Question

What is the role of alveoli in the lungs?

Answer 1

Alveoli are little air sacs in the lungs that resemble a bunch of grapes. Pulmonary alveoli are another name for these. They primarily facilitate gas exchange. Nephrons are divided into two types- renal corpuscle and renal tubule. The majority of these are related to blood filtration.

Complete answer:
At the end of the bronchioles are tiny air sacs (tiny branches of air tubes in the lungs). During the act of breathing in and out, the alveoli are where the lungs and blood exchange oxygen and carbon dioxide. Breathing in oxygen from the air flows through the alveoli and into the bloodstream, where it travels to all of the body's tissues. Carbon dioxide moves through the bloodstream from the body's tissues to the alveoli, where it is exhaled.

Alveoli are microscopic air sacs in your lungs that absorb oxygen and keep your body functioning. Alveoli are the workhorses of your respiratory system, despite their minute size.

At the end of your bronchial tubes, you have around 480 million alveoli. The alveoli expand to take in oxygen when you breathe in. The alveoli contract to expel carbon dioxide as you exhale.
The basic unit of ventilation is the alveolus, which is a hollow chamber found in the lung parenchyma.

The alveoli are made up of an epithelial layer and an extracellular matrix that is bordered by capillaries, which are small blood vessels.
Each alveolus is surrounded by capillaries and serves as a location for gas exchange via diffusion.

Pulmonary surfactant is secreted by type II cells in the alveolar walls. This fatty material layer helps to minimise alveolar surface tension, which prevents the lungs from collapsing.

Alveolar macrophages are found on the inside surfaces of alveolar air cavities, alveolar ducts, and bronchioles. These work as mobile scavengers, engulfing foreign particles in the lungs such dust, germs, carbon particles, and blood cells caused by traumas.

The respiratory system begins when we inhale air via our mouth or nose and ends with alveoli. The oxygen-rich air passes via the trachea and into one of the two lungs via the right or left bronchus, respectively. Carbon dioxide molecules, which are produced as a by-product of cellular respiration, diffuse back into the alveolus and are ejected from the body by the nose or mouth. Alveoli expand during inhalation as the diaphragm contracts, creating a negative pressure in the chest. As the diaphragm relaxes during exhale, the alveoli rebound (spring back).

Note:-
The pulmonary alveolus is a small sac with a diameter of 0.2 to 0.5 mm. In the lungs, alveoli are found at the extremities of air channels. Alveoli structures are sometimes compared to the appearance of a raspberry or a "bunch of grapes". There are approximately 480 million alveoli in the average adult lung.