High School Biology : Understanding Respiratory Organs

Study concepts, example questions & explanations for High School Biology

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Example Questions

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Example Question #11 : Respiratory System

What is the primary and unique role of surfactant in the lungs?

Possible Answers:

Lubricating the bronchioles 

Waterproofing the interior of the lungs

Disinfecting the interior of the lungs 

Lowering the surface tension of alveoli

All of these answers 

Correct answer:

Lowering the surface tension of alveoli


Alveoli, like most bodily structures, are part of an aqueous environment, making them subject to the surface tension of water. Surfactant lowers surface tension, allowing the alveoli to expand with much less pressure than they would against full surface tension. As a result, inspiration of air requires less effort, making it more energetically efficient. 

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