Question

The vital capacity, tidal volume, and inspiratory reserve volume of the lungs of a healthy individual are 4600 milliliters (mL), 500 mL, and 2500 mL, respectively. The expiratory reserve volume of the lungs of this individual is mL. (Round off to the nearest integer).

Hint:

Vital capacity is tidal volume plus inspiratory reserve volume plus expiratory reserve volume. Just subtract the two known volumes from vital capacity.

Answer 1

Correct Answer: 1600

Step 1: Recall how the lung volumes fit together.
Vital capacity (VC) is the total air a person can move in a single breath, from a full inhale to a full exhale. It is made up of three smaller volumes added together: the tidal volume (TV, the air moved in normal quiet breathing), the inspiratory reserve volume (IRV, the extra air you can pull in beyond a normal breath), and the expiratory reserve volume (ERV, the extra air you can push out beyond a normal breath).
\[ VC = TV + IRV + ERV \]

Step 2: Fill in the known values.
\[ VC = 4600 \text{ mL}, \quad TV = 500 \text{ mL}, \quad IRV = 2500 \text{ mL} \]

Step 3: Solve for the expiratory reserve volume.
\[ ERV = VC - TV - IRV \]
\[ ERV = 4600 - 500 - 2500 \]
\[ ERV = 4600 - 3000 = 1600 \text{ mL} \]

Step 4: Sanity check.
Adding the three parts back gives \(500 + 2500 + 1600 = 4600\) mL, which matches the given vital capacity, so the value is consistent.

Final Answer:
The expiratory reserve volume is 1600 mL. \[ \boxed{ERV = 1600 \text{ mL}} \]