Human Phys 6.6 Flashcards

1
Q

What percentage of dissolved O2 accounts for total O2 content in the blood?

A

2%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What form of O2 produces a partial pressure?

A

Dissolved gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What drive diffusion?

A

Partial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is O2 bound to?

A

Hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What percentage does bound gas account for?

A

98%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Does bound gas contribute to partial pressure?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does CO2 get modified into?

A

HCO3 by carbonic anhydrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is perfusion limited gas exchange limited by?

A

Amount of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is diffusion limited gas exchange limited by?

A

Strenuous exercise

Emphysema and fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the only way to get more diffusion?

A

Get more blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does pulmonary blood flow determine?

A

O2 transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do both O2 and CO2 bind to for transport?

A

Hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why does O2 reach diffusion equilibrium while CO2 does not?

A

Hemoglobin in mixed venous blood is already about 75% saturated with O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When does blood become almost fully saturated with oxygen?

A

By the time it passed through 1/3 of the pulmonary capillary and little additional oxygen normally enters the blood during the later 2/3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How long does the blood stay in the lung capillaries to cause full oxygenation?

A

3x as long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How many molecules of O2 can each molecule of hemoglobin bind?

A

4 molecules of O2

17
Q

What is the PO2 when the arterial blood reaches the peripheral tissues?

A

95mmHg

18
Q

What is the PO2 in the interstitial fluid that surrounds the tissue cells?

A

40mmHg

19
Q

What is the % saturation?

A

Function of PO2 of blood

20
Q

P50

A

The PO2 at which hemoglobin is 50% saturated

21
Q

What does an increase in P50 indicate?

A

Drop in affinity

22
Q

What can we tolerate significant drops of PO2 in without significant changes in O2 carried by hemoglobin?

A

From 100-60mmHg

23
Q

What does a right shift of the O2 hemoglobin dissociation curve mean?

A

Hemoglobin more likely to let go O2 (low affinity)

24
Q

What does a left shift of the O2 hemoglobin dissociation curve mean?

A

Hemoglobin hangs on to O2 (high affinity)

25
Q

What causes a right shift in the O2 hemoglobin dissociation curve?

A

Increase PCO2

Increase temperature

Increase 2.3-DPG

Decrease pH

26
Q

What causes a left shift in the O2 hemoglobin dissociation curve?

A

Decrease PCO2

Decrease temperature

Decrease 2.3-DPG

Increase pH

27
Q

What is the amount of dissolved CO2?

A

5%

28
Q

What is the amount of CO2 bound to hemoglobin?

A

3%

29
Q

What is the amount of CO2 modified to bicarbonate?

A

90%

30
Q

How much faster can CO2 diffuse than O2?

A

20x faster

31
Q

What are the pressure differences needed to cause CO2 diffusion?

A

Much less than those needed to cause O2 diffusion

32
Q

Diffusion of O2 to capillary blood

A

PO2 = 160

Enters trachea and PO2 drops to 150

Reaches alveolar air PO2=100 and PCO2= 40

Mixed venous blood comes in with a PO2=40 and PCO2=46

O2 moves in CO2 moves out and as the blood passes alveolar air and changes blood to PO2=100 and PCO2=40

33
Q

What does it mean when systemic arterial blood equals the alveolar air?

A

Blood is fully oxygenated