Question at position 9 What causes air to flow into the lungs during inspiration?Intrapleural pressure becomes positive.Intrapleural pressure is higher than intra-alveolar pressure.Intra-alveolar pressure is lower than atmospheric pressure.The pressure in the lungs is higher than atmospheric pressure.Atmospheric pressure is equal to intra-alveolar pressure.

Question

Question at position 9 What causes air to flow into the lungs during inspiration?Intrapleural pressure becomes positive.Intrapleural pressure is higher than intra-alveolar pressure.Intra-alveolar pressure is lower than atmospheric pressure.The pressure in the lungs is higher than atmospheric pressure.Atmospheric pressure is equal to intra-alveolar pressure.

BlackTom AI · Accepted Answer

This question asks about the mechanism that drives air into the lungs during inspiration. 
Option 1: 'Intrapleural pressure becomes positive.' Intrapleural pressure is normally negative relative to atmospheric pressure to keep the lungs expanded; if it became positive, it would actually push against the chest wall and hinder inhalation, not promote it.
Option 2: 'Intrapleural pressure is higher than intra-alveolar pressure.' If intrapleural pressure were higher than the pressure inside the alveoli, the transpulmonary pressure would be reduced or reversed, making inspiration difficult; in practice, the crucial comparison is between intra-alveolar and atmospheric pressure, not the intrapleural versus alveolar pressure, for the initial flow during typical inspiration.
Option 3 (the correct one): 'Intra-alveolar pressure is lower than atmospheric pressure.' During inspiration, the diaphragm and intercostal muscles expand the thoracic cavity, increasing lung volume and lowering intra-alveolar pressure below atmospheric pressure, causing air to flow down its gradient into the lungs.
Option 4: 'The pressure in the lungs is higher than atmospheric pressure.' If alveolar pressure were higher than the atmosphere, air would be pushed out, not drawn in, during inspiration, which contradicts the normal inhalation process.
Option 5: 'Atmospheric pressure is equal to intra-alveolar pressure.' When these pressures are equal, there is no net air flow; this situation corresponds to no inspiratory drive at that moment.
In summary, the key concept is that air moves from higher to lower pressure, and during inspiration the intra-alveolar pressure drops below atmospheric pressure, drawing air into the lungs.

Similar Questions

When pressure inside the alveolus exceeds atmospheric pressure _________________.

During the inspiratory portion of a respiratory cycle, the airway resistance is reduced because the distending force exerted by the positive Blank ______ pressure keeps the smaller airways that lack cartilage from collapsing.

The difference in pressure between the alveolar and intrapleural spaces is known as the Blank ______.

During heavy breathing, expiration through the lungs is _. During normal breathing expiration is _.

Which of the following best describes movements of the throracic wall?

下列哪项最能描述胸壁的运动？

The work of breathing is described as the total work required to move the chest wall and expand the lungs. Which of the following factors does not contribute to the work of beathing?

Which of the following statement most accurately describes the relationship between the contracting muscles, the pressure or resistance change, and the movement of air during quiet breathing in a healthy individual.

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