Lung Volumes

Question 1

What volume is the amt of air that can still be breathed in after normal inspiration?

Answer 1

Inspiratory reserve volume

Question 2

What volume is the amt of air that moves into the lung with each quiet respiration?

Answer 2

Tidal volume

Question 3

What is a normal tidal volume?

Answer 3

500mL

Question 4

What volume is the amt of air that can still be breathed out after normal expiration?

Answer 4

Expiratory reserve volume?

Question 5

What volume is the amt of air in lung after maximal expiration?

Answer 5

Residual volume

Question 6

What lung volume cannot be measured on spirometry?

Answer 6

Residual volume

Question 7

What is the inspiratory reserve volume + the tidal volume?

Answer 7

Inspiratory capacity

Question 8

What is the residual volume + expiratory reserve volume?

Answer 8

Functional residual capacity

Question 9

What is the functional residual capacity (in words)?

Answer 9

The volume of gas in the lungs remaining after normal expiration.

Question 10

What is the TV + IRV + ERV?

Answer 10

Vital capacity

Question 11

What is the vital capacity (in words)?

Answer 11

The maximal volume of gas that can be expired after a maximal inspiration; everything except the residual volume, which can’t be expired. It essentially is the “moveable” capacity of the lung.

Question 12

What is the IRV + TV + ERV + RV?

Answer 12

Total lung capacity - the volume of gas present in lungs after maximal inspiration

Question 13

What is dead space?

Answer 13

Volume of inspired air that does not take part in gas exchange

Question 14

What are the components of dead space?

Answer 14

Anatomic dead space of conducting airways + alveolar dead space.

Question 15

Where is the largest contributor of alveolar dead space?

Answer 15

Apex of the lung

Question 16

What is the formula for dead space?

Answer 16

Vd = Tidal volume X (Arterial CO2-Expired CO2)/Arterial CO2

(taco paco peco paco).

Question 17

What does the formula for dead space mean in words?

Answer 17

Dead space = Normal inspiratory volume * % of arterial CO2 that does not get diffused into the alveolus and expired.

Question 18

What is the minute ventilation? (Ve)

Answer 18

Total volume of gas entering lungs per minute.

Vt * RR

Question 19

What is the alveolar ventilation?

Answer 19

Volume of gas per unit time that reaches alveoli

Va = (Vt-Vd) * RR

Question 20

What is the elastic recoil tendency of the lung?

Answer 20

To collapse inward

Question 21

What is the elastic recoil tendency of the chest wall?

Answer 21

To spring outward

Question 22

What is the point at which the inward pull of the lung is balanced by the outward pull of the chest wall?

Answer 22

Functional residual capacity; this is the volume of gas in lungs after normal expiration.

Question 23

How does system pressure in the lungs compare to atmospheric pressure at the elastic recoil balance point?

Answer 23

They are equal; essentially, when you finish a normal breath, you’re at a “starting” point, or a “balance” point. This ends the airflow out of the lungs (leaving the functional residual capacity - you have to blow harder to get that out, as there is no longer a pressure gradient doing the work for you) and air does not flow in yet until negative pressure is generated by inspiratory forces.

Question 24

What are the determinants of FRC?

Answer 24

Elastic properties of both chest wall and lungs

Question 25

At FRC, what is intrapleural pressure? Why?

Answer 25

Negative. Prevents pneumothorax.

Question 26

What is the compliance of the lung?

Answer 26

“Stretchiness” - change in lung volume for a given change in pressure.

Question 27

How does compliance of the lung change with emphysema and aging?

Answer 27

Increases. More loose and stretchy.

Question 28

How does compliance of the lung change with pulmonary fibrosis, pneumonia, and pulmonary edema?

Answer 28

Decreases. More tight and unstretchy.