Question

16. Which of the following statements concerning alveoli would be correct? SELECT ALL THAT APPLY!!

a. Pulmonary surfactant of the alveoli is secreted by Type II alveolar cells.

b. When intra-alveolar pressure becomes greater than atmospheric pressure expiration will occur.

c. The walls of the alveoli are very thin and are surrounded by a network of capillaries so that air and blood are separated by only a very thin respiratory membrane.

d. Alveoli are the site of gas exchange in the lungs. e. The wall of the alveoli is composed primarily of simple squamous epithelium.

Answer 1

Answer 16:

a. Pulmonary surfactant of the alveoli is secreted by Type II alveolar cells.

Answer a. The above statement is “correct”.

Pulmonary surfactant which are lipoprotein material are secreated by type II Alveolar cells. It is responsible for reducing the surface tension in the alveoli.

b. When intra-alveolar pressure becomes greater than atmospheric pressure expiration will occur.

Answer b. The above statement is “correct”.

When intra alveolar pressure is positive i.e. intra alveolar pressure is greater than atmospheric pressure, air flows out from the higher pressure alveoli into the lower pressure atmosphere.

c. The walls of the alveoli are very thin and are surrounded by a network of capillaries so that air and blood are separated by only a very thin respiratory membrane.

Answer c. The above statement is “correct”.

Alveoli have an excellent blood supply and provides very large surface area. It is surrounded by a dense network of capillaries for exchange of gases between capillary blood vessels and the alveoli. It is separated by blood-air barrier which is a very thin membrane.

d. Alveoli are the site of gas exchange in the lungs.

Answer d. The above statement is “correct”.

Alveoli have an excellent blood supply and provides very large surface area. It is surrounded by a dense network of capillaries for exchange of gases between capillary blood vessels and the alveoli and it is where the exchange of gases happens through diffusion.

e. The wall of the alveoli is composed primarily of simple squamous epithelium.

Answer e. The above statement is “correct”.

Simple squamous epithelial aka alveolar cells makes the walls of the alveoli. Since it is a single layer of squamous cells it helps in diffusion of gases in the lungs.

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