What is the role of the esophagus in digestion? This is a common question among students taking biological studies. First it’s important to note that digestion is the process by which the body metabolizes or converts consumed foods into nutrients that can be absorbed and used by various body organs. Esophagus is the only part of the body whose only function is to transit food, saliva and liquids from the mouth to the stomach. This occurs through coordinated contractions of its muscular lining on the walls.
This process is automatic hence you may not be able to feel the flow of food unless you swallow something that is too large or eat too quickly. In a healthy body, the muscular layers are pinched together at the lower and upper ends by sphincter muscles.
So, what happens when you swallow food? The upper sphincter muscles immediately relax to allow food to pass from the mouth to esophagus before proceeding to the stomach. More importantly, the muscles rapidly close to prevent any leakage of food from stomach back to the esophagus and mouth. In fact, these muscles have the capacity to facilitate swallowing of food even when someone is in an upside-down position or lying down.
If you experience stomach upsets, the brain will automatically initiate bleaching. This basically refers to the process of releasing gases from the stomach. In such cases, the sphincter muscles will relax to allow outflow of the gases. Some small particles of food may flow upwards with the gases. This process is referred to as reflux. To counter this, the muscle lining on the walls of the esophagus will quickly contract in a bid to squeeze food particles back into the stomach.
The manner and rate at which the muscles contract and relax is governed by the nervous system. Sympathetic division and vagus nerve are its main nerve supply. When swallowing food, a nerve signal is transmitted by the vagus nerve to the upper sphincter muscles. Also, the swallowing sequence is largely dependent on the nerves intrinsic to the esophagus.
How long is the esophagus? Studies show that it’s normally 9.5 inches long. Mucosa, the soft moist tissue lining, facilitate smooth and interrupted flow of food and protect the digestive tract from enzymes and acids that are produced in the stomach during digestion.
To promote functionalism of esophagus, it’s recommendable to eat balanced diet that is rich in all nutrients and drink ample amounts of water to prevent dehydration.