Lecture 30: Gas transport

Question 1

Describe the shape of the oxyhemoglobin dissociation curve. Why is it shaped like that?

Answer 1

sigmoidally shaped. originally starts out in tense conformation, once Poxygen increases, then it switches to relaxed conformation which has higher oxygen affinity

Question 2

What factors affect the oxyhemoglobin dissociation curve, and how do they change it?

Answer 2

pH - shift right, less affinity. metabolically active, decrease pH, want to unload more O2
CO2 - shift right, less affinity, same reasoning
Temperature - shift right, less affinity, metabolically active cells release heat
2,3-BPG - byproduct of anaebolic metabolism of RBC, will cause decreased affinity
HbF - increased affinity, able to load oxygen (high saturation) at pressures typical at the placenta

Question 3

How is carbon dioxide transported in the arteries vs in the veins

Answer 3

Mainly in bicarbonate ions, although more is transported attached to Hb in the veins. some is transported dissolved in the plasma

Question 4

What is the Haldane effect?

Answer 4

Hb has greater affinity for CO2 when unloaded of O2. therefore when Hb unloads O2 at the tissues, more likely to pick up CO2, and more likely to unload CO2 at the lungs

Question 5

What five factors affect CO2 carrying capacity?

Answer 5

PCO2 - increase causes increase in carrying capacity since more HCO3-
plasma protein concentration - more pH buffering with more concentration, drives HCO3- produciton
plasma pH - higher pH means HCO3- increases
Hb concentration - increase= increases carrying capacity, more carbamino hemoglobin, more pH buffering
PO2 - decreased O2 means higher carrying capacity, due to Haldane effect