What Are The Alveoli?

Alveoli are a part of the respiratory system. These small air sacs sit at the end of the bronchial tube and are located in bunches all through the lungs.

Though they are microscopic but are known as the workhorse of the respiratory system. They are just a single cell thick, permitting the entry of oxygen and carbon dioxide (CO2) between the alveoli and veins called vessels.

One cubic millimetre of lung tissue contains around 170 alveoli. While all outnumber can differ, there are actually a million alveoli inside the human lungs spreading over a surface zone of about 70 square meters. It is made up of two different types of cells-

  1. Type I pneumocytes

    – These cells are responsible for the exchange of oxygen and carbon dioxide.

  2. Type II pneumocytes

    – These cells work to repair damage to the alveolar lining as well as a secrete surfactant.

Where Is Alveoli Located?

The alveoli are located in the lungs.
Human beings have two lungs — a left lung and a right lung — which fill up nearly all of the chest cavity. A lung has a spongy texture and may be considered as an elastic bag filled with millions of tiny air chambers called alveoli. If the walls of the alveoli could be spread out flat, they would cover about half a tennis court. The somewhat bullet-shaped lungs are suspended within the rib cage. They extend from just above the first rib down to the diaphragm, a muscular sheet that segregates the chest cavity from the abdomen. A thin, tough membrane called the visceral pleura covers the outer surface of the lungs.
The heart, blood vessels, and oesophagus (the tube connecting the mouth and stomach) lie between the two lungs.

Fact File

EACH ALVEOLAR DUCT IN THE LUNGS SUPPLIES ABOUT 20 ALVEOLI. THE VERY THIN WALLS OF EACH ALVEOLUS CONTAIN NETWORKS OF TINY BLOOD VESSELS CALLED PULMONARY CAPILLARIES. GAS IS INTERCHANGED BETWEEN THE BLOOD IN THESE CAPILLARIES AND THE GAS IN THE ALVEOLI.

Working Of Alveoli

The breathing process has three stages involved.

  • moving air all through your lungs or ventilation
  • exchange of oxygen-carbon dioxide or dissemination
  • siphoning blood through your lungs or perfusion

The alveoli get the oxygen you take in and discharge the active waste or carbon dioxide you breathe out. As it travels through veins in the walls of alveoli, your blood takes the oxygen from the alveoli and gives carbon dioxide.

Together, they make up a large structure to do the breathing, both the time when you’re very still and when you are working out. The alveoli spread a surface that estimates more than 1,076.4 square feet (100 square meters).

This vast surface is vital to process air in order to get oxygen to your lungs. Your lungs take in about 1.3 to 2.1 gallons (5 to 8 litres) of air every moment. At the point when you’re very still, the alveoli send 10.1 ounces (0.3 litres) of oxygen to your blood.

To push the air in and out, your stomach and different muscles help make the pressure inside your chest. At the point when you take a breath, pressure drops in your muscle, which is less than the air pressure outside. At the point when you inhale out, the lungs and alveoli come back to their typical size.