Carriage of gases

Question 1

What is the equation for oxygen in solution?

Answer 1

Oxygen in solution= partial pressure oxygen x solubility

Question 2

Example of calculation for oxygen in solution.

Answer 2

PaO2= 13.3 kPa
solubility= 0.225mlO2
Amount of O2 in solution= 13.3 x 0.225
=3ml/Litre

Question 3

What is the total amount of oxygen in arterial blood?

Answer 3

200ml/Litre
(in example- 3ml/L was in solution so the other 98.5% is carried by Hb)

Question 4

What is oxyhaemaglobin?

Answer 4

This is when oxygen is transported in red blood cells in combination with Hb.

Question 5

What are the features of red blood cells?

Answer 5

-biconcave discs (more SA for uptake of O2)
-no nucleus
-flexible
-contains 280 million Hb molecules

Question 6

What is Haemaglobin (Hb)?

Answer 6

This is a protein composed of 4 subunits with a protein chain and haem group.

Question 7

What are the features of 1 haem group?

Answer 7

These contain an iron atom which can bind to an oxygen molecule.

Question 8

What is deoxyHb?

Answer 8

Hb that has released O2.

Question 9

What happens to Hb when loading or unloading O2?

Answer 9

This causes a change in the shape in Hb.
When O2 binds, changes shape to increase affinity for O2 (easier to attach).

Question 10

What is a carboamino compound?

Answer 10

CO2 binds to amino groups and Hb (carboaminoHb).

Question 11

What is the Haldane effect?

Answer 11

Binding of oxygen to Hb promotes release of CO2 and H+.

Question 12

One method of the Haldane effect?

Answer 12

Binding of O2 to Hb reduces affinity for CO2- offload to lungs.

Question 13

Another method of the Haldane effect?

Answer 13

Increased release H+ pushes equilibrium in direction of CO2 to be released to lungs.