They contain connective tissue fibers that give them their characteristic elasticity and are composed of type I flat cells and type II cube-shaped cells. The main function of the alveoli is to make the gaseous exchange between the air and the blood.
What is of alveoli
Alveoli are the terminal diverticules of the bronchial tree, in which the gaseous exchange between inspired air and deoxygenated blood is made. They are sacks coated on their inner wall by a sticky white liquid. They can reach a millimeter in diameter and contain a tense agent.
They have a single opening to get the gas out and enter, this action is controlled by the action of a smooth muscle sphincter. The walls of the alveoli are known as alveolar septums and provide a large surface of gaseous exchange.
Characteristics of the alveoli
Among the main characteristics of the pulmonary alveoli we have:
- They consist of an endothelium of a very thin layer that facilitates the exchange of gases.
- They have a diameter of approximately 0.05 and 0.25 mm.
- They are rounded or polyhedral.
- The Alveoli separates each other by the interalvetol partition, which is a common wall between the two. On the edge of these partitions are basal rings formed by smooth muscle cells.
- On the outside of the alveoli are the blood capillaries, who with the alveolar membrane form a single membrane where the gaseous exchange is carried out.
- In the alveolar membrane, there are cells called alveolare macrophages, which are responsible for the defense and cleaning of the alveoli.
- Two types of cells are found in the alveoli, the type I that mediate in the exchange of gases and the type II that have secret and immune functions.
- They have a series of pores located in the interalvelum partitions called Kohn pores, which allow the alveoli to communicate with each other and circulate the air between them.
Role of alveoli
The main function of alveoli is to allow the exchange of gases, a vital process for breathing, as it allows oxygen to enter the bloodstream to be transported to the different tissues of the body.
They are also involved in removing carbon dioxide from the blood during inhalation and exhaling processes.
What’s the relationship between alveoli and the lungs?
The alveoli are found inside the lungs. Each adult lung has about 150 million alveoli, adding a total of 300 million alveoli between the two lungs. If we stretch them they can cover about 75 square meters.
When we breathe, the air enters the body through the trachea, runs through a series of tunnels inside the lungs, known as bronchials and bronchials, and at the end of these, the alveoli are found, where the gas exchange will take place.