Oxygen Transport

Question 1

How much of O2 is dissolved in plasma?

Answer 1

1.5%

Question 2

PaO2 is directly proportional to what?

Answer 2

dissolved O2 in plasma

Question 3

What is the structure of a hemoglobin molecule?

Answer 3

4 heme and 1 globin molecule

Question 4

How many oxygen molecules can bind to a hemoglobin?

Answer 4

4

Question 5

True or False: CO2 binds to the same site that oxygen binds to

Answer 5

False

Question 6

What is critical for O2 binding to globin?

Answer 6

the amino acid sequence

Question 7

Why is fetal hemoglobin so great?

Answer 7

it has a higher affinity to oxygen and can manage some form of hypoxia

Question 8

What causes nitrate poisoning?

Answer 8

Fe(2+) and Fe(3+)

Question 9

What does CO + Hb make?

Answer 9

carboxyHb

Question 10

True or False: CO occupies the same site as O2.

Answer 10

true

Question 11

CO has ___ times more affinity than O2.

Answer 11

200

Question 12

Is O2 binding with heme reversible or irreversible?

Answer 12

reversible

Question 13

What is the law of mass action?

Answer 13

the products formed are proportionate to the reaction

Question 14

What determines % Hb saturation?

Answer 14

PO2

Question 15

What is allosteric (cooperativity)?

Answer 15

when a hemoglobin already has oxygen bound to it, it will attract more oxygen to the area rather than that oxygen going to an empty hemoglobin

Question 16

How many mL of O2 binds with 1 g of Hb?

Answer 16

1.34-1.39

Question 17

What percent saturation is mixed venous blood?

Answer 17

60%

Question 18

What does PvO2 equal normally?

Answer 18

40 mmHg

Question 19

What pressure is 50% saturation at?

Answer 19

25 mmHg

Question 20

How do you determine CaO2?

Answer 20

CaO2 = (PaO2) + (1.39 x mmHg Hb X % saturation)

Question 21

What is PiO2?

Answer 21

inspired oxygen

Question 22

What is PaCO2?

Answer 22

arterial CO2

Question 23

What is PaO2?

Answer 23

arterial O2

Question 24

When does A-a increase ?

Answer 24

aging, VQ mismatches, shunt, and diffusion impairment

Question 25

How is A-a measured?

Answer 25

pulse oximetry (SpO2), arterial blood gas analysis, A-s equation

Question 26

How does pulse oximetry work?

Answer 26

•Refracts light (red and infared) through region to see hemoglobin saturation, Oxyhemoglobin absorbs the infared light and the red light passes through

Question 27

What is the A-a equation?

Answer 27

A-a= [P1O2 - (PaCO2/0.8)-PaO2]

Question 28

How does O2 diffuse into tissues?

Answer 28

 Leaves hemoglobin, then goes into the plasma, then the concentration gradient forces them out into the tissues

Question 29

What does a left shift mean in the O2 saturation chart?

Answer 29

Hb will hold onto the O2 making the delivery of O2 more difficult.

Question 30

What does a right shift mean in the hemoglobin O2 saturation chart?

Answer 30

Hb affinity for O2 decreases, the delivery of O2 is facilitated

Question 31

What causes a right shift in the hemoglobin-O2 saturation chart?

Answer 31

drop in pH, increase in temp, increase in PCO2, increase in 2,3 DPG

Question 32

What causes a left shift in the hemoglobin-O2 saturation chart?

Answer 32

increase in pH, drop in temp, drop in PCO2, drop in 2,3 DPG

Question 33

Why does PCO2 change the pH?

Answer 33

there is a hydration reaction, H+ changes the pH; favored in RBCs

Question 34

Where is 2, 3 DPG present?

Answer 34

in red blood cells (product of glycolysis)

Question 35

Why is CO lethal?

Answer 35

when present, it steals O2’s spot and therefore no oxygen can be absorbed

Question 36

What are the main acids that we make in the body?

Answer 36

lactic and carbonic acids