Question

Arrange the following in the order of increasing volume 1\. Tidal volume 2\. Residual volume 3\. Expiratory reserve volume 4\. Inspiratory reserve volume (a) \(1<2<3<4\) (b) \(1<4<3<2\) (c) \(1<3<2<4\) (d) \(1<4<2<3\)

Short answer

The correct order of increasing volume is: tidal volume < expiratory reserve volume = residual volume < inspiratory reserve volume, which is presented in option (c).

Step-by-step solution

Understand the Definitions

Tidal volume is the volume of air breathed in or out during a normal breath, which is roughly 500 ml. Residual volume is the volume of air that remains in the lungs even after a maximal expiration and is typically around 1100-1200 ml. Expiratory reserve volume is the additional amount of air that can be expired from the lungs by determined effort after normal expiration and approximately equals to 1000-1200 ml. Finally, the inspiratory reserve volume is the maximum amount of air that can be inhaled over the level of normal tidal inspiration, typically 1900-3300 ml.

Compare the Measurements

By comparing these measurements, it is clear that the volumes are increasing in the following order: tidal volume < expiratory reserve volume = residual volume < inspiratory reserve volume.

Match the Answer

The ordering presented in the previous step corresponds to the order presented in option (c). Therefore, the correct answer is (c).

Key concepts

Tidal Volume

Tidal Volume is an essential concept as it refers to the amount of air you breathe in or out during a normal, relaxed breath. Imagine you take a slow, gentle inhale while sitting relaxed; the air entering your lungs is what's defined as your Tidal Volume.
Your average Tidal Volume is about 500 milliliters.

• This volume indicates the normal and rhythmic air exchange while at rest.
• It sets the baseline for understanding more about our lung capacities as it's the most basic measure of breathing.

By understanding Tidal Volume, we lay the foundation for exploring how our lungs handle larger volumes of air that are influenced by our body's needs or efforts.

Residual Volume

Residual Volume is quite intriguing because it refers to the air that always remains in our lungs, even after we exhale as hard as we can. This remaining air prevents our lungs from collapsing and ensures that the lungs are always a bit inflated.
Typically, Residual Volume is around 1100 to 1200 milliliters.

• This volume is crucial for maintaining consistent and efficient gas exchange.
• It acts as a buffer so our bodies can still get enough oxygen even when we're not actively breathing in new air.

Grasping this concept teaches us why it's physically impossible to "completely" empty our lungs.

Expiratory Reserve Volume

The Expiratory Reserve Volume (ERV) is the additional air you can forcefully exhale after a normal exhalation. When you breathe out normally, you still have some air in your lungs that you could push out further if needed. That extra bit of air is the ERV.
This volume usually measures about 1000 to 1200 milliliters.

• It reflects our lung's potential to expel more air when required, like during exercise or certain physical activities.
• Having a good ERV can indicate healthier and stronger lung function.

Understanding ERV helps us appreciate the lungs' flexibility and ability to support various respiratory demands.

Inspiratory Reserve Volume

The Inspiratory Reserve Volume is quite fascinating as it represents the extra air you can inhale beyond a normal inhalation. Imagine taking a deep breath, even deeper than usual, when ready to blow birthday candles; that's tapping into your Inspiratory Reserve Volume.
Typically, this volume can range between 1900 and 3300 milliliters.

• It indicates our lungs' reserve capacity to bring in more air when our body demands more oxygen.
• Having a higher Inspiratory Reserve Volume suggests greater lung capacity and health.

This concept highlights the potential of our lungs to adjust to increased oxygen requirements, like during intense physical activities.