Answer to Question #20324 in Other Biology for srikar
why does food goes into our stomach even by eating in upside down position?
Food is actually pushed toward the stomach through the esophagus, an approximately 10 inch long and 1 inch in diameter (in adults) muscular tube leading to the stomach. The esophagus is lined with smooth muscle, a type of muscle that contracts involuntarily (without us making it contract). Food and water entering the esophagus does not drop down and fall into the stomach; instead it is pushed through by waves of contractions (squeezes) from the bands of muscles that encircle the esophagus (of course, gravity does help a little bit). These contractions are known as peristalsis. Once food or water reaches the end of the esophagus, a valve called a sphincter closes so it can't come back up. Peristalsis is so strong that it can actually enable a person to swallow food or water while upside down.