Sense of course of a working life first attested 1803. v. 1590s, to charge at a tournament, from career (n.). The meaning move rapidly, run at full speed (1640s) is from the image of a horse passing a career on the jousting field, etc. Related: Careered; careering.
Contractions of the stomach muscle, called peristaltic waves, grind, crush and mix the food producing a liquefied substance called chyme.. The pyloric sphincter separates the stomach from the duodenum. This valve keeps food and gastric juices in the stomach until liquefied enough to proceed into the duodenum.
This bicarbonate neutralizes the acid from the stomach in the chyme and protects the duodenum from the acid. When the chyme enters the duodenum, cells in the duodenum release the hormones intestinal gastrin, secretin, cholecystokinin, and gastric inhibitory peptide. Intestinal gastrin initially stimulates the stomach.