Chapter 11, Problem 1RQ

Summary Introduction

Introduction:

Aging is an irreversible process that occurs despite optimal nutrition, genetic background, surroundings, or activity patterns. The bodily functions decrease as a person ages and the organ functions are also affected. Lungs are also affected likewise, as it reaches the final growth stage at the age of 20 years and after 25 years of age the quality of the lungs gradually decreases.

Answer to Problem 1RQ

Correct answer:

As an individual ages, the vital capacity decreases.

Explanation of Solution

Justification for the correct answer:

Option (D) states that as an individual ages, the vital capacity (VC) decreases. This is a true statement as VC is the maximum amount of air that a person can expel from their lungs after inhalation. VC is equal to the total lung capacity (TLC) minus the reserve volume (RV). Hence with age, the reserve volume increases, which leads to a decrease in VC with increasing age. Hence, option (D) is correct.

Justification for the incorrect answers:

Option (A) states that as an individual ages, the residual volume decreases. This is false, as with age, the alveoli enlarge and the airway starts to close. Hence, the residual capacity generally increases with age. So, it is an incorrect option.

Option (B) states that as an individual ages, the expiratory reserve volume increases. This is not true, as with an increase in residual volume (RV), the expiratory reserve volume (ERV) decreases due to reduction in chest wall compliance and the increase in air trapping. So, it is an incorrect option.

Option (C) states that as an individual ages, the functional residual capacity decreases. This is a wrong statement because it is the volume that remains in the lungs after the elastic recoil balances the expansion of chest wall. With age, this elastic recoil decreases and is not able to balance the chest wall expansion. Therefore, the functional residual capacity increases as a person ages. So, it is an incorrect option.

Hence, options (A), (B), and (C) are incorrect.

Conclusion

Thus, it can be concluded that as an individual ages, the vital capacity (VC) decreases due to the increase in reserve volume.