Did you know that the stomach can hold 2-4 liters of material? As the bolus or partially digested food enters the stomach, the stomach muscles begin to expand and if you eat enough, they can expand all the way down to around your bladder.
Just for reference, the stomach is a crescent shaped lopsided pouch that normally sits just under your diaphragm. The esophagus enters on the right side so that when we laugh and the stomach
contracts, we don't send food out & back up the other end. "Genius"!
The stomach is like an antiseptic holding tank where we kill any unwanted pathogens or bacteria present in the bolus. Remember our tube is exposed to the outside world and like a bouncer at a club we need to screen what makes it in.
Acidic gastric juices pour into the stomach and lower the PH to around 2. That is enough to burn through your hand. In addition to killing pathogens at a low PH, the stomachs gastric juices continue to breakdown food before passing it along to the small intestine.
Everyone has their role and the majority of protein digestion occurs in the stomach.
After this phase our mashed up partially digested food is now called Chyme. The stomach releases small amounts of chyme into the first section of the small intestine 2-3 teaspoons as a time. This is the beginning of Phase III "The Intestinal Phase"
... to be continued...