Why is the alveoli lined with tissue fluid?

Why is the alveoli lined with tissue fluid?

Alveoli are lined by a fluid called surfactant. This fluid maintains the shape of the air sac and helps keep it open so that oxygen and CO2 can pass. At this point, the oxygen molecules move through a single layer of lung cells in the alveolus, then through a single cell layer in a capillary to enter the bloodstream.

Why must the internal surface of the alveoli be kept moist?

An alveolus is made from many spherical structures, resembling a bunch of grapes. This structure significantly increases the surface area exposed to the air. The alveoli must remain moist with water as gases, such oxygen and carbon dioxide, can only move across membranes when dissolved in water.

Why is it important that the alveoli in the lungs are lined with simple squamous epithelium?

Explanation: Alveoli are the site of gas exchange in the lungs. Because rapid diffusion of gases is necessary between the capillaries and the alveoli, a very thin epithelial layer is needed. As a result, alveoli use simple squamous epithelium so that gases can easily diffuses to and from the bloodstream.

What are the alveoli lined with?

The alveoli are lined with a single layer of squamous epithelial cells, which allow for easy diffusion of vital gases.

What happens if the alveoli are lined with water like fluids?

If the alveoli were lined with waterlike fluids, the surface tension would be sufficiently high to cause the emptying of smaller-diameter alveoli into larger ones, according to the Laplace relationship P = 2 T/r, where P = alveolar pressure, T = surface tension, and r = radius of the alveolus.

What is the function of the surfactant in the alveoli?

Alveoli are lined by a fluid layer known as a surfactant which maintains the shape and surface tension of the air sac. By maintaining surface tension, there is more surface area through which oxygen and CO2 molecules can pass.

What is the function of type 2 alveolar epithelium?

Type II cells have two functions: (1) They repair the alveolar epithelium when the squamous cells are damaged, and (2) they secret pulmonary surfactant that coat the alveoli inner surfaces. Surfactant is an oily substance of phospholipids and protein that lowers the surface tension of alveolar fluid and helps keep the alveoli open. 8

What is the structure of the alveolus composed of?

More than 95 percent of the wall of an alveolus is composed of a thin layer of protoplasm comprising alveolar epithelial cells (type I cells). The honeycomblike structure of lung parenchyma is formed mainly by the walls of contiguous protoplasam comprising alveolar epithelial cells (type I cells).