54: Oxygen Transport Flashcards
Solubility of Oxygen
0.003 ml O2 per 100 ml of plasma
[02] dissolved
PO2 (100) x 0.003
Blood oxygen content is increased by which oxygen carrier molecule?
Hemoglobin
Hemoglobin
tetramer
each monomer has heme group (porphyrin ring with Fe & polypeptide globin)
O2 saturation
25, 50, 75, or 100%
Saturation
fraction of hemoglobin binding sites that are currently occupied of O2 (%)
1 g of hemoglobin
can bind 1.36 ml O2
Oxygen content
1.36 x 15 = 20.4
Saturation Curve
Sigmoid binding curve
Hill coefficient of 2.8, amount of agonist binding to binding site
Why is Hill coefficient of saturation curve not 4?
B/c there’s not complete cooperativity
Cooperativity
once one O2 bound to hemoglobin, it’s easier for next one to bind
binding site affinity increased for agonist
Hemoglobin relaxed state
high affinity for O2
Hemoglobin tense state
low affinity for O2
Percent Saturation equatioin
100 x (PO2)^2.8 divided by (P50)^2.8 + (PO2)^2.8
P50: 50% of binding
P50 of Oxygen
27mm Hg, 50% Hb binding sites are full
low P50: high affinity
high P50: low affinity