With the help of our nose we inhale the air, from there the air travels through the nose and enters the trachea, which is also known as the windpipe. The trachea is divided into two parts, one enters our right lung, whereas the other enters the left lung. These two tubes that the trachea splits into are known as Bronchi.

Bronchus is one of the large tubes in our body that leads from the human trachea to the lungs. In each lung there is one large bronchus situated, that further branches out into smaller Bronchi within our lungs. The Bronchi basically carry air in and out of the lungs. The bronchus is located between the trachea and the lungs.

The main left and right primary bronchus is one of the air passages into the lungs. Similarly, the lower left and right lobe bronchus is also one of the air passages into the lungs. The tertiary Bronchi are also referred as segmental Bronchi and they basically branch out from the secondary Bronchi, which descends from the mainstream Bronchi. Further extending lower into the lungs, they become smaller and break up into primary Bronchioles. Each of the tertiary bronchus serves the particular bronchopulmonary segment. The left lung consists of nine tertiary bronchus, whereas the right lung consists of ten tertiary Bronchi. The respiratory epithelium (thin tissue forming the outer layer of a body) is surrounded by a smooth muscle layer. The layer is made up of two muscular ribbons that are in opposite directions. The irregular plates of hyaline cartilage in turn surround these layers of smooth muscles, which helps in keeping the airway open.

The Bronchioles branch into sacs and alveolar ducts. The alveolar ducts or air sacs are basically the primary units for the exchange of oxygen and carbon dioxide in our lungs. We humans, have approximately 480 million alveoli.

The main functions of the Bronchi are – allowing air to pass and preventing infection.

The trachea splits into two parts and the inhaled air enters the Bronchi. From the Bronchi, the air passes through the further divisions of the Bronchi, which are referred as Bronchioles. The bronchus acts as a passage for the air to pass from. The exchange of air is mainly down by the alveolar air sacs. When the Bronchi functions in a normal condition, it ensures that the airway remains patent, so that air can easily pass freely.

Besides allowing the air to pass, the Bronchi also perform other functions. Various types of cells line the Bronchi, like goblet or mucus and ciliated cells. The ciliated cells have cilia, which is basically a hair like projection that usually moves in a co-ordinated fashion, at one end of the cell. The goblets cells are large and they secrete mucus. The cilia prevent and trap the pathogens from coming in when the air enters through our nose. The mucus and cilia that are present in the Bronchi prevents the pathogens from entering into our lungs. It is an important function, as if pathogens enter into our lungs, it could lead to various different respiratory diseases.

The diseases associated with the Bronchi are:

Asthma: The people suffering from asthma have a hypersensitive respiratory system, which constricts at times and thus reduces the airflow, which in turn causes problems in breathing properly. During asthma attacks, the person may experience wheezing as the air is forced to pass through the small air passages.

The causes of asthma are the pollution in the air, tobacco smoke, cold air, exercises.

Acute Bronchitis: Bronchitis is basically the inflammation of the Bronchial tubes, which are the primary way for the air to pass to the lungs. It occurs when the windpipe within the lungs become inflamed due to irritation or infection. It is usually caused due to bacterial or viral infection in the lungs, or usually after a person has just been cured from a bout of respiratory disease. That is because the immunity level of the person has lowered down and now they are more prone to such kind of disease.

The symptoms associated with Bronchitis are shortness of breath, the mucus or sputum is green or yellow in colour, fatigue, cough, chest pain.

Chronic Bronchitis: It is an inflammation of the Bronchial tubes that carry air to our lungs. It causes cough that often brings up the mucus, as well as shortness of breath, chest tightness, or even wheezing. It is a type of chronic obstructive pulmonary disease. In this condition the inflamed Bronchi produces a lot of mucus that leads to cough, and difficulty in breathing. The most common cause of this disease is smoking. The other causes include breathing in dusts or other fumes for a long period of time. It is basically a long term condition that usually keeps coming back and never fades off completely.

Sinusitis: It occurs due to the inflammation of the sinus cavity present in our respiratory system. It basically occurs in a person who has just been cured from cold, cough or any other allergic reactions.

The symptoms associated with sinusitis are facial pain, headache, nasal congestion, sore throat, cough, and fatigue.

Bronchospasm: It is basically the contraction of the smooth muscle present in the bronchus or the Bronchiole. It is caused due to injury or irritation in the mucosa in the airway, by infection or maybe due to an allergy. The symptoms of bronchospasm include severe cough and wheezing.