Respiratory System

Question 1

Tidal volume (V_T)

Answer 1

500 ml

Amount of air that enters or leaves the lungs in a single respiratory cycle.

Question 2

Expiratory reserve volume (ERV)

Answer 2

1200 ml

Additional volume that can be expired after a passive expiration.

Question 3

Residual volume (RV)

Answer 3

1200 ml

Amount of air in the lung after a maximal expiration. This volume cannot be expired.

Question 4

Functional residual capacity (FRC)

Answer 4

2400 ml

Amount of gas in the lungs at the end of a passive expiration.

Question 5

Inspiratory reserve volume (IRV)

Answer 5

3100 ml

Additional amount of air that can be inhaled after a normal inspiration.

Question 6

Inspiratory capacity (IC)

Answer 6

3600 ml

Maximal volume of gas that can be inspired from FRC.

IC = V_T + IRV

Question 7

Vital capacity (VC)

Answer 7

4800 ml

Maximal volume that can be expired after a maximal inspiration.

Question 8

Total lung capacity (TLC)

Answer 8

6000 ml

Amount of air in the lung after a maximal inspiration.

Question 9

Dead space (V_D)

Answer 9

150 ml

Question 10

Breathing (respiratory) rate (RR)

Answer 10

15 breaths/min

Question 11

Minute ventilation (V_E)

Answer 11

7500 ml/min

The total volume of gas entering the lungs per minute.

V_E = V_T x respiratory rate

There is a dot above V in V_E.

Question 12

Alveolar ventilation (V_A)

Answer 12

4.2 L/min (or 5.25 L/min if RR: 15 breaths/min)

The volume of gas per unit time that reaches the alveoli.

V_A = (V_T - dead space) x respiratory rate

There is a dot above V in V_A.

Question 13

Dead space ventilation (V_D)

Answer 13

The volume of gas per unit time that does not reach respiratory portions, but instead remains in the airways.

V_D = dead space x respiratory rate

There is a dot above V in V_D.

Question 14

Intrapleural pressure and alveolar pressure during inspiration

Answer 14

-6.7 mmHg and -0.7 mmHg

Question 15

Intrapleural pressure and alveolar pressure during expiration

Answer 15

-3.7 mmHg and 0.7 mmHg

Question 16

Intrapleural pressure and alveolar pressure at the end of inspiration

Answer 16

-6.7 mmHg and 0 mmHg

Question 17

Intrapleural pressure and alveolar pressure at the end of expiration

Answer 17

-3.7 mmHg and 0 mmHg

Question 18

Alveolar gases

Answer 18

PO₂: 100 mmHg

PCO₂: 40 mmHg

Question 19

Arterial gases

Answer 19

PO₂: 95 mmHg

PCO₂: 40 mmHg

Question 20

Venous gases

Answer 20

PO₂: 40 mmHg

PCO₂: 46 mmHg

Question 21

[O₂] in blood

Answer 21

Arteries: 200 ml/L

Veins: 150 ml/L

Question 22

[Hemoglobin]

Answer 22

[Hb] in males: 160-170 g/liter
[Hb] in females: 135-145 g/liter

[Hb] in general: 2-2.8 mM or 120-180 g/liter

These are the concentrations of whole hemoglobin (consisting of four monomers).

Question 23

O₂ consumption in resting condition

Answer 23

250 ml/min

Question 24

CO₂ production in resting condition

Answer 24

210 ml/min

Question 25

FEV1/FVC

Answer 25

Forced expiratory volume in 1 sec/full vital capacity > 80%

Question 26

PEFR

Answer 26

Peak expiratory flow rate > 8 L/sec

Question 27

Total area of alveoli

Answer 27

70-90 m²