaceans such as krill, plankton, and small fish (including herring and mackerel) which the whale filters from the ocean using