Food-pipe

Oesophagus - the oesophagus is a muscular-walled tube about 20-25 cm long, through which food passes from the pharynx to the stomach at a rate of 5-7 cm per second.

In the oesophagus, there is an upper and a lower sphincter (upper and lower oesophageal sphincter), between which is the tubular section of the oesophagus.

The passage of food and liquid through the oesophagus is not only assisted by gravity, but also by a peristaltic movement in waves, produced by complex neural control of the muscles in the oesophageal wall.

The part behind the wall in the oesophagus contracts with the help of muscles, bringing the wall down where the muscles are still relaxed.

By repeating this process, the bite reaches the end of the oesophagus, the lower circular sphincter. As the sphincter relaxes, the bite is released into the stomach.

Esophageal sphincters normally prevent the contents of the stomach from flowing back into the esophagus or throat.