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.
Normally, a muscular valve (pylorus) between the stomach and small intestine holds food in the stomach until it is ready for the next stage in the digestive process. In pyloric stenosis, the pylorus muscles thicken and become abnormally large, blocking food from reaching the small intestine.