Question

Discuss the esophagus and include one usual abnormal finding

Answer 1

In humans, oesophagus is about 25 cm long tube like structure with a diameter of about 2 cm. Oesophagus is contineous with the pharynx superiorly and joins the stomach inferiorly. Oesophagus curves upwards before its opening into the stomach. This forms a sharp angle which is thought to prevent the backflow of acidic content of the stomach into the oesophagus. It has two sphincters, the upper oesophageal sphincter and the lower oesophageal sphincter. Upper sphincter prevents air passing into the eosophagus during inspiration. The lower oesophageal sphincter prevents the reflux of gastric contents into the oesophagus.

Structure: Oesophagus has four layers of tissue, i.e., peritoneum (outermost), muscle layer, submucosa and mucus layer (innermost). It is supplied by oesophageal arteries and branches of the inferior phrenic arteries and the coeliac artery. The venous drainage of the oesophagus is into the azygos veins, hemiazygos veins and left gastric vein.

Functions: When food is masticated in the mouth and bolus is formed, the presense of the bolus stimulates the peristalsis which moves the bolus through the oesophagus into the stomach. Usually cardiac sphincter (lower oesophageal sphincter) is closed which prevents the reflux of gastric acid into the oesophagus. The innermost layer of the oesophagus is mucosa, which secrets mucus lubricating the walls of the oesophagus and helps in passage of bolus towards the stomach during peristalsis.

Common disorder: The most common abnormal finding with the esophagus is GERD (gastroesophageal reflux disease). In this condition, the lower eosophageal sphincter does not close properly, which allows the content of the stomach to leak back, or reflux, into the esophagus. This is caused by persistent reflux of acidic gastric juice into the oesophagus, which causes irritation, inflammation and ulceration with pain. If this persists for longer duration, it can cause damage to the esophagus. In chronic conditions, haemorrhage occurs due to erosion of blood vessels. Chronic inflammation leads to severe damage, and secondary healing with fibrous tissue formation.

GERD may be caused due to increase in intra-abdominal pressure in certain conditions, e.g. during pregnancy, obesity and constipation. This condition may also be caused due to high acid content in gastric juice, lower levels of gastrin hormone and due to presense of hiatus hernia.

Other problems of the oesophagus include  oesophageal cancer and eosophagitis.