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Trachea Function

Trachea is the first portion of the lower respiratory tract, and is also called windpipe in layman's terms. Read this story to find out the importance of trachea in our body.
Bhakti Satalkar
The trachea, also known as windpipe, is a strong muscular tube located in front of the esophagus. It connects the nose and mouth to the lungs. It is an important part of the respiratory system. At the lower end, it splits into the left and right bronchi that enter into the lungs. Thus, it connects the pharynx and larynx to the lungs.
In most adults, it is approximately 3.9 to 4.7 inches (10 to 12 cm) long, and less than an inch in diameter. There are approximately 15 to 20 C-shaped cartilage rings embedded into it. These rings protect the trachea, and help maintain the airway.
The muscles of the trachea are connected to these incomplete rings by ligaments. The trachea is the primary air canal, hence dysfunction of the trachea can impair respiration. Any damage caused to the trachea can potentially be life-threatening.

Function of the Trachea in the Respiratory System

➺ The main function of the trachea is to let the air flow into the lungs. It helps in respiration. It widens and lengthens slightly as you inhale. It returns to its resting size as you exhale. The inward airflow from the trachea branches off to the two bronchi and lungs.
The cartilages ensure that the larynx and the trachea do not collapse, when there is no air in them.
➺ The walls of the trachea are made up of four layers of tissues. Mucosa, the innermost layer, is lined with goblet cells that produce mucus. The mucus helps moisten the air as it passes through the respiratory tract. Sometimes, foreign particles like dust or bacteria escape the hair of the nasal cavity.
The mucus helps trap such inhaled particles. The trapped particles are then either passed through the larynx and the pharynx into the stomach, or are expelled as phlegm.
➺ The muscle present in its posterior wall allows the trachea to contract and reduce its diameter. This reduces the size of its lumen. The air can be thrown out with increased pressure. This helps get rid of the cough.
➺ The trachea is connected to the same tubing system, which allows a person to swallow. However, the trachea has an evolved mechanism, which prevents choking and respiratory failures. When an object blocks it, the person may experience breathlessness.
With the coughing reflex, the trachea helps to throw out the object. The muscles of the trachea contract and promote coughing. The movement of the ciliated epithelial cells also helps throw out the object.
➺ Trachea indirectly helps digest the food. As you swallow food, the esophagus expands. The incomplete cartilage rings (C-shaped, and not round) of the trachea allow it to contract, and thus, promote the expansion of esophagus into its space.
➺ The connective tissues in the adventitia, the outermost layer of the trachea, loosely connect it to the surrounding soft tissues. Because the trachea is loosely anchored, it is able to move within the neck and thorax.
This is beneficial for the lungs that expand and contract during respiration. Thus, the trachea is so designed and situated that it promotes breathing as well as digestion.

Dysfunction of Trachea

Inflammation of the linings of the trachea (tracheitis), inflammation of the mucous membranes of the trachea and bronchi (tracheo-bronchitis), a defect in the cartilage, an infection, etc., can adversely affect the function of the trachea.
When the connective nerve tissues in the trachea degenerate, the condition is called tracheomalacia. Infections to the trachea can cause tracheomegaly. This can lead to dry hacking cough.
In case of any abnormalities in the trachea, different tests may be carried out to ascertain the exact cause of the problem. The treatment may vary according to the cause.