Uptake of O2 across the Alveolar-Capillary Membrane (PK4)

Question 1

What is uptake of gas into the blood dependent on?

Answer 1

• Solubility
• Chemical combination

Question 2

How long is blood in the alveolar capillaries before it leaves?

Answer 2

0.75s

Question 3

In what 2 ways can a gas be limited?

Answer 3

• Diffusion limited (does not reach equilibrium in the 0.75s)
• Perfusion limited (reaches equilibrium very quickly and has lots of the 75s left)

Question 4

Is oxygen diffusion or perfusion limited in a healthy person?

Answer 4

Perfusion limited

Question 5

What is diffusion reserve time?

Answer 5

Time spent when gas has reached equilibrium and is no longer diffusing

Question 6

Why would someone with abnormal lungs become hypoxic upon exercise, with relation to diffusion reserve time?

Answer 6

• Abnormality reduces diffusion reserve time
• Cardiac output increases upon exercise, reducing 0.75s blood is in capillaries
• Oxygen cant equilibrate in reduced time, so person is hypoxic