High-Yield Concepts in Pulmonary Physiology

Question 1

Areas of gas exchange in the respiratory tract

Answer 1

Respiratory bronchiole
Alveolar ducts
Alveoli

Question 2

4 basic lung volumes

Answer 2

Inspiratory Reserve Volume (IRV)
Tidal Volume (TV)
Expiratory Reserve Volume (ERV)
Residual Volume (RV)

Question 3

Amount of air inhaled/exhaled with each normal breath

Answer 3

TV (~0.5 L)

Question 4

Amount of air remaining in the lungs after full exhalation

Answer 4

RV (maintains oxygenation between breaths)

Question 5

Maximum amount of air that one can inhale/exhale

Answer 5

Vital Capacity (IRV + TV + ERV)

Question 6

Anatomic dead space volume

Answer 6

Area with no gas exchange from nose to terminal bronchiole (~150 mL)

Question 7

Physiologic dead space volume

Answer 7

Anatomic dead space volume + alveolar dead space volume

Question 8

Alveolar ventilation per minute

Answer 8

Respiratory Rate x (TV - Physiologic Dead Space Volume)

Question 9

Minute respiratory volume

Answer 9

TV + RR

Question 10

Stimulates central chemoreceptors in the medulla

Answer 10

Carbon dioxide (as CSF H+)

Question 11

Lung zones

Answer 11

Zone 1 (no blood flow)
Zone 2 (intermittent blood flow)
Zone 3 (continuous blood flow)

Question 12

Increase in the following factors would cause shift to the right of the O2-Hgb dissociation curve (unloading of O2 from Hgb)

Answer 12

Mnemonic: CADET face RIGHT:

CO2, Acidosis, 2,3-DPG, Exercise, Temperature

Question 13

Increase in the following factors would cause shift to the left of the O2-Hgb dissociation curve (increased binding of O2 to Hgb)

Answer 13

Carbon monoxide, fetal hemoglobin

Question 14

Percentage of blood that gives up oxygen as it passes through the tissue capillaries

Answer 14

Utilization coefficient (25% at rest, 75-85% during exercise)

Question 15

Central control of inspiration; sends inspiratory ramp signals

Answer 15

Dorsal respiratory group (DRG) of the medulla

Question 16

Central control of both inspiration and expiration; sends overdrive mechanism in exercise

Answer 16

Ventral respiratory group (VRG) of the medulla

Question 17

Limits inspiration and increases respiratory rate

Answer 17

Pneumotaxic center of the pons

Question 18

Stimulates inspiration and decreases respiratory rate

Answer 18

Apneustic center of the pons

Question 19

Receptors in ventral medulla; stimulated by CSF H+ from blood CO2; adapts within 1-2 days

Answer 19

Central chemoreceptors (made up of DRG and VRG)

Question 20

Receptors in carotid bodies (CN IX) and aortic bodies (CN X); activated when PO2

Answer 20

Peripheral chemoreceptors