Function Of The Bronchi: Anatomy And Functions Of This Organ In The Respiratory System

The body provides energy by combining the oxygen in the air with the carbohydrates present in the food you eat.

The body uses a complex system, including the mouth and nose, trachea, larynx, bronchial tubes, bronchioles, and alveoli, to breathe in air, extract needed oxygen, and remove nitrogen and other substances required. The body does not need it.

The bronchial tubes separate from the windpipe and carry air to the lungs. They are delicate hoses that connect the throat to the lungs.

When you breathe through your mouth or nose, air travels down your throat and into a chamber called the larynx, which closes the air passages when you swallow. It also allows you to cough and make vocal sounds.

From the larynx, air passes through a single cartilaginous tube, called the trachea, and then into the bronchial tubes, which complete the journey from the throat to the lungs.

The tracheobronchial tree is the anatomical and functional segment of the respiratory system that conducts air from the upper airways to the lung parenchyma.

It comprises the trachea and intrapulmonary airways, including the respiratory bronchi, bronchioles, and bronchioles.


Different histological features are seen at each level and serve specific purposes.

The trachea and bronchi have cartilaginous walls.

The bronchi undergo multiple divisions and eventually give rise to the terminal bronchioles, which lack cartilage.


The main bronchus is about 2.5 cm long, shorter, and more comprehensive in diameter than the left main bronchus.

The junction of the right bronchus with the right lung is at the level of the fifth thoracic vertebra.

The principal or right primary bronchus is the branch that leads to the right lung and is subdivided into the upper, intermediate, and lower secondary bronchi.

At each of the lobar bronchi points of origin, the bronchial lymph nodes are located.

The secondary bronchi are subdivided, first into tertiary bronchi in several ten. Each of them gives rise to the subsegmental bronchi, which finally are subdivided into much smaller branches, which are called bronchioles.

The left main bronchus is twice as large as the right, with a length of about 5 cm.

The level of insertion of the left bronchus with the lung is carried out at the level where the sixth thoracic vertebra is located; this structure moves below the aortic arch and crosses the esophagus, the thoracic duct, and the descending aorta on the side previous.

Like the right main bronchus, the left one is also divided into two lobar bronchi, the upper and lower lobar bronchus; these are subdivided into eight tertiary or segmental bronchi, which continue to divide into smaller tubes to become subsegmental bronchi that then a, in turn, they are divided into bronchioles.

The bronchi have cartilaginous rings surrounding them and are C-shaped; the smaller bronchial tubes are provided with cartilaginous sheets with irregular shapes instead of the circles; these sheets serve as support.

These structures are in charge together with the smooth muscle bands; they control the lumen diameter in the bronchi when the inhalation and exhalation processes are carried out in the respiratory cycle.

Role of the bronchi in the respiratory system

The bronchial tubes are really like little hoses. They branch out from the windpipe to carry air to the lungs.

When they reach the lungs, they divide into those smaller branches, called bronchioles, which then, in turn, connect to tiny sacs, called alveoli, which clump together like grapes and carry out the actual transfer of oxygen into the bloodstream.

An average person has a tennis court-like surface area of ​​alveoli within the lungs, exchanging gases between the airways and the bloodstream.

Each bronchus, or bronchial tube, is designed to resist collapse and provide a constant air flow.

Cartilage and smooth muscle provide structure, protection, and function for the air passages.

The inner surface of each bronchus is lined with mucous glands and tiny cilia, hair-like structures designed to filter dust and other foreign particles from the air as it passes through the bronchi.

The central airways also have cilia to trap dust and mucus-generating membranes to remove any foreign material.

The primary function of the primary bronchi is to carry oxygen-rich air into the lungs during the inhalation process and allow air containing carbon dioxide to exit the lungs and into the windpipe through exhalation.

The bronchi are also the connection between the other organs of the respiratory system and the lungs.

The cartilaginous walls help maintain their shape during breathing, preventing them from collapsing. In contrast, the mucous lining and the cilia prevent foreign particles, such as dust, from entering the lungs.