Trachea: Structure, Function and Clinical Significance

Trachea or windpipe is a part of our respiratory system. The respiratory system comprises organs and tissues that help us in breathing. Airways, lungs and blood arteries are all part of it. The respiratory system begins with the nose and mouth and proceeds to the lungs via the trachea. Air enters the respiratory system through the nose and mouth, passing through the pharynx and larynx. A thin flap of tissue covers the entrance to the larynx and shuts spontaneously after swallowing, preventing food or drink from entering the trachea or windpipe. Trachea or windpipe are pipes that carry oxygen-rich air to your lungs. Carbon dioxide is also carried out of your lungs by them. In this article, we will study more about the functions, structure, microanatomy and clinical significance of trachea.

Key Terms: Respiratory System, Breathing, Pharynx, Larynx, Bronchioles, Lungs, Respiration

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Respiratory System

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The respiratory system is not only responsible for breathing but it also performs other activities involved in the respiratory system. Our body cells require a constant supply of oxygen for the metabolic activities that are required to maintain life. To provide oxygen and remove metabolic waste, the respiratory system collaborates with the circulatlory system. It also contributes to the control of blood pH.

• The upper respiratory tract and the lower respiratory tract are the two basic components of the respiratory system.
• Everything above the vocal folds is considered to be in the upper respiratory system, whereas everything below the vocal folds is considered to be in the lower respiratory tract, and the lower respiratory tract includes everything below the vocal folds. Both the tracts work together to perform respiration.
• The upper respiratory tract consists of the nasal cavity and sinuses both of which are in the area behind the nose. The nasal cavity is the space right behind the nose where outside air can enter the body.
• The sinuses are air chambers located behind the front of your skull that aid in the regulation of air temperature while you breathe.
• Air can also enter the body through the mouth, in addition to the nasal cavity. When air enters the body, it passes through the pharynx and larynx, which are located in the lowest region of the upper respiratory system.
• The lower respiratory tract begins with the trachea which is a tube that permits air to flow directly into the lungs.

Human Respiratory System

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What is Trachea?

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The trachea, commonly known as the windpipe, is a cartilaginous tube that links the larynx to the bronchi of the lungs, allowing air to pass through. It can be present in nearly all air-breathing organisms. The trachea separates into the left and right bronchi from the larynx.

• The trachea is an important element of our breathing system. It is made up of cartilage rings and lined with mucus-producing cells with thin hairlike projections (cilia).
• This mucus prevents allergens, dust particles and other debris from entering your lungs. The trachea works with the rest of our respiratory system to facilitate breathing.
• During inhalation the air moves from the nose and mouth into the trachea.
• The trachea empties into the left and right bronchi.
• Through the bronchi and into the bronchioles of our lungs.
• Into alveoli, which are tiny sacs in your lungs where your body swaps oxygen for carbon dioxide.

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Structure of Trachea

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Mentioned below is the structure of trachea:

• The trachea is a hollow, tube-like structure that connects the larynx (voice box) to the bronchi (two passages that link the trachea to the lungs). The trachea has an average length of roughly 11.8 cm. A male's trachea is normally longer than a female's trachea.
• A mucous membrane similar to that seen in the nasal cavity lines the interior of the trachea. Goblet cells in this membrane secrete mucus to help prevent bacteria and debris from entering the lungs.
• The trachea is also coated with cilia, which are small hair-like structures. These aid in the removal of mucus containing debris or germs from the trachea. The mucus is subsequently swallowed or spitted out.
• The trachea is mostly made of soft tissue, with some cartilage for support.
• The trachea runs parallel to and immediately in front of the oesophagus. The trachea's back is softer to allow the oesophagus to expand during eating.
• The C-shaped cartilaginous rings allow the trachea to gently collapse at the aperture, allowing food to flow down the oesophagus.

Structure of Trachea

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Microanatomy of Trachea

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A layer of interspersed layers of column-shaped cells with cilia lines the trachea. Goblet cells are unicellular intraepithelial mucus-secreting glands that protect, lubricate, and catch hazardous particles on the epithelium's surface. It consists of 16-20 tracheal cartilages anterolaterally and a fibromuscular wall posteriorly which is formed by the trachealis muscle, making the cartilages appear as incomplete C-shaped rings. The trachea's wall structure makes it sufficiently flexible and elastic to allow for temporary oesophagus expansion during swallowing.

Microanatomy of Trachea

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Functions of Trachea

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Mentioned below are the functions of trachea in our body:

• The trachea's principal purpose is to transport air to and from the lungs. A person would be unable to breathe if they did not have a trachea.
• In addition to delivering air, the trachea aids in disease defence. Mucus in the trachea aids in the capture of germs such as viruses and pathogenic bacteria before they enter the lungs.
• The trachea also serves to control the temperature of the air that enters and exits the lungs.
• On chilly days, the trachea warms and humidifies the air before it reaches the lungs.
• On hot days, the trachea aids in the cooling of the air through evaporation.

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Clinical Significance

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Inflammation and Infection: The majority of illnesses affecting the trachea are bacterial or viral infections, while irritants such as chlorine gas, sulphur dioxide and intense smoke can harm the tracheal lining and increase the incidence of infections.

• Chronic infection is facilitated by irritants such as frequent smoking and drinking.
• During chronic infection, the tracheal walls contain an excess of white blood cells; the number of blood vessels increases; and the walls thicken due to an increase in elastic and muscular fibres.
• Croup is a respiratory infection caused by the infection of the upper airway in the area of the larynx, with infection sometimes migrating into the lower airway to the trachea. It usually affects young children and is characterised by a severe cough, hoarseness, and trouble breathing.

Intubation: Intubation is the insertion of a flexible plastic tube into the trachea in order to maintain an open airway or to function as a tube for the direction of certain medications. It is widely used in severe injury, illness, or sedated patients to promote pulmonary ventilation, including mechanical ventilation, and to avoid suffocation or airway blockage. Intubation is generally assisted by locating the vocal cords and passing the tube between them into the trachea rather than the oesophagus using a suitable device.

Narrowing: Trachea gets narrower when there is an inflammation or scar tissue in the trachea, which makes it difficult to breathe.

• A tracheal contraction might be induced by intubation, tracheobronchial injury, or inflammation associated with granulomatosis with polyangiitis.
• Airway blockages can occur at any point along your airway. This is more likely to occur in children, who have smaller airways, and in those who have nerve and muscle disorders.
• The reason for a blockage determines how it is treated. Cancer-related blockages can be treated with surgery, chemotherapy, or radiation.
• A stent may be placed through the barrier. Benign lesions, such as scarring-induced constriction, are more likely to be surgically eliminated.

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Things to Remember

• The respiratory system helps your body in absorbing oxygen from the air so that your organs can function properly.
• The trachea is a very important part of our respiratory system that helps us in breathing, without the trachea one would not be able to breathe.
• The trachea is the major path for air to go from the upper respiratory tract to the lungs. As the air passes, trachea provides moisture and warmth to it before it enters the lung.
• The trachea lining contains a sticky mucus which traps foreign substances from entering our lungs.
• If a person is having difficulty breathing, it is possible that the trachea is affected therefore they should seek medical attention as soon as possible.

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