Respiratory System · NEET PG Preparation Physiology
During a maximal expiration, a subject reaches residual volume. At this point, the inward elastic recoil of the lungs and the outward elastic recoil…
Practice question from Respiratory System (NEET PG Preparation Physiology), with the correct answer and a step-by-step solution.
hard · MCQ · Q-4609F8
During a maximal expiration, a subject reaches residual volume. At this point, the inward elastic recoil of the lungs and the outward elastic recoil of the chest wall are related in which of the following ways?
- A.Lung recoil is zero; chest wall recoil is outward and maximal.
- B.Inward lung recoil equals outward chest wall recoil.
- C.Outward chest wall recoil is greater than inward lung recoil.Correct answer
- D.Inward lung recoil is greater than outward chest wall recoil.
Solution
At residual volume (RV), the subject is actively exhaling against the outward elastic recoil of the chest wall. The chest wall strongly tends to spring outward, while the lungs tend to collapse inward. Because RV is achieved by maximal forced expiration, the outward recoil of the chest wall exceeds the inward recoil of the lungs, and further expiration is prevented only by airway closure or muscle fatigue.
More from Respiratory System
- A 28-year-old male undergoes pulmonary function testing. His forced expiratory volume in one second (FEV1) is 80% of predicted, forced vita…
- A healthy medical student is breathing air at sea level. If her arterial blood gas analysis shows PaO2 = 100 mmHg, PaCO2 = 40 mmHg, and her…
- Which of the following regional differences characterizes a normal upright lung at the level of the functional residual capacity (FRC)?
- A patient with severe metabolic acidosis develops compensatory hyperventilation (Kussmaul breathing). Which of the following changes is pri…
Practise more Physiology
Sign up free for adaptive practice on this chapter, with instant feedback and hints on every question.
Start practising freeFree to start · No credit card needed