A muscular tube connecting to the throat (pharynx) with the stomach is known as the Oesophagus. It is approximately 25cm long, but variations have been recorded that range between 10–50 cm long depending on an individual height. The Oesophagus is also lined by a moist pink tissue known as mucosa. The muscles situated in the sides of the Oesophagus squeeze and relax during swallowing, hence forcing the food down towards the stomach. The motion of pushing down the food with the help of the muscles is called ‘peristalsis’. The Oesophagus basically is situated behind the trachea (windpipe) and the heart and is in front of the spine. Before entering our stomach, the Oesophagus passes through the diaphragm.
The sphincter is basically a ring of muscles that surround and serve guard to an opening tube, for example the anus or the openings of the stomach. There are over 50 types of Sphincters in the human body. The Oesophagus has two types of sphincter – the upper Oesophageal sphincter and the lower Oesophageal sphincter. The upper Oesophageal sphincter is a bundle of muscles that is situated at the top of the Oesophagus. The muscles of the upper Oesophageal sphincter are always under conscious control and are mostly used during breathing, eating and vomiting. They basically keep secretions and food from going down the windpipe. The lower Oesophageal sphincter similarly is a bundle of muscles that is situated at the low end of the Oesophagus, where it further meets the stomach. It basically prevents the acid and stomach contents from travelling backwards from the stomach. Unlike the upper Oesophageal sphincter, the lower Oesophageal sphincter is not under voluntary control.
In the process of digestion, the Oesophagus has the simplest function of all. The Oesophagus is not involved in breaking down the food that is swallowed, but it merely conveys the chewed food from the mouth to the throat, further to the stomach. It usually starts functioning at the back of the oral cavity, and runs through the hole in the diaphragm to the stomach. From the mouth to the stomach, the movement of the food is done in a wavelike motion to force it along. This wave like motion makes it possible for a person to eat or drink even if they are upside down. The Oesophagus is basically divided into three parts, known as cervical, abdominal and thoracic. The secondary phase of digestion occurs after the muscles work to get the food down to the stomach.
The sphincters are situated at the upper and lower ends of the Oesophagus. Except the swallowing process these muscles remain closed. The stomach contents make their way into the Oesophagus when the lower sphincter does not function properly. Such a condition is known as heartburn or acid reflux and it can be identified when a person experiences a burning feeling or a sharp pain in the chest. A person suffering from gastro Oesophageal reflux disease experiences similar symptoms. It usually occurs due to an irreversible malfunction of the lower sphincter or commonly known as a hiatus hernia. Similarly, the laryngopharyngeal reflux disease occurs when the acid prevailing in the stomach makes its way to the throat. The symptoms usually include coughing, sore throat, hoarseness and difficulty in swallowing food. If gastro Oesophageal reflux disease is not treated, it can lead to ulcers in the Oesophagus which can further give rise to a condition known as Barrett’s Oesophagus. The person or the patient with such condition is at higher risk for developing Oesophageal cancer.
The irregular, uncoordinated and powerful contractions of the Oesophagus are known as the Oesophageal spasm. There are basically two main types of Oesophageal spasm.
Nutcracker Oesophagus: In nutcracker Oesophagus spasm, the Oesophagus is basically squeezed in a co-ordinated way, similar to the way the food is gulped down the Oesophagus normally. But the squeezing process is very strong and these contractions moving through the Oesophagus cause extreme pain.
Diffuse Oesophageal spasm: In diffuse Oesophageal spasm, the squeezing of the muscles is irregular and uncoordinated, which prevents the food from reaching the stomach. Thus, the food gets stuck in the Oesophagus.
Scientifically, the disruption of the nerve activity that helps in the swallowing action of the Oesophagus leads to Oesophageal spasm. It is usually triggered when very hot or very cold food is consumed. Most people having such conditions suffer from chest pain that at times spreads outward to the back, neck, jaw or arms. The pain is very similar to that of a heart attack. Other symptoms usually include difficulty or inability to swallow liquid or food, pain while swallowing or a burning sensation in the chest.