Question

Vital Capacity of lungs is
a. IRV+ERV
b. IRV+ERV+TV-RV
c. IRV+ERV+TV+RV
d. IRV+ERV+TV

Answer 1

Hint: According to the work they perform, different animals have differences in their lung capacities. For example- animals that run very fast, like cheetahs, have much more lung capacity than humans. Also animals with huge body mass such as elephants also have high lung capacity.

Complete answer:
Breathing has two main steps - inspiration and expiration. During inspiration/inhalation, air is drawn into the lungs from the atmosphere, and during expiration/exhalation, air is released out from the alveoli to the atmosphere. On an average, human beings have a breathing rate of 12-16 times per minute. The volumes of air involved in the activity of breathing (at different phases of the respiration cycle) are termed as respiratory volumes. They are measured by the technique known as spirometry.

Volume of air in the lungs can be divided into four parts named as Tidal Volume (TV), Inspiratory Reserve Volume (IRV), Expiratory Reserve Volume (ERV) and Residual Volume (RV).

> Tidal Volume (TV) – It is the amount of air inhaled or exhaled in a normal respiration. On an average, it is 500ml.
> Inspiratory Reserve Volume (IRV) – It is the amount of air that can be inspired beyond the normal amount inspired. It can be achieved by inspiring forcefully. On an average, it can be 2500-3000ml.
> Expiratory Reserve Volume (ERV) – Opposite to IRV, it is the amount of air that can be forcefully exhaled beyond the normal exhalation. On an average, it is 1000-1100ml.
> Residual Volume (RV) – Lungs cannot remain empty at any point of time. RV is the amount of air that remains in the lungs after a forceful expiration is done. On an average, it is 1100-1200ml.

We can increase these volumes of inspiration and expiration with the help of our muscle present in the abdomen.
When two or more volumes are measured together, it is called Lung Capacity. There are five types of lung capacities. These are Inspiratory Capacity (IC), Expiratory Capacity (EC), Functional Residual Capacity (FRC), Vital Capacity (VC) and Total Lung Capacity (TLC).

Vital Capacity is the maximum amount of air a person can inhale after a forceful exhalation or the maximum amount of air a person can exhale after a forceful inhalation. It includes Expiratory Reserve Volume (ERV), Tidal Volume (TV) and Inspiratory Reserve Volume (IRV).

Hence, the correct answer is option (D).

Note: On an average, vital Capacity of an adult is 3 to 5 litres. Its volume depends upon the factors such as age, sex, mass and height of the person. Sometimes, environmental factors also play an important role in the volume of Vital Capacity of an individual.