Resp - Ventilation

Question 1

Henry’s law

Answer 1

amt of a gas that dissolves into a fluid is proportional to:
solubility
temp
partial P

Question 2

Dalton’s law

Answer 2

total P of a gas mixture is equal to sum of Ps that each gas exerts independently
(Patm = PO2 + PN2…)

Question 3

effects of humidity on O2

Answer 3

dilute PP

no change in O2, just partial P

Question 4

total ventilation

Answer 4

VE = VT x f
(total ventilation = tidal volume x respiratory rate)
VT more important

Question 5

types of dead space

Answer 5

anatomical (conducting airways)
alveolar (in unhealthy)
physiological = anatomical + alveolar
(healthy physiological = anatomical)

Question 6

alveolar ventilation

Answer 6

VA = (*VT - VD) x f
alveolar ventilation = (tidal V - anatomic dead space) x resp rate
VT most imporant

Question 7

alternate equation to VA

Answer 7

VA = VECO2 x 0.863/ PACO2

show how effecctively reducing CO2

Question 8

CO2 alveolar P eq

Answer 8

PACO2 = VECO2 x 0.863/VA

PACO2 can be substituted by PaCO2

Question 9

hypo/hyperventilation and CO2

Answer 9

hyperventilate –> PaCO2 down

hypoventilate –> PaCO2 up

Question 10

conclusions drawn from high PaCO2

Answer 10

not enough ventilation (CNS, muscle weak)

too much ventilation ending up as dead space (COPD, rapid shallow breaths)

Question 11

alveolar gas equation

Answer 11

PAO2 = PIO2 - PACO2/R

R usually 0.8

Question 12

respiratory quotient

Answer 12

R
usually 0.8
ratio of VCO2/VO2
CO2 produced/O2 taken up

Question 13

A-a gradient

Answer 13

for healthy person, PAO2 ~ PaO2

diff is A-a gradient

Question 14

reason for A-a gradient

Answer 14

50% due to regional diff in V/Q (high at apex)

50% due to anatomic shunt (broch veins drain into pulm veins)

Question 15

why is PACO2 = PaCO2

Answer 15

high diffusibility (very soluble)