When we talk about reflux, it is key to understand how our body actually works. So, here’s an at-a-glance guide to the oesophagus.
Your oesophagus is an important part of the digestive system – it is a muscular tube that takes food from the back of your mouth to the stomach.
The oesophagus is also called the gullet or food pipe and, along with the mouth, stomach and intestines, is part of the gastrointestinal tract.
NOTE: In the US, it has the spelling of ‘esophagus’ without the ‘o’.
The oesophagus is a muscular tube, about 20-25cm long, with a sphincter (acting like a valve) at each end.
The oesophagus passes through the diaphragm – the dome-shaped muscle that separates our chest and abdomen – through the oesophageal hiatus opening.
At the top of the oesophagus is the upper oesophageal sphincter and the lower oesophageal sphincter is at the bottom of the tube, slightly above the stomach.
When you swallow food, the upper oesophageal sphincter relaxes and opens to allow food to pass from the pharynx (throat) into the oesophagus. It then immediately closes, preventing flow of food back into the mouth.
Then through an action called peristalsis – wave-like muscle contractions – food is moved down the oesophagus towards the stomach. Oesophageal motility refers to contractions occurring in the oesophagus, which propel the food toward the stomach.
The lower oesophageal sphincter relaxes to allow food down into the stomach and then closes to stop contents refluxing back into the oesophagus.
Inside the oesophagus
The oesophagus has four layers. Firstly, it is lined by moist pink tissue called mucosa made up of flat squamous cells that look similar to fish scales. Most of the oesophagus is lined by squamous mucosa.
Another layer is the submucosa – a thick, loose fibrous layer connecting the mucosa to the muscularis. The muscularis (muscle layer) contains fibres that are circular and longitudinal.
The outer layer of the oesophagus, the tunica adventitia, is composed of loose fibrous tissue that connects the oesophagus with neighbouring structures.
Oesophagitis is an inflammation of the inner lining of the oesophagus. Symptoms can include difficulty or pain when swallowing, sore throat, hoarse voice, heartburn, nausea and chest pain.