MICROANATOMY

Detailed explanation-1: -One of the remarkable phenomena in the process of respiration is the role of the fluid coating the walls of the alveoli of the lungs. This fluid, called a surfactant, lowers the surface tension of the balloon-like alveoli by about a factor of 15 compared to the normal mucous tissue fluid in which they are immersed.

Detailed explanation-2: -It is established that pulmonary surfactant reduces surface tension at the air–water interface in the alveoli, thereby preventing collapse of these structures at end-expiration. In this manner, surfactant reduces the work associated with breathing.

Detailed explanation-3: -Alveoli are microscopic balloon-shaped structures located at the end of the respiratory tree. They expand during inhalation, taking in oxygen, and shrink during exhalation, expelling carbon dioxide. These tiny air sacs are the site where gas exchange between inspired air and the blood takes place.

Detailed explanation-4: -Surface tension tends to collapse the alveoli, but this is countered by a kind of “coating” that covers the alveolar surface called surfactant. Surfactant reduces the surface tension of water, keeping the alveoli open so that we can breathe easily.

Detailed explanation-5: -Pulmonary surfactant is essential for life as it lines the alveoli to lower surface tension, thereby preventing atelectasis during breathing.