Video 3 Blood Gas transport

Question 1

What is the partial pressure of oxygen? How do you calculate it?

Answer 1

160 mmHg
0.21 (concentration of oxygen) x 760 mmHg (barometric pressure)

Question 2

When air is inspired it is _______ and _______ and saturated with _________ at _______ degrees celcius.

Answer 2

warmed
moistened
water vapor
37

Question 3

What is the partial pressure of water vapor at 37 degrees?

Answer 3

47 mmHg

Question 4

What needs to be considered when calculating the partial pressure of oxygen? How is it calculated?

Answer 4

The inspired gas is moist, subtract the partial pressure of water vapor from the barometric pressure before multiplying by 0.21
760-47= 713 mmHg
0.21 x 713 mmHg= 150 mmHg

Question 5

What is the partial pressure of oxygen in water if equilibrated to oxygen in air?

Answer 5

150 mmHg

Question 6

What is the concentration of oxygen in air vs water? Why such a difference?

Answer 6

21 ml/dl vs 0.45 ml/dl
The solubility of oxygen in water is very low

Question 7

PO2 in arterial blood

Answer 7

100 mmHg

Question 8

Amount of oxygen dissolved in arterial blood

Answer 8

0.3 ml/dl OR 3ml/liter

Question 9

Why isnt oxygen in solution sufficient for our tissues?

Answer 9

oxygen in transport (hemoglobin) is required because the maximum O2 available in solution is 90 ml/min assuming a cardiac output of 30 liters/min during exercise. The O2 requirement at that level is 3000 ml/min

Question 10

Structure of hemoglobin

Answer 10

4 heme molecules, 4 polypeptide chains (2 alpha and 2 beta)

Question 11

Hemoglobin A vs hemoglobin F

Answer 11

adult vs fetal

Question 12

Fetal Hb has a high ______

Answer 12

oxygen affinity

Question 13

Describe sickle cell hemoglobin

Answer 13

one chain is altered due to mutation

Question 14

What is oxygen capacity?

Answer 14

The total amount of oxygen that the blood can carry attached to hemoglobin

Question 15

Why is the oxygen dissociation curve sigmodoidal shaped?

Answer 15

due to the confirmation change the hemoglobin undergoes as oxygen attaches; after one oxygen molecule attaches, the affinity goes up

Question 16

In arterial blood, with a PO2 of 100, what is the oxygen concentration?

Answer 16

Nearly 100% (97%)

Question 17

What is mixed venous blood?

Answer 17

Blood in the pulmonary artery coming into the lung

Question 18

Venous blood has a PO2 of _______ and an O2 saturation of ______

Answer 18

40 mmHg
75%

Question 19

What is P50? What is the normal value in arterial blood?

Answer 19

Partial pressure of oxygen for 50% saturation
27 mmHg

Question 20

How to calculate total oxygen concentration of blood

Answer 20

Total O2 = 1.39 x Hb x %saturation/100 + (0.003 x PO2)

Question 21

How much oxygen can combine with hb?

Answer 21

one gram of Hb can combine with 1.39 ml of oxygen

Question 22

Normal hemoglobin level

Answer 22

15 g/dl

Question 23

Shifting the oxygen dissociation curve to the left has what effect on affinity

Answer 23

increased affinity; the oxygen saturation for a given PO2 is increased

Question 24

What 4 factors shift the dissociation curve to the right?

Answer 24

1. Temp
2. increased P CO2
3. increased H ion concentration
4. increased 2,3 DPG

Question 25

An exercising muscle favors a shift in what direction on the dissociation curve?

Answer 25

Shift to the right; want to unload more oxygen

Question 26

what is 2,3 DPG

Answer 26

product of red cell metabolism

Question 27

Describe CO affinity for hemoglin

Answer 27

extremely high; about 240 times that of oxygen

Question 28

If 33% of Hb is bound to CO, does the affinity for oxygen increase or decrease? what effect does this have?

Answer 28

increase It is difficult to unload the oxygen in the periphery

Question 29

3 forms that carbon dioxide is carried in the blood

Answer 29

1. dissolved 2. as bicarb 3. as carbamino compound

Question 30

Compare the solubility of oxgyen to that of CO2

Answer 30

0.003 ml.dl vs 0.067 ml/dl

Question 31

carbon dioxide combines with water to form? what enzyme helps speed up this reaction?

Answer 31

carbonic acid carbonic anhydrase

Question 32

Where does CO2 bind to Hb? what does it form?

Answer 32

terminal amine group carbamino hemoglobin

Question 33

T/F: Plasma contains carbonic anhydrase

Answer 33

False; it is only in red blood cells

Question 34

carbonic acid dissociates to

Answer 34

bicarb and a Hydrogen ion

Question 35

Reduced Hb combines with ______ much more easily than _______ Hb

Answer 35

protons oxygenated

Question 36

The lower the oxygen saturation in the blood, the better it is to take up?

Answer 36

CO2

Question 37

What causes the chloride shift into the red blood cells?

Answer 37

The H ions inability to diffuse across the cell wall like bicarb after disassociation of carbonic acid . Chloride ions shift to balance the electronegativity

Question 38

All of the processes happening in the RBC cause?

Answer 38

water to shift into the cell due to the increased osmolarity

Question 39

Of the 3 forms of CO2 carriage in arterial blood, which is the most prevalent? What about mixed blood?

Answer 39

90% is carried by bicarb. Bicarb is also most prevalent in mixed blood, however the percentage is 60%

Question 40

Why it a result of a more linear and steeper CO2 dissociation curve when compared to oxygen?

Answer 40

The difference in partial pressure between the arterial and the mixed venous blood is much less for CO2 than oxygen

Question 41

What is the Boehr effect?

Answer 41

Reducing CO2 increases oxygen affinity