Question

Which of the following is not a characteristic of alveoli?

• A. They shuttle air to and from the lungs
• B. They maintain the shape and surface tension of the air sac
• C. They are arranged in clusters
• D. They sit at the end of the respiratory tree.

Answer 1

The correct option is B

They maintain the shape and surface tension of the air sac

The correct option is B.

Explanation for the correct option:

1. Small air sacs called alveoli have a balloon-like form.
2. Their function is to transport carbon dioxide and oxygen molecules into and out of your bloodstream.
3. Surfactant is the fluid that is produced by the cells lining alveoli.
4. This liquid helps to prevent the collapsing of the air sac open and maintains its shape so that the exchange of gases can occur.

Explanation for the incorrect options:

Option A:

1. Alveoli are thin-walled sac-like structures that are responsible for the exchange of gases.
2. Hence, the statement “They shuttle air to and from the lungs” is correct.

Option C:

1. Alveoli are the tiniest respiratory system components.
2. All around the lungs, there are clusters of alveoli that resemble a bunch of grapes.
3. Hence, the statement “They are arranged in clusters” is correct.

Option D:

1. Alveoli are located at the tips of the respiratory tree's branches.
2. This phrase refers to the network of airways that resembles a tree and carries air to the lungs.
3. Hence, the statement “They sit at the end of the respiratory tree" is correct.

Final answer: The incorrect statement is “They maintain the shape and surface tension of the air sac”