The role of alveolar surfactant is to
[ Select ]
increase
decrease
the alveolar surface tension and to
[ Select ]
increase
decrease
alveolar compliance.

Question

The role of alveolar surfactant is to 
[ Select ]
increase
decrease
 the alveolar surface tension and to 
[ Select ]
increase
decrease
 alveolar compliance.

BlackTom AI · Accepted Answer

Alveolar surfactant reduces surface tension at the air–liquid interface of the alveoli, so it decreases alveolar surface tension and thereby increases alveolar compliance.

1) Relevant concepts:
- Surface tension: cohesive forces at the liquid lining of alveoli that tend to collapse them inward. Higher surface tension increases the pressure tending to collapse a spherical alveolus.
- Law of Laplace for a sphere: P = 2T / r, where P is the pressure needed to keep the alveolus open, T is surface tension, and r is radius.
- Compliance: C = ΔV / ΔP — the lung’s volume change per unit pressure change. Lower pressure required to expand the lung (smaller P) yields greater compliance.

2) Step-by-step reasoning:
- Surfactant molecules (mainly dipalmitoylphosphatidylcholine) insert into the alveolar fluid film and disrupt cohesive forces, lowering T.
- By Laplace’s law, if T decreases, the inflation pressure P required to prevent alveolar collapse decreases proportionally (P ∝ T).
- With a smaller pressure needed to achieve a given volume (ΔP reduced), compliance (ΔV/ΔP) increases.

3) Numerical illustration:
- If T initially = 50 units, for a given radius r the required P = 2·50/r = 100/r.
- If surfactant lowers T to 25 units, P = 2·25/r = 50/r — the pressure halves, so the same volume change requires half the pressure, doubling compliance.

4) Why the correct answer is correct:
- Because surfactant lowers T, collapsing pressure and work of breathing fall; lungs are easier to inflate (increased compliance).

5) Why the other options are incorrect:
- Saying surfactant increases surface tension is opposite its biochemical action; that would increase collapsing pressure and reduce compliance.
- Saying surfactant decreases compliance misunderstands mechanics: reducing T lowers required pressure and therefore increases compliance, not decreases it.

Conclusion: The correct choices are “decrease” (alveolar surface tension) and “increase” (alveolar compliance), matching the provided answer.

The role of alveolar surfactant is to [ Select ] increase decrease the alveolar surface tension and to [ Select ] increase decrease alveolar compliance.Multiple dropdown selections

Similar Questions

A patient comes in and has a pO2 of 96mmHg, a pCO2 of 40mmHg, and 50% saturation of carbon monoxide. Would you expect this patient to show chemoreceptor-mediated hyperventilation?

According to the PhysioEx Respiratory Exercise: If bronchial radius is reduced, then FEV1 should [ Select ] increase stay the same decrease .

In emphysema, tissue destruction results in [ Select ] decreased increased lung compliance. This leads to problems with lung [ Select ] recoil inflation and a(n) [ Select ] increased decreased residual volume (RV).

In advanced emphysema, exhalation becomes active and requires the use of [ Select ] internal intercostals and abdominal muscles external intercostal and diaphragm . This is associated with [ Select ] increased decreased airway resistance.

When the pCO2 of the blood increases, the production of H+ [ Select ] increases decreases but only [ Select ] H+ O2 CO2 is capable of crossing the blood-brain barrier to elicit a response by central chemoreceptors.

Normally, we are not concerned about the most prevalent gas in the atmosphere around us, [ Select ] carbon monoxide nitrogen , because [ Select ] it is relatively insoluble in plasma water it does not affect respiratory rate .

What is the purpose of not ventilating for 1 minute and prioritising other management when the asthmatic patient losing cardiac output?

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler