Do you know what are the alveoli? What is its function in the human body? You will find the answer in this article. The pulmonary alveoli, also called alveoli, are an essential part of the respiratory system that plays an important role in the breathing process. Here are the following more details about it: What h

j pulmonary alveoli?

The alveoli are very small air sacs located in the lower respiratory tract, which are a group of alveoli that form together to form inflatable grape-like structures that can expand and contract during inhalation and exhalation.

In general, the lower respiratory system consists of the trachea, which branches into two tubes known as the bronchi, where one of these tubes connects to the right lung and the other to the left lung.

Inside the lungs, the bronchi branch into smaller tubes called bronchioles. The ends of these bronchioles are connected to hundreds of millions of alveoli by alveolar ducts.

Installation of the walls of the alveoli

The pulmonary alveoli are surrounded by a network of tiny blood vessels called pulmonary capillaries, which have a thin, elastic wall.

In general, the walls of the alveoli are composed of two basic types of very thin epithelial cells, which include the following:

1. Type I pneumocytes

They are flat cells that cover most of the outer surface of the pulmonary alveoli, which are the barrier responsible for the process of gas exchange between the alveoli and the capillaries.

2. Type II granular pneumocytes

They are cells smaller than pulmonary cells of the first type and responsible for the secretion of fatty substances that help reduce the surface tension of the alveoli wall to facilitate gas exchange.

It is worth noting that the inner cavity of the pulmonary alveoli contains another type of cells called alveolar macrophage, which are movable macrophages, whose function is to swallow foreign bodies that enter the lungs, such as: bacteria, carbon particles, damaged blood cells, and dust.

pulmonary alveolar function

The alveoli are the last part of the lower respiratory tract in which the inhaled air rests, and in which the exchange of oxygen and carbon dioxide between the air and the bloodstream takes place.

Thus, the process of gaseous exchange between blood and air is the primary function of the pulmonary alveoli, where the alveoli give the blood oxygen and take carbon dioxide from it.

Gaseous exchange process

When a person breathes, that is, during the inhalation process, the air travels from the upper respiratory tract, which is the nose or mouth, through the trachea, then to the bronchi, and then reaches the alveoli in the lungs.

The alveoli and capillaries have a common membrane called the air-blood barrier. This barrier allows gases to pass freely from the alveoli into the capillaries and vice versa.

When the inhaled air reaches the pulmonary alveoli, the capillaries take oxygen from the air in the alveoli and combine it with red blood cells, then transfer it to the bloodstream and then distribute it to all tissues of the body.

In return, the alveoli collect carbon dioxide from the capillaries, and put it out of the body during the exhalation process.

Normally, about 0.3 liters of oxygen is transferred from the alveoli into the blood, and a similar amount of carbon dioxide is excreted from the blood into the alveoli per minute.

Diseases affecting the pulmonary alveoli

Like all other organs of the body, the alveoli can be damaged and this damage can affect their vital function, which in turn may lead to the occurrence of multiple respiratory problems, the most important of which are:

1. Emphysema

It is an irreversible damage to the walls of the alveoli, which leads to a decrease in the efficiency of the gas exchange process and thus difficulty in breathing. This disease usually results from many causes, including: smoking, environmental pollutants, or the result of some genetic factors.

2. Pulmonary Alveolar Proteinosis

It is a rare lung disease that causes obstruction of the alveoli as a result of the accumulation of some fluids containing fatty and protein substances, and this disease usually causes difficulty breathing.

3. Pulmonary alveolar microlithiasis

It is a pulmonary disorder that occurs as a result of the deposition of small stones consisting of the accumulation of a compound called calcium phosphate, which causes damage to the alveoli, causing multiple respiratory problems, including: persistent coughing and shortness of breath.

4. Other diseases

Other diseases that can affect alveolar function include

Pneumonia.

Pneumoconiosis is a group of problems caused by inhaling coal dust.

Acute respiratory distress syndrome.

pulmonary edema

Tuberculosis.

Lung Cancer.

Chronic obstructive pulmonary disease.