Lecture 3: Gas Exchange and Transport

Question 1

what is the respiratory quotient and what is the formula

Answer 1

• metabolic activity of the body in steady state conditions

- Co2 produced / O2 absorbed

Question 2

what is the respiratory quotient at rest

Answer 2

0.8

Question 3

what is the respiratory quotient for fat metabolism

Answer 3

0.7

Question 4

what is the respiratory quotient for carbohydrate metabolism

Answer 4

1.0

Question 5

what is Fick’s Law

Answer 5

rate of gas transfer is:

• proportional to tissue area
• difference in partial pressure of the gas
• inversely proportional to tissue thickness

Question 6

what does a low V/Q ratio result in

Answer 6

• decreased arterial pO2

- increased arterial pCO2

Question 7

what does a high V/Q ratio result in

Answer 7

• increased arterial pO2

- decreased arterial pCO2

Question 8

what is type 2 respiratory failure

Answer 8

• pure underventilation

- increased PaCO2 and proportionate fall in PaO2

Question 9

what is type 1 respiratory failure

Answer 9

• disturbance in V/Q matching

- fall in PaO2 with no change to PaCO2

Question 10

what is the partial pressure of oxygen in the air

Answer 10

21 kPa

Question 11

what is the alveolar gas equation

Answer 11

PAO2 = PIO2 - (PaCO2/0.8)

Question 12

what is the normal alveolar arterial gradient in healthy young adults

Answer 12

< 2 kPa