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.
Stomach and Duodenum. The stomach is a J-shaped sac connecting the esophagus above and the small intestine below. The first part of the small intestine is known as the duodenum. The stomach varies considerably in size, shape and position but lies in the upper central part of the abdomen behind the lower ribs. Although it is a single organ, several different parts of the stomach exist: the fundus, body, antrum and pylorus.