Respiratory Physiology Lecture 6 Part 26: Changes Which Affect the O2-Hb Dissociation Curve

Question 1

How does changes in Hb concentration affect the O₂ dissocation curve?

Answer 1

reduces the oxygen concentration/ capacity (mL/ 100 mL) that has saturated the Hb without necessarily effecting the Hb saturation.

Question 2

O₂ capacity

Answer 2

max amount of O2 that can be combined with Hb

Question 3

Hb saturation

Answer 3

percentage of the available Hb binding sites that have O₂ attached

Question 4

Hb saturation equation

Answer 4

Question 5

Anemia

Answer 5

reduction in the amount of Hb in the blood

Question 6

Polycythemia

Answer 6

Increase of Hb amount in the blood or reduction of blood volume that increases Hb concentration

Question 7

Effect of Carbon Monoxide Poisoning on O₂-Hb Dissociation Curve

Answer 7

• Reduction in O2-Hb binding
• Shift to the left (↓unloading of O2 to tissue); conformational change

Question 8

How does CO reduce unloading of O₂ to the peripheral tissue?

Answer 8

Displace some of the O₂ bound to Hb so much less concentration. When CO attaches to the Hb it causes a conformational change in the Hb that can keep the few molecules of oxygen tightly bound to the Hb so they cannot be unloaded. If you want to unload oxygen from Hb to reduce the amount of Hb saturation you will need to go to lower PO2 levels at the level of the venous system. So less O2 is delivered to the venous system with CO

Question 9

CO affinity for Hb?

Answer 9

CO has 200x affinity for Hb over O₂