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Lung Volumes, Types of Respiratory Volumes and Capacities
Did you know, psychologists have found that breathing practice is very effective in fighting stress, anxiety and depression. Physiological evidence also has indicated that even a single daily breathing practice significantly reduces blood pressure.
Our emotions also change the way we breathe. Research shows that our breathing pattern can influence the emotion we experience. For example, anxiety leads to rapid breathing.
The process of exchange of O2 from the atmosphere with CO2 produced by the cells is called Breathing.
You might be aware of the term lung capacity and the fact that due to smoking the efficiency of breathing goes down. Have you ever wondered what are the changes that happen to lung capacity due to smoking? To understand this, we need to study the lung volumes and capacities first. So Let’s understand the different types of lung volumes and capacities in this article.
Table of contents
- Lung Volumes
- Lung Capacities
- Spirometer
- Respiratory Volumes
- Respiratory Capacities
- Practice problems
- FAQs
Lung Volumes
They are also known as pulmonary or respiratory volumes. It is the volume of gas lungs can receive, hold or expel under different conditions at a given time during the respiratory breathing cycle.
Lung Capacities or Pulmonary Capacities
They are a combination of two or more pulmonary volumes. They are obtained by the addition of different lung volumes.
The average total lung capacity of a human male is around 6 litres of air. Lung volume measurement is an important part of the pulmonary function test.
Spirometer
The amount of air the lungs can hold, and also the amount of air that is breathed in and out, is measured by several lung volumes and capacities. Some of these can be measured by an instrument called a Spirometer. The lung volumes and capacities show changed values in diseases like asthma, and hence it can be used as a diagnostic method.
Types of Respiratory Volumes
Respiratory Volume is defined as the quantity of air which our lungs can receive, hold or expel under different conditions. It is of the following types:
Tidal Volume (TV)
The volume of air that is inspired or expired during a normal breathing is known as tidal volume. Its value is approximately 500 mL. Value of tidal volume is considered as the lowest among all types of respiratory volumes.
In normal breathing 350 mL normally enters the lungs. It is considered as the alveolar volume. Dead air space includes the air present in the respiratory passages. It is about 150 mL. So tidal volume is considered as the 350 mL alveolar volume plus the dead space volume.
Volume of air breathed per minute is calculated as follows:
500 mL x 12 breaths to 500 mL x 16 breaths
= 6000 to 8000 mL
Inspiratory Reserve Volume (IRV)
It is the additional or extra volume of air a person can inspire by forceful inspiration. This volume ranges from 2500 ml to 3000 mL of air.
Expiratory Reserve Volume (ERV)
It is the additional or extra volume of air a person can expire by forceful expiration. This volume ranges from 1000 mL to 1100 mL.
Residual Volume (RV)
It is the volume of air which remains in the lungs after the forceful expiration. It is about 1100 mL to 1200 mL.
Summary of Lung Volumes
Types of Respiratory or Lung Capacities
Lung Capacity is the sum of two or more respiratory volumes. It is of the following types.
Inspiratory Capacity (IC)
It is considered as the total volume of air that can be inspired after normal expiration. It includes Tidal Volume and Inspiratory Reserve Volume.
IC = TV + IRV
= 500 + 2500 to 3000 mL
= 3000 - 3500 mL
Expiratory Capacity (EC)
It is the total volume of air that a person can expire, after a normal inspiration. It includes Tidal Volume and Expiratory Reserve Volume.
EC = TV + ERV
= 500 + 1000 to 1100 mL
= 1500 - 1600 mL
Functional Residual Capacity (FRC)
It is considered as the volume of air that remains in lungs after normal expiration. It includes Expiratory Reserve Volume and Residual Volume.
FRC = ERV + RV
= 1000 to 1100 + 1100 to 1200
= 2200 - 2300 mL
Vital Capacity (VC)
It is the maximum volume of air that can be breathed in after forced expiration. It includes Expiratory Reserve Volume, Tidal Volume and Inspiratory Reserve Volume.
VC = ERV + TV + IRV
= 1000 to 1100 + 500 + 2500 to 3000
= 4000 - 4500 mL
Total Lung Capacity (TLC)
It is the total volume of air present in lungs after forced inspiration. It includes Residual Volume, Expiratory Reserve Volume, Tidal volume and Inspiratory Reserve Volume.
TLC = RV + ERV + TV + IRV or VC + RV
= 1100 to 1200 + 1000 to 1100 + 500 + 2500 to 3000
= 5200 - 5700 mL
Summary of Lung Capacities
Practice Problems of Lung Volumes
Q1. A patient suffering from a lung disease goes to the pulmonologist. Which of the following instruments pulmonologists have used to measure the Inspiratory Reserve Volume and Expiratory Reserve Volume?
- Sphygmomanometer
- Stethoscope
- Spirometer
- Thermometer
Solution: A spirometer is used to measure the values of several lung volumes and capacities, two of which are the Inspiratory Reserve Volume and the Expiratory Reserve Volume. Hence the correct option is c.
Q2. The maximum volume of air a person can breathe in after forceful exhalation is known as ____________.
- Total Lung Capacity
- Functional Residual Capacity
- Vital Capacity
- Inspiratory Capacity
Solution: Vital Capacity is defined as the maximum volume of air that can be breathed in after a forceful expiration. It can also be defined as the maximum volume of air that can be breathed out after a forceful inspiration. It includes Expiratory Reserve Volume, Tidal Volume and Inspiratory Reserve Volume. VC = ERV + TV + IRV. Hence the correct option is c.
Q3. The volume of air that remains in the lungs after a normal expiration is known as _________.
- Residual Volume
- Tidal Volume
- Inspiratory Capacity
- Functional Residual Capacity
Solution: The volume of air that remains in the lungs after a normal expiration is called functional residual capacity (FRC). It is the sum of Expiratory Reserve Volume (ERV) and Residual Volume (RV). FRC = ERV + RV. It is about 2200 - 2300 mL. Hence the correct option is d.
Q4. How much is the maximum amount of air the lungs can hold after forceful inspiration _________.
- 1200 mL
- 4300 mL
- 500 mL
- 5700 mL
Solution: Total lung capacity (TLC) is the maximum volume of air present in the lungs after or at the end of forceful inspiration. Its value is about 5700 mL. TLC = RV + ERV + TV + IRV or VC + RV. Hence the correct option is d.
Q5. What is the Inspiratory Capacity of a lung?
Answer: Inspiratory Capacity (IC) is the total volume of air that a person can be breathed in after normal expiration. It is the sum of Tidal Volume and Inspiratory Reserve Volume. IC = TV + IRV.
Q6. What is Residual Volume ?
Answer: Residual Volume (RV) is the volume of air that is left in the lungs and the dead space even after forceful exhalation. It is about 1100 mL to 1200 mL.
FAQs of Lung Volumes
Questions1. What is the normal reading of a spirometer?
Answer: 80 percent or more of the predicted value is considered as normal reading in a spirometer.
Questions2. Why FRC changes in smokers?
Answer: Smoking causes the air sacs to lose their elasticity and makes it harder for the body to breathe in oxygen and breathe out carbon dioxide. FRC decreases when there is an alteration in the elastic recoiling of lungs.
Questions3. Write down the name of the person with the greatest lung capacity.
Answer: Three-time Olympic gold medalist, Pete Reed, a British rower, has the largest recorded lung capacity. It is about 11.68 litres.
Questions4. Why do some people have more lung capacities than others?
Answer: There are certain factors that affect lung capacities. They are enlisted below:
Height - Taller people with larger chests have more total lung capacity.
Location - People living at high altitudes normally have larger capacities to compensate for the lower atmospheric pressure.
Lifestyle - Obese people and smokers have lower capacities.
Related Topics to Lung Volumes and Capacities in Biology
NCERT Class 11 Biology Chapters
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