AQA · A-Level · Physical Education
Course version: 7582 · Version from Sept 2016
Respiratory system: Expiratory reserve volume.
Expiratory reserve volume (ERV) is the extra volume of air a person can force out of the lungs after a normal, quiet expiration has finished.
Checked against the AQA 7582 specification (opens in a new tab) on .
- Point 3 of 17
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Expiratory reserve volume (ERV) is the extra volume of air a person can force out of the lungs after a normal, quiet expiration has finished. It is measured with a spirometer: the subject breathes normally, then exhales as fully and forcefully as possible, and the volume expelled beyond the tidal volume is the ERV. Typical resting values are around 1.0–1.2 dm³ (litres) in healthy young adults, and it is reduced in obstructive and restrictive conditions that limit full exhalation. ERV is one of the four primary lung volumes, alongside tidal volume, inspiratory reserve volume and residual volume, and it contributes to functional residual capacity and vital capacity.
What earns the marks
- ERV is the additional volume of air that can be forcibly exhaled after the end of a normal tidal expiration.
- Typical resting values are approximately 1.0–1.2 dm³ in healthy young adults.
- ERV is reduced when expiration is obstructed or when lung volumes are restricted.
- ERV is a primary lung volume and contributes to functional residual capacity and vital capacity.
Common mistakes and how to put them right
Confusing ERV with tidal volume.
Put it right: Tidal volume is the air moved in one quiet breath, whereas ERV is the extra air forcibly exhaled after that quiet breath.
Confusing ERV with residual volume.
Put it right: Residual volume is the air that cannot be exhaled at all, whereas ERV can be exhaled with effort.
Thinking ERV is the total air exhaled in one maximal breath.
Put it right: That total is the vital capacity, which includes tidal volume, inspiratory reserve volume and ERV.
Exam tips
- Learn the definition as 'extra air forcibly exhaled after a normal expiration' and use those exact functional words in your answer.
- Link ERV to a spirometer trace: identify the section below the tidal volume baseline that represents the forced extra exhalation.
- Practise comparing ERV with the other lung volumes so you can eliminate distractors quickly in multiple-choice questions.
Try the lesson
The start of the Respiratory system: Expiratory reserve volume. lesson, made from checked teaching notes for this specification point.
Have a go first
Which lung volume is defined as the additional volume of air that can be breathed out after a normal resting expiration?
Listen
Expiratory reserve volume (ERV) is the extra volume of air a person can force out of the lungs after a normal, quiet expiration has finished. It is measured with a spirometer: the subject breathes normally, then exhales as fully and forcefully as possible, and the volume expelled beyond the tidal volume is the ERV. Typical resting values are around 1.0–1.2 dm³ (litres) in healthy young adults, and it is reduced in obstructive and restrictive conditions that limit full exhalation. ERV is one of the four primary lung volumes, alongside tidal volume, inspiratory reserve volume and residual volume, and it contributes to functional residual capacity and vital capacity. A strong answer earns marks for these points. ERV is the additional volume of air that can be forcibly exhaled after the end of a normal tidal expiration. Typical resting values are approximately 1.0–1.2 dm³ in healthy young adults. ERV is reduced when expiration is obstructed or when lung volumes are restricted. ERV is a primary lung volume and contributes to functional residual capacity and vital capacity. Exam tip: Learn the definition as 'extra air forcibly exhaled after a normal expiration' and use those exact functional words in your answer.
Key words
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Expiratory reserve volume
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Spirometry and measurement
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Respiratory adaptations and limitations
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Lung volumes and capacities
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See every definition
- Expiratory reserve volume
- The extra volume of air a person can force out of the lungs after a normal, quiet expiration has finished.
- Spirometry and measurement
- A spirometer is used: the subject breathes normally, then exhales as fully and forcefully as possible, and the volume expelled beyond the tidal volume is the ERV.
- Respiratory adaptations and limitations
- Typical resting values are around 1.0–1.2 dm³ in healthy young adults, and it is reduced in obstructive and restrictive conditions that limit full exhalation.
- Lung volumes and capacities
- One of the four primary lung volumes, alongside tidal volume, inspiratory reserve volume and residual volume, contributing to functional residual capacity and vital capacity.
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