21.3B Pulmonary Volumes

Question 1

Lung function may be assessed with a spirometer.

• What are the three pulmonary volumes measured?
• A fourth pulmonary volume not assessed by spirometry - what is it?

Answer 1

the tidal volume (TV)

the inspiratory reserve volume (IRV)

the expiratory reserve volume (ERV)

A fourth pulmonary volume not assessed by spirometry is the residual volume (RV)

Question 2

1. •amount of air inspired or expired during normal quiet ventilation
2. •volume of air that can be forcibly inspired after normal TV inspiration
3. •amount of air that can be forcibly expired after normal tidal expiration
4. •air remaining in lungs after forceful expiration

Match: IRV, RV, ERV, TV

Answer 2

• TV – amount of air inspired or expired during normal quiet ventilation
• IRV – volume of air that can be forcibly inspired after normal TV inspiration
• ERV – amount of air that can be forcibly expired after normal tidal expiration
• RV – air remaining in lungs after forceful expiration

Question 3

What is Tidal volume (TV? what is the average volume in healthy adults?

Answer 3

• TV – amount of air inspired or expired during normal quiet ventilation
• about 500 ml in healthy adults

Question 4

Inspiratory reserve volume (IRV) – what is it?

What is the average volume?

Answer 4

–Inspiratory reserve volume (IRV) – volume of air that can be forcibly inspired after normal TV inspiration; IRV averages 2.1–3.3L depending on gender and body size

Question 5

Expiratory reserve volume (ERV)

what is it

average amount

Answer 5

–Expiratory reserve volume (ERV) – essentially opposite of IRV; amount of air that can be forcibly expired after normal tidal expiration

§ERV averages 700–1200 ml of air; much less than IRV

§Difference between IRV and ERV is about 1400–2100 ml; even with most forceful expiration, some air remains in lungs (residual volume (RV))

§RV is due to intrapleural pressure, and outward recoil of chest wall; keeps lungs slightly inflated

Question 6

Pulmonary volumes may be combined to yield _______including what?

Answer 6

Pulmonary Capacities - Pulmonary volumes may be combined to yield pulmonary capacities, including

the inspiratory capacity,

vital capacity,

functional residual capacity,

and total lung capacity.

Question 7

• Total lung capacity (TLC) is what?
• What does it represent?
• How do you calculate it?

Answer 7

–Total lung capacity (TLC) – sum of all pulmonary volumes; represents total amount of exchangeable and nonexchangeable air in lungs: (IRV + TV + ERV + RV = TLC)

Question 8

Vital capacity = __________

A. tidal volume + inspiratory reserve volume + expiratory reserve volume

B. inspiratory reserve volume + residual volume

C. inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume

D. expiratory reserve volume + residual volume

Answer 8

Answer: A. tidal volume + inspiratory reserve volume + expiratory reserve volume

Vital capacity – calculated as total amount of exchangeable air, or total amount of air that can move in and out of lungs: (TV + IRV + ERV = vital capacity)

Question 9

Inspiratory capacity

Answer 9

–Inspiratory capacity – total amount of air that person can inspire after tidal volume:

(TV + IRV = inspiratory capacity)

Question 10

Functional residual volume

Answer 10

–Functional residual volume – amount of air that is normally left in lungs after tidal expiration: (ERV + RV = functional residual volume)