African Journal of Respiratory Medicine
The structure and function of alveoli

Short Communication - (2022) Volume 17, Issue 11

Harry Hill*
*Correspondence: Harry Hill, Department of Pulmonology, Varna Medical University, Bulgaria, Email:

Received: 01-Nov-2022, Manuscript No. ajrm-22-84531; Editor assigned: 03-Nov-2022, Pre QC No. ajrm-22-84531(PQ); Reviewed: 17-Nov-2022, QC No. ajrm-22-84531; Revised: 22-Nov-2022, Manuscript No. ajrm-22-84531(R); Published: 29-Nov-2022, DOI: 10.54931/1747-5597.22.17.51

Department of Pulmonology, Varna Medical University, Bulgaria


The lungs of the human body contain small air sacs called alveoli and these work with the exchange of oxygen from the lungs into the veins. Find out about the portrayal of the alveoli, their capabilities in the respiratory framework, and how oxygen moves from the respiratory framework into the circulatory framework.


The alveoli are where the lungs and the blood trade oxygen and carbon dioxide during the course of taking in and breathing out. Oxygen took in from the air goes through the alveoli and into the blood and goes to the tissues all through the body. Carbon dioxide goes in the blood from the body’s tissues and goes through the alveoli to be inhaled out. Respiratory bronchioles lead into alveolar conduits which are profoundly fixed with alveoli. Each respiratory bronchiole leads to somewhere in the range of two and eleven alveolar pipes. Every pipe opens into 5 or 6 alveolar sacs into which groups of alveoli open. The quantity of alveoli in the human lung expanded dramatically during the initial long term of life yet kept on expanding but at a diminished rate through puberty.1

The lung alveoli are the inflatable like air sacs located at the distal closures of the bronchial tree. There are upwards of 700 million alveoli in every lung, where they work with vaporous trade of oxygen and carbon dioxide between breathed in air and the circulatory system. The pneumonic alveolus is a sac generally 0.2 mm to 0.5 mm in width. These alveoli are situated at the finishes of air ways in the lungs. Some of the time, individuals contrast alveoli structures with the presence of a raspberry or a “lot of grapes.” The walls of the alveoli are extremely thin. This lets oxygen and CO2 pass effectively between the alveoli and vessels, which are tiny veins. Oxygen can pass from the alveoli to the vessels on the grounds that the centralization of oxygen is lower in the vessels than in alveoli. Essentially, CO2 moves the alternate way on the grounds that the centralization of carbon dioxide is lower in the alveoli than in the vessels.2

Human lungs contain around 480 million alveoli. This produces 50 to 75 m2 (540 to 810 sq ft) of surface region. Alveolar cells have a few distinct sorts as per capability. Two significant sorts are pneumocytes (Type I cells) or pneumonocytes (Type II cells). They are found in the alveolar wall and an enormous phagocytic cell known as an alveolar macrophage that moves about in the lumens of the alveoli, and in the connective tissue between them. The significant cell type tracked down on the alveolar surface, covering around 95% of the surface region, are slender, expansive cells known as squamous (type I) alveolar cells, otherwise called type I pneumocytes. The dainty walls of these cells consider fast gas dissemination between the air and blood, and in this manner consider gas trade to happen. Type II cells in the alveolar wall contain secretory organelles known as lamellar bodies that breaker with the cell layers and emit pneumonic surfactant. This surfactant is a film of greasy substances that decrease alveolar surface pressure. Consistently delivered by exocytosis, the covering keeps the alveoli from breakdown. The liquid covering is created by the body to work with the exchange of gases among blood and alveolar air, and the sort II cells are normally found at the blood-air boundary.3,4


The alveoli perform one of the body’s most significant capabilities. They are the passage through which oxygen enters the circulation system. They are additionally the essential way that the side-effect carbon dioxide leaves the body.


The Authors are very thankful and honoured to publish this article in the respective Journal and are also very great full to the reviewers for their positive response to this article publication.

Conflict of Interest

We have no conflict of interests to disclose and the manuscript has been read and approved by all named authors.


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