Stomache to small intenstine


One thing I have been wondering about and I’m hoping someone here can explain

how does the transition from the stomach to the small intestine work? I assume its a sphincter, but if I eat something, and it is supposed to sit and break down in the stomach, then I eat something else later, how does it distinguish between broken-down ready to digest matter and fresh matter? Is it just that anything liquid enough to flow through is fine? Does it just continue breaking down as it continues through the small intestine? Or does the frequency of eating impact digestion?


Human Digestive System - Wikipedia


In case anyone wants a TL;DR to the answer:

When the pyloric sphincter, or valve opens, chyme enters the duodenum where it mixes further with digestive enzymes from the pancreas, and then passes through the small intestine

TL;DR: Tummy has door at end.