Multiple choice

Which of the following statements is FALSE regarding the surfactants?

  1. It is a fraction part of a lipoprotein called dipalmitoyl phosphatidyl-choline.

  2. It is synthesized by alveolar type II cells.

  3. Alveolar surface area decreases during expiration, the surfactant decreases the surface tension at a constant rate.

  4. When surfactant density gets decreased during expansion, surface tension initially rises rapidly, then begins to fall until it reaches the starting point.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During expansion, i.e. during the act of inspiration,  the surfactant density decreases which makes the surface tension strong enough to make the alveoli collapse again. So, the surface tension will constantly rise not as the option states that it will increase, then decrease.

Keep practicing — related questions