Oxyhemoglobin Dissociation Curve Flashcards Preview

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1

Which graphical representation tells us the tendency of hemoglobin to bind oxygen?

Oxyhemoglobin dissociation curve

2

The PaO2 where hgb is 50% saturated by oxygen is called:

P50

3

A lower P50 reflects:

A. a left shift

B. a right shift

A. a left shift

4

A higher P50 reflects:

A. a left shift

B. a right shift

B. a right shift

5

Maximum 02 loading occurs at a PaO2 of:

100 mmHg

6

A PaO2 above 100 mmHg:

A. Improve 02 loading

B. increase the amount of 02 that is dissolved in the plasma.

B. increase the amount of 02 that is dissolved in the plasma.

(Maximum 02 loading occurs at a PaO2 of - 100 mmHg. A PaO2 above this cannot improve 02 loading, but it does increase the amount of 02 that is dissolved in the plasma)

7

Many of the conditions that shift the curve are related to which physiologic process?

Metabolic rate

8

True or False

Tissues with a high metabolic rate consume more 02 and produce more CO2, hydrogen ions, and heat

True

Tissues with a high metabolic rate consume more 02 and produce more CO2, hydrogen ions, and heat

9

Tissues with a high metabolic rate consume more 02 and produce more CO2, hydrogen ions, and heat. . This causes a:

A. Left shift

B. Right shift

B. Right shift

10

Right shift (right= rise) is associated with an increase in which four components?

 Temp

2,3-DPG

CO2

[H+]

11

Left shift (left= lower) is associated with a decrease in which four components?

Temp

2,3-DPG

CO2

[H+]

12

Most hemoglobinopathies (e.g. HgbMet, HgbCO, Hgb F) cause a

A. left shift

B. Right shift

A. left shift

13

CO2 and hydrogen ions cause a conformational change in the hemoglobin molecule; this facilitates the release of

oxygen

14

Said another way, which two chemical entities cause Hgb to release oxygen?

CO2 and H+

15

CO2 and hydrogen ions cause a conformational change in the hemoglobin molecule; this facilitates the release of oxygen. Said another way, CO2 and H+ cause Hgb to release oxygen.

This phenomenon is known as:

Bohr Effect

16

Which molecule is produced during RBC glycolysis (the Rapoport-Leubering pathway).

2,3-DPG

17

2,3-DPG maintains the OxyHgb curve in a

A. slightly left-shifted position at all times

B. slightly right-shifted position at all times

B. slightly right-shifted position at all times

18

Which increases 2,3-DPG production?

A. Decreased CO2

B. Hypoxia

B. Hypoxia

19

Hypoxia increases 2,3-DPG production. This facilitates

A. O2 affinity

B. O2 offloading

B. O2 offloading

20

2,3 DPG is an important compensation mechanism during:

A. Elevated Hgb/Hct

B. Chronic anemia

Chronic anemia

21

In banked blood, the concentration of 2,3-DPG

A. Falls

B. Increases

A. Falls

22

In banked blood, the concentration of 2,3-DPG falls. This shifts the oxyhemoglobin dissociation curve to the

A. Left

B. Right

A. Left

23

In banked blood, the concentration of 2,3-DPG falls. This shifts the oxyhemoglobin dissociation curve to the left and

A. reduces the amount of 02 available at the tissue level

B. increases the amount of 02 available at the tissue level

A. reduces the amount of 02 available at the tissue level

24

What's the P50 of Hgb F?

19 mmHg

 

25

Hgb F has a

A. left shift

B. right shift

A. left shift

26

Which explains why Hgb F has a left shift?

Hgb F doesn't respond to 2,3-DPG

27

References:

 

Hall. Guyton and Hall Textbook of Medical Physiology 11th ed. 2011. p. 500-501. Nagelhout. Nurse Anesthesia. 6th  ed. 2018.  p.. 575-576