Development of the digestive system in the gut layers and in places mesenteries extend from the gut as double layers of peritoneum. Mesenteries provide a pathway for vessels, nerves, and lymphatics to the organs. Initially, the gut tube from the caudal end of the foregut to the end of the hindgut is suspended from the dorsal body wall by dorsal mesentery. Ventral mesentery, derived from the septum transversum, exists only in the region of the terminal part of the esophagus, the stomach, and the upper portion of the duodenum. The diaphragm divides the body cavity into the thoracic cavity and the abdominal cavity. It develops
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