L12 Gas transport by the blood

Question 1

How is O2 carried through the blood

Answer 1

98.5% bound to Hb

remaining dissolved in blood, contributing to PO2

Question 2

How is Co2 carried back to lungs?

Answer 2

1. dissolved CO2 in plasma (minimal)
2. protonated Hb (H+Hb) & HCO3- in plasma that meet up at lung and produce CO2 + H20
3. Hb bound directly to CO2

Question 3

What represents the X & Y axis on the oxygen-haemoglobin saturation curve?

Answer 3

X= PO2

Y= % Saturation Hb i.e. % Hb’s binding sites (4) bound with O2

Question 4

Why is the oxygen-haemoglobin curve sigmoidal?

Answer 4

the affinity of Hb for O2 changes depending on how many O2 molecules are bound.

If none, there is a low affinity. With each addition of O2, Hb increases because more likely to bind at high ambient O2 conc.