Oesophagus

The oesophagus is part of the digestive system.

Function of theoesophagus

The function of the oesophagus is to pass food which has been chewed in the mouth down towards the stomach where digestion continues. The oesophagus carries foods actively via contraction of its muscles, a phenomenon called " peristalsis". It has a sphincter at its upper end which prevents reflux of food. It does not have the sphincter at its lower end (the cardia of the stomach folds forming a barrier against reflux, a type of functional sphincter).

Structure of theoesophagus

The oesophagus is located between the pharynx and cardia of thestomachand is a tubular thoracic organ measuring approximately 25 centimetres long and 2 to 2.5 centimetres in diameter.

It has three narrowings :

• at the cricoid cartilage;
• at the point where it passes the arch of the aorta;
• and when it passes through the diaphragm.

Theoesophagus is composed of several layers, from outside inwards :

• an adventitia formed from a connective tissue membrane separating the oesophagus from the other organs;
• an external longitudinal muscle layer;
• an internal circular muscle layer;
• a submucosa composed of a dense vascularised and innervated connective tissue;
• and a mucosa composed of an epithelium, a basal lamina and connective tissue.