It's basically the process by which we have an involuntary movement of the muscle that lines the esophagus and this propels, this moves our food down into our stomach. Now, once the food is inside our stomach, the stomach plays several important roles. Firstly, it basically acts to store the food. So it has a certain capacity, about two liters of capacity, to basically store that food. Now, the stomach also consists of specialized types of cells and these cells basically secrete different types of enzymes and different types of substances. For example, a cell known as the parietal cell.