What happens when food enters the stomach?

Everyone knows that the process of digestion takes place in the stomach. BUT, what exactly is going on in it? What processes are involved in this? Let’s analyze everything in more detail.
The digestion process is not only a chemical but also a physical process. During digestion, food is digested and absorbed.
During the digestion process, food enters the stomach. To do this, she needs to go through the cardiac sphincter. Then it is mixed with gastric juice.
The gastric juice contains: digestive enzymes (pepsin and renin), as well as hydrochloric acid.
In the stomach, proteins are broken down into amino acids, polypeptides. The process of digestion of dairy products takes place with the support of renin.