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.
The diaphragm is a sheet of muscle that separates your belly (abdomen) from your chest. The hernia bulges through the diaphragm at a place called the hiatus. This is the opening in the diaphragm that the esophagus passes through. The esophagus is the tube that connects the throat to the stomach.