Lecture 16 - Oxygen/Hb Dissociation Curve

Question 1

0 partial pressure of O2 = 0% Hb saturation and as you increase the partial pressure of O2 in the blood, the % Hb saturation rises

Question 2

what happens when 1 molecule of O2 binds to 1 heme molecule on Hb

Answer 2

Hb changes its shape (3-dimensional shape), making the other heme molecules on Hb (the other 3 that don’t yet have oxygen attached) more accessible and easier to bind} this keeps happening as more O2 molecules bind to the heme groups

Question 3

As O2 binds to Hb, the Hb affinity for O2 increases or decrease?

Answer 3

increases

Question 4

what happens when partial pressure of O2 is high

Answer 4

it wants to bind hemoglobin (at the alveoli/lung = red area in diagram)

Question 5

what happens when partial pressure of O2 is low,

Answer 5

it wants to get rid of oxygen (at the tissues/capillaries = blue area in diagram)

Question 6

what is the PAO2 (partial pressure of oxygen in alveoli) at sea level

Answer 6

100mmHg

Question 7

what is the PAO2 (partial pressure of oxygen in blood) at sea level

Answer 7

100mmhg

Question 8

what is the %Hb saturation at 100mmHg

Answer 8

97-100%

Question 9

thus even if we had more oxygen available there is no place for it to bind since we’re already fully saturated

Question 10

As we increase the partial pressure of O2 in the blood, the dissolved O2 doesn’t really increase} why?

Answer 10

because O2 has a low solubility coefficient so you can’t drive more O2 in blood by increasing pressure because the Hb is already saturated

Question 11

Things That Can Shift the O2/Hb Dissociation Curve

Answer 11

Increase in CO2
Increase in H+ (acid content)
Increase in temp.
(the three things above happen during exercise)

2,3-Bisphosphoglycerate (happens when you go to altitude)

Question 12

What Happens When You Shift The disassociation Curve to The Right?

Answer 12

hemoglobin has a lower affinity for oxygen at any given partial pressure of oxygen