Esophagus (or Oesophagus) and trachea are two very different parts or organs belong to two distinctive systems of the body. Oesophagus is a part of the alimentary tract while trachea is a main part of the respiratory system, but both these organs function as connectors of those respective systems. However, sometimes people commit the mistake of interchanging these two terms in referring. That may be due to carelessness or sometimes because of lack of awareness about these important body parts. Therefore, one should understand the simple differences between oesophagus and trachea, and this article would be important to follow in that regard.
Esophagus (or Oesophagus) is the muscular tube that connects pharynx with the stomach of the vertebrates. Oesophagus allows the food to pass from the mouth into the stomach. According to the location, the oesophagus has three main parts known as cervical (anterior most) part, thoracic (middle) part, and abdominal (Posterior most) part. Usually, the oesophagus is about 25 – 30 centimetres long. It has many types of cells and tissues incorporated. The mucosa is the inner most layer consisting no keratinised protective cells (stratified squamous epithelium), mucus secreting cells and smooth muscles. Next layer is the submucosa with mucus secreting oesophageal glands and some connective structures. The muscularis externa is the next outer layer composing mainly the muscles. Its composition changes with the location of the oesophagus; anterior part has striated muscles; middle part has smooth and striated muscles, and the posterior part has only smooth muscles. Adventitia is the outermost layer covering the oesophagus with loose connective tissues. There are three anatomically important constrictions in the oesophagus; the first one is the oesophageal inlet due to the pharynx and cricoids cartilage, the second constriction due to the aortic arch, and the third one is found where the oesophagus crosses the diaphragm. Finally, the oesophagus ends at the junction at the stomach known as the gastro-oesophageal junction.
Trachea is also known as the windpipe, and it is the tube that connects the lungs with the pharynx. Trachea allows the passage of air, being taken through nostrils, into the lungs. The trachea is about 10 – 16 centimetres long and contains an inner lining of pseudo stratified ciliated columnar cells. The goblet cells in the trachea are responsible for producing mucus in order to trap the foreign solid particles before reaching the lungs. Usually, the ciliated epithelium wafts those particles out of the respiratory system using cilia. The C-shaped cartilaginous structures (rings) are present in order to maintain the shape of the windpipe. The trachealis muscles are extremely important in facilitating a rapid airflow during coughing and sneezing by contracting the incomplete ends of the cartilaginous rings of trachea. The anterior end of the trachea is the larynx, and the epiglottis prevents food being entered into the respiratory tract. However, of all the vertebrates, only the air-breathing animals have trachea, i.e. the fish and related lower vertebrates do not have trachea.
What is the difference between Oesophagus and Trachea?
• Oesophagus is a part of the digestive system while trachea is a part of the respiratory system.
• Oesophagus is a muscular tube with varying shapes while trachea has a general internal shape with cartilaginous structures.
• Oesophagus is longer than trachea.
• The inner linings of the two structures are different.
• Trachea has cilia but not in oesophagus.
• Oesophagus connects the pharynx with the stomach while trachea connects the larynx with the lungs.