Oesophagus – the oesophagus is a muscular tube about 20-25 cm long, through which each mouthful of food travels from the throat to the stomach at a speed of 5-7 cm per second.
The oesophagus has an upper and a lower sphincter (the upper and lower oesophageal sphincters), with the tubular section of the oesophagus between them.
The passage of food and fluid through the oesophagus is helped not only by gravity but also by wave-like, so-called peristaltic movements, which the muscles in the oesophageal wall produce under complex nervous control.
The part of the oesophagus behind the mouthful contracts with the help of the muscles, pushing the mouthful further down, where the muscles are still relaxed.
As this process repeats, the mouthful reaches the end of the oesophagus, the lower circular sphincter. When the sphincter relaxes, the mouthful passes into the stomach.
The oesophageal sphincters normally prevent the stomach contents from flowing back into the oesophagus or the throat.
