Deck 47: Gas Exchange in the Lung

Question 1

At b od y tem pe ra tur e, th e v ap or pre ss ur e o f w ate r is

A) 760 mm Hg
B) 713 mm Hg
C) 600 mm Hg
D) 160 mm Hg
E) 47 mm Hg

Answer 1

E

Question 2

Henry's Law is best described as

A) Q A =
V (V
B) PA = fA (PB - PH₂O)
C) [A] = a P
D) Q A = QCO₂ (PB - PH₂O) / PACO₂
E) PAO₂ = PIO₂ - PACO₂/R + fIO₂ PACO₂ [(1-R)/R]

Answer 2

C

Question 3

If glucose is the only fuel used for energy supply, the respiratory quotient would be

A) 1.0
B) 0.7
C) 0.8
D) 0.83
E) 6

Answer 3

A

Question 4

An ex pir ed tida l vo lum e is 0.5 L a t BT PS . Its vo lum e a t ST PD is

A) 350 mL
B) 605 mL
C) 413 mL
D) 469 mL
E) 289 mL

Question 5

The va po r pr es su re of w ate r at the bo iling po int o f w ate r is

A) 760 mm Hg
B) 47 mm Hg
C) Atm osp heric p ressu re or am bien t pres sure
D) 713 mm Hg
E) Cannot be determined from the information given

Question 6

The respiratory quotient is typically about

A) 1.0
B) 0.8
C) 0.7
D) 200
E) 250

Question 7

The respiratory quotient is the ratio

A) TV / TLC
B) FEV1 / VC
C) D LO₂ / DLCO₂
D) PACO₂ / PAO₂
E) Q CO₂ / Q O₂

Question 8

STPD refers to standard conditions of

A) 0o K, 1 atm and saturated with water vapor
B) 0o K, 1 atm and no w ater vapor
C) 0o C, 1 atm and no water vapor
D) 37o C, 1 atm and no water vapor
E) 37oC, 1 atm and saturated with water vapor

Question 9

Exchange of gas between alveolar air and blood is rapid because

A) The surface area for exchange is large
B) Gasses diffuse incredibly fast
C) The dif fus ion dist an ce is sm all
D) The gradients for diffusion are large
E) Both A and C are true

Question 10

Which has the grea test solubility in water?

A) O 2
B) N 2
C) CO₂
D) CO
E) All of the m hav e the sam e so lubility

Question 11

Ga s m ove m ent is d own its

A) Absolute concentration gradient
B) Partial pressure gradient
C) Total pressure gradient
D) Oncotic pressure gradient
E) Velocity of fluid flow gradient

Question 12

The alv eo lar ve ntila tion eq ua tion is

A) Q A =
V (V
B) PA = fA (PB - PH₂O)
C) [A] = a P
D) Q A = QCO₂ (PB - PH₂O) / PACO₂
E) PAO₂ = PIO₂ - PACO₂/R + fIO₂ PACO₂ [(1-R)/R]

Question 13

The vapor press ure of water

A) Depe nds on the a m bient pressure
B) Depends on the temperature of the water
C) Varies with the composition of the gas phase
D) Is greatest for N 2
E) Is greatest for O 2

Question 14

The ide al g as eq ua tion is

A) PA = fA (PB -47)
B) R = Q CO₂ / Q O₂
C) PV = nRT þ P
D) X A = A A
E) [A] = a P

Question 15

The diffusing capacity has units of

A) cm 2 s-1
B) mL dL -1
C) Pa s
D) M ol s -1 cm -2
E) m L m in-1 mm Hg -1

Question 16

The partial pressure of an ideal gas is

A) The m ole frac tion o f the g as tim es th e tota l press ure
B) T he pre ss ur e o f th e g as pe r m ole
C) T he pre ss ur e o f th e g as pe r m ole cu le
D) The pressure of the gas divided by the partial molar volume
E) The pressure the gas would have if it was at STPD

Question 17

The anatomic dead space is

A) The volu me of gas th at fills the no n-exch angin g airw ays
B) The volume of gas that does not exchange with blood
C) The volume of gas left in the lungs after a forceful expiration
D) Greater than the physiological dead space
E) The volume of gas that doesn't move with ventilation

Question 18

Alveolar gas partial pressures at rest

A) Are relatively constant because the tidal volume is a small fraction of the FRC
B) Vary widely during each breath because fresh air replaces "stale" alveolar air during each brea th
C) Vary widely because the blood squirts through unevenly during each ejection cycle of the heart
D) Ar e th e s am e a s th os e in m ois t tra ch ea l air
E) Are relatively constant because the tidal volume is a small fraction of the TLC

Question 19

The diffusing capacity for O₂ Increases markedly during exercise because

A) O 2 diffuses more quickly when the blood is hot
B) Previously non-perfused areas of the lung become perfused with blood
C) Alveolar ventilation is Increased
D) Pulmonary ventilation is Increased
E) The diffusion distance is shorter

Question 20

A person inspires dry air. The N2 partial pressure in moist tracheal air should be

A) The sam e as in dry inspired air because N2 does not exchange
B) The sam e as in dry inspired air because the water vapor merely Increases the total pressure
C) Less than that in dry inspired air because water vapor dilutes all of the gasses
D) M or e th an tha t in d ry ins pir ed air b ec au se ox yge n is rem ov ed fro m the tra ch ea l air
E) Unaffected by anything because N2 is inert to bodily metabolism