Difference Between Alveoli and Bronchi

What is Alveoli?

After the respiratory aeronautics courses, alveoli are the numerous tiny air sacs of the lungs, further separated as alveolar sacs. The alveoli in the mammalian respiratory system are referred to as pneumonic alveoli. The distance across the alveoli sac is typically 0.2-0.5 mm. Alveoli together resemble a bunch of grapes.

In a few human lungs, the full-scale conventional surface area of alveoli is roughly 70 m3. As a fundamental squamous epithelium, the respiratory film of the alveoli is also included. Furthermore, the typical limit of alveoli is to work with respiratory gas exchange. De-oxygenated blood travels from the heart’s right ventricle to the lungs via the pneumonic inventory route.

This blood transports carbon dioxide into the alveoli while taking oxygen from the air inside the alveoli. This creates oxygenated blood, which returns to the heart’s left office via pneumonic veins.

What is Bronchi?

Bronchi are little sections of the respiratory air course, and bronchioles are further split into individual alveoli. Typically, each lung contains roughly 30,000 bronchi. They don’t, however, have tendon rings to enclose the chamber. Smooth muscles, flexible connective tissue, and direct cuboidal epithelium with flask cells make up bronchi.

In addition, the respiratory flying courses include three bronchi. Lobular bronchi, terminal bronchi, and respiratory bronchi are the three types. Furthermore, lobular bronchi, also known as preterminal bronchi, branch off from the tertiary bronchi to form terminal bronchi that lead to an aspiratory lobule. Although terminal bronchi comprise fundamental cuboidal epithelium, challis cells are required.

They also develop the respiratory bronchi, which contain non-ciliated cells and lead to alveoli, and are suitable for gas exchange. In terms of limitations, the bronchi’s two primary functions are to carry air to alveoli via both lobular and terminal bronchi and to undergo gas exchange.

Difference Between Alveoli and Bronchi

  1. There are further divides in considerations, such as lobar bronchi and bronchioles. In any event, the alveoli have recently developed a pack blueprint known as the alveolar sac, which takes place in the acini.
  2. The alveoli have varied conditions resembling a sac or a cup. A bunch of grapes or raspberries are arranged in the alveolar sac. By and large, the bronchi appear to be a chamber and are not flexible. The state of an adjusted tree is developed by the complete bronchial divisions working together.
  3. Pneumocytes and pneumonocytes are found in the alveoli. Respiratory epithelial cells line the bronchi, containing ligaments, mucous layers, and smooth muscles.
  4. Regarding boundaries, the alveoli carry out vaporous commerce, whereas the bronchi carry out gaseous trade.
  5. The alveoli are little air sacs found near the completion of the bronchioles, while the bronchi begin around the fifth thoracic vertebra.

Comparison Between Alveoli and Bronchi

Parameters Of ComparisonAlveoliBronchi
DefinitionAny of the tiny air sacs of the lungsThe small branches of air tubes within the lung.
ShapeSac-like structureSac-like structure
DivisionsAlveolar sacsBronchioles
Starting PointLung parenchymaCarina is the point
where the windpipe detaches into the bronchi.
FunctionExchanges gasesCarries gases.


  1. https://www.atsjournals.org/doi/abs/10.1165/rcmb.2005-0180OC
  2. https://www.atsjournals.org/doi/pdf/10.1164/arrd.1979.120.1.151