The section, EDAIC Multiple Choice Question and answer, covers a different topic each day with the intent that candidates can prepare one small topic each day, making steady progress in their exam preparation.

Question: The following statements refer to lung volumes:

A. Total lung capacity is the maximal volume of air that can be expired following a maximal inspiration
B. Tidal volume is 8–12 ml/kg in adults
C. Expiratory reserve volume is the maximal volume of air that can be expelled after tidal expiration and is usually over 3000 ml
D. Closing capacity is the lung volume where small air way begin to collapse on inspiration
E. In fit adults at altitude total lung capacity and vital capacity are equal

Answers:

1. 1. false
   2. true
   3. false
   4. false
   5. false

Explanation:

• The tidal volume is the volume of a normal breath and in an adult is around 500 ml .
• The functional residual capacity (FRC) is the volume of air in the lungs at the end of normal expiration with the subject in the standing position and is around 3000 ml in a normal adult. It can be considered as the volume of air in the lungs when the elastic recoil of the lungs is equal to the outward force of the chest wall and diaphragm tone. This is an important volume as it acts as an oxygen reserve, maintaining oxygenation of blood passing through pulmonary capillaries during expiration or breath-holding. FRC increases with subject height and in males. It is important to realise that it decreases approximately 1000 ml in the supine position due to the upward force of the abdominal contents.
• Inspiratory reserve volume is the volume that can be inspired over and above the normal tidal volume and equals approximately 2500 ml.
• Inspiratory capacity is the total volume that can be inspired above FRC and equals around 3000 ml.
• Vital capacity is the maximal volume that can be expired after a maximal inspiration and is around 4500 ml.
• Expiratory reserve volume is the additional volume that can be expired at the end of expiration and is approximately 1500 ml. Residual volume is the volume of air remaining in the lungs at the end of maximal expiration and is approximately 1000 to 1500 ml.
• Total lung capacity is the total volume of air in the lungs at the end of a maximal inspiration.
• Closing capacity is the lung volume where small airways begin to collapse on expiration. If this falls below FRC during tidal (normal) ventilation then it will result in hypoxaemia. Total lung capacity is the combination of vital capacity and residual volume, irrespective of atmospheric pressure.

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‘EDAIC Multiple Choice Question and answer’ covers a different topic each day with the intent that candidates can prepare one small topic each day, making steady progress in their exam preparation.