lecture 11 - gas transport

Question 1

What is the shape of the oxyhaemoglobin dissociation curve?

Answer 1

Sigmoidal

Question 2

What is the typical O2 saturation of arterial blood?

Answer 2

98%

Question 3

What is O2 capacity?

Answer 3

The maximal amount of oxygen that haemoglobin can carry when 100% saturated.

Question 4

What are the factors that result in a change in O2 affinity

Answer 4

PCO2, [H+], temperature, DPG

Question 5

What is a leftward shift in O2 affinity?

Answer 5

Increased loading of PO2 in the lungs

Question 6

What is a rightward shift in O2 affinity?

Answer 6

More unloading of O2 at a given PO2 in tissues

Question 7

What factors will cause a leftward shift to the O2 dissociation curve?

Answer 7

Decreased PCO2, Decreased acidity (H+), Decreased temperature, decreased BPG conc.

Question 8

What changes occur in exercising muscle to increase O2 unloading?

Answer 8

Acid production, CO2 production, increased temperature, DPG production

Question 9

What is 2,3-DPG?

Answer 9

A by-product of glycolysis that shifts the oxygen dissociation curve to the right

Question 10

How is the oxygen saturation curve affected by anaemia?

Answer 10

It is not - the ability of Hb to bind oxygen is the same, it is just that there is less Hb available

Question 11

How is the oxygen saturation curve affected by Carbon monoxide?

Answer 11

Carbon Monoxide binds with Hb more easily than O2, resulting in a reduced amount of Hb that can carry O2. This shifts the O2 binding curve to the left - making it more difficult to unload O2 to tissues

Question 12

What enzyme catalyses the reaction of CO2 to bicarbonate in cells?

Answer 12

Carbonic anhydrase

Question 13

What is the Bohr Effect?

Answer 13

A right shift in the oxygen dissociation curve due to increase CO2, H+, temperature or DPG