Diffusion & Perfusion Flashcards

1
Q

_____ is the arterial oxygen content, which is the total concentration of O2 in blood.

A

CaO2

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

CaO2 is the arterial oxygen content, which is the _____.

A

total concentration of O2 in blood

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

For a healthy person CaO2 is about _____ or _____ O2/100 ml blood.

A

9.1 mM; 20.7 ml

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

Why isn’t very much O2 dissolved in the blood?

A

it’s not very soluble and it quickly binds to hemoglobin

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

What is the solubility coefficient?

A

the tendency of any molecule to dissolve in a liquid

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

What is the tendency of any molecule to dissolve in a liquid called?

A

the solubility coefficient

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

CO2 is about ______ more soluble in blood than O2.

A

20 times

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

How is O2 flux maximized across the alveolar membrane?

A
  1. large SA of the alveolar membrane
  2. thin membrane width (d)
  3. large O2 pressure gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

During ______, when there is thickening of the alveolar walls (increased d), the rate of diffusion is slowed.

A

interstitial disease

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

During interstitial disease, when there is thickening of the alveolar walls (increased d), the rate of diffusion is ______.

A

slowed

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

Name 3 ways diffusion can be altered.

A
  1. interstitial disease (thickened alveolar walls)
  2. emphysema (decreased SA)
  3. changed hemoglobin concentration (polycythemia, anemia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does perfusion limited mean?

A

conditions do permit rapid equilibration of blood with alveolar air (only factor is blood flow); PO2 and PCO2 in blood exiting the pulmonary exchange area is similar to alveolar PO2 and PCO2

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

What does diffusion limited mean?

A

conditions DO NOT permit complete equilibration of alveolar air and blood; the PO2 in the blood exiting the pulmonary exchange area will be less than alveolar PO2

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

_____ is the blood flow of the pulmonary circulation available for gas exchange (in one minute).

A

Perfusion, Q,

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

Perfusion, Q, is _____.

A

the blood flow of the pulmonary circulation available for gas exchange (in one minute)

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

Perfusion equals the cardiac output, which for an

adult at rest is _____.

A

= 5 liters/ min

17
Q

Perfusion equals ______, which for an adult at rest is Q = 5 liters/ min.

A

the cardiac output

18
Q

At any given time, there is about _____ of blood in the lung, comprising 40% of the lung weight.

A

500 ml

19
Q

At any given time, there is about 500 ml blood in the lung, comprising ____% of the lung weight.

A

40

20
Q

What factors regulate perfusion?

A
  1. O2 tension
  2. chemical agents (thromboxane, prostacyclin)
  3. capillary recruitment
  4. gravity
21
Q

The factor of overriding importance in governing minute to-minute regulation of the pulmonary circulation is the ______.

A

alveolar O2 tension, PAO2

22
Q

______ causes constriction of the nearby arterioles.

A

Low alveolar PO2

23
Q

Low alveolar PO2 ______ the nearby arterioles.

A

constricts

24
Q

What is hypoxic pulmonary vasoconstriction?

A

a decrease in local blood flow in the lung to shift it to other regions

25
Q

Where do thromboxane and prostacyclin come from?

A

arachadonic acid

26
Q

______ is the most important vasoconstrictor.

A

Thromboxane A2

27
Q

Thromboxane A2 is the most important ______.

A

vasoconstrictor

28
Q

________ is a potent vasodilator.

A

Prostacyclin

29
Q

Prostacyclin is a potent _______.

A

vasodilator

30
Q

Because of _____, the pulmonary blood pressure is low at the apex of the lung.

A

gravity

31
Q

Because of gravity, the pulmonary blood pressure is low at the _____ of the lung.

A

apex

32
Q

What is a shunt?

A

blood perfusion where there is no ventilation

33
Q

What is it called when there is blood perfusion where there is no ventilation?

A

a shunt