How does food move through the digestive system?
In a wave-like movement, called peristalsis, muscles propel food and liquid along the digestive tract. In general, there are six steps in the process of moving food and liquid through the digestive system: • The first major muscle movement is swallowing food or liquid. The start of swallowing is voluntary, but once it begins, the process becomes involuntary and continues under the control of the nerves. • The esophagus, which connects the throat above with the stomach below, is the first organ into which the swallowed food goes. • Where the esophagus and stomach join, there is a ring-like valve that closes the passage between the two organs. When food nears the closed ring, the surrounding muscles relax and allow the food to pass into the stomach, and then it closes again. • The food then enters the stomach, which completes three mechanical tasks: stores, mixes, and empties: • First, the stomach stores the swallowed food and liquid, which requires the muscle of the upper part of the st
