What's the role of the stomach in digestion process?

Big part. Digestion starts with good chewing & allowing saliva to do its part.Once food is in the stomach, stomach acid continues to work to break the food down into smaller packages to help remove the nutrients.Other parts of digestion happen after food has left the stomach and is exposed to other digestive juices from pancreas and gallbladder.Many hormones and chemicals interact.Good digestion needs all.