Peristalsis
The oesophagus is a collapsed tube. How does food travel down a tube that is squeezed shut?
Figure to be added
Peristalsis
The oesophagus wall is muscular. Its contractions and relaxations make waves — peristalsis — that push the bolus forward. Peristalsis carries food from the oesophagus into the stomach.
Because it is driven by muscle, not gravity, food still reaches the stomach even if you swallow while lying down.