Acinus

Acini are small alveolar bronchioles in the human lungs. They are a group of cells that together make up the portion of the respiratory system involved in gas exchange. In the article we will consider the main features of their structure and function.

The structure and composition of the acinus

The acini is a group of alveoliocytes - small lung cells in which gas exchange occurs. Each alveolar bronchiole is divided by septa into several lobules, each of which has a diameter of about 0.5 mm. The walls of the alveoli are formed by epithelial cells tightly adjacent to each other, the thickness of which does not exceed 0.05 mm. Each cell contains a small number of air-filled sacs (alveoli).

The main components of acinos are alveolocytes. Their walls contain multiple folds formed due to flattening, which creates a large surface for gas exchange. Each alveolus is equipped with endothelial cells, which create a barrier between the bloodstream and the internal environment of the body. Acini also include smooth muscle cells located in the walls of the bronchi and histiocytes, which provide protection.

Functions of the acinus: participation in respiratory mechanisms

The functional significance of acius is that they take part in the breathing process, providing the function of gas exchange between blood and air in the alveoli. Alveolic cells release and absorb oxygen and carbon dioxide. The intensity of oxygen exchange depends on the number of acini elements per square meter of lung tissue, as well as on the gas exchange surface area in each of them.

One acini is flat in shape, and the total gas exchange area on its surface is approximately 8 square centimeters. Typically a person can breathe approximately 60% to 90% of their lung volume through this structure in the airway because the alveulicular volume of gases can be greater overall within a single unit of time. The alveal membrane provides a mechanism for the diffusion of gases, while the villi of the epithelial membrane actively move gases in the plane of the leaf.

The mechanism of alveulollar respiration consists of a number of processes, thanks to