Q.101 If the vital capacity (VC) of an individual is 4900 ml, the tidal volume (TV) is
500 ml, and the inspiratory reserve volume (IRV) is 3300 ml, the expiratory reserve
volume (ERV) of the individual is ________ml. (in integer).
The expiratory reserve volume (ERV) is 1100 ml. This value is calculated directly from the standard vital capacity formula used in respiratory physiology.
Vital Capacity Formula
Vital capacity (VC) represents the maximum volume of air that can be exhaled after maximal inhalation. Multiple sources confirm the formula VC = tidal volume (TV) + inspiratory reserve volume (IRV) + expiratory reserve volume (ERV).
Rearranging gives ERV = VC – TV – IRV.
Step-by-Step Calculation
Given VC = 4900 ml, TV = 500 ml, and IRV = 3300 ml:
ERV = 4900 – 500 – 3300 = 1100 ml.
This matches typical adult ERV values of 1000-1200 ml.
Lung Volume Definitions
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Tidal volume (TV): Air moved during normal breathing (~500 ml).
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Inspiratory reserve volume (IRV): Extra air inhaled beyond TV (~2500-3300 ml).
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Expiratory reserve volume (ERV): Extra air exhaled beyond TV (~1000-1200 ml).
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Vital capacity (VC): Sum of TV, IRV, and ERV (~4000-5000 ml in adults).
No options are provided in the query, but the integer answer aligns with CSIR NET-style fill-in-the-blank questions on pulmonary function.
Vital capacity, tidal volume, and reserve volumes form core concepts in respiratory physiology for CSIR NET Life Sciences preparation. This guide explains how to calculate expiratory reserve volume (ERV) when vital capacity (VC) is 4900 ml, tidal volume (TV) is 500 ml, and inspiratory reserve volume (IRV) is 3300 ml.
Understanding Pulmonary Volumes
Pulmonary volumes measure air displacement in lungs during breathing. Key components include:
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Tidal volume (TV): Normal breath volume, typically 500 ml.
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Inspiratory reserve volume (IRV): Maximum extra inhalation after normal breath, often 2500-3300 ml.
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Expiratory reserve volume (ERV): Maximum extra exhalation after normal breath, usually 1000-1200 ml.
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Vital capacity (VC): Total exhaleable air after max inhalation.
These values vary by age, sex, height, and fitness but follow fixed relationships.
Formula to Calculate Expiratory Reserve Volume
The vital capacity equation is VC = TV + IRV + ERV.
To calculate expiratory reserve volume:
ERV=
Solved Example: ERV Calculation
For VC = 4900 ml, TV = 500 ml, IRV = 3300 ml:
ERV=4900−500−3300=1100 ml
This fits normal ERV range, confirming physiological accuracy.
| Parameter | Given Value (ml) | Typical Adult Range (ml) |
|---|---|---|
| VC | 4900 | 4000-5000 |
| TV | 500 | 500 |
| IRV | 3300 | 2500-3300 |
| ERV | 1100 | 1000-1200 |
Clinical and Exam Relevance
Spirometry measures TV, IRV, and ERV to compute VC, aiding diagnosis of obstructive (e.g., asthma) or restrictive (e.g., fibrosis) diseases. For CSIR NET, master these for questions on lung capacities like total lung capacity (TLC = VC + residual volume). Practice similar calculations to score in breathing and gas exchange sections.
