Final: Lecture 24 Flashcards

0
Q

Boyle’s Law

A

•For a fixed amount of an ideal gas kept at fixed temp, pressure and volume are INVERSELY proportional

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

Dalton’s Law

A

•Total pressure exerted by the mixture of non-reactive gasses is equal to the sum of the partial pressures of individual gasses

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

Henry’s Law

A

•At constant temp, the amount of a given gas that dissolves in a given type and volume of liquid is Directly proportional to the partial pressure of that gas in equilibrium with that liquid

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

Ideal Gas Law

A

•P = nRT/V

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

Pressure is ________ proportional to the concentration of the gas molecules.

A

•Directly

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

Rate of diffusion is _______ proportional to pressure caused by that gas alone.

A

•Directly

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

Partial pressure of O2 at alveolar membrane is ___. CO2 is ___.

A
  • 150 mm Hg

* .21 mm Hg

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

Vapor Pressure

A
  • Of water is the partial pressure exerted to escape from the liquid phase to the gas phase.f
  • At normal body temp (37º C) this vapor pressure is 47 mm Hg
  • Vapor pressure of water depends on the temp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Factors that affect rate of gas diffusion in a fluid

A
  • Solubility of gas in the fluid
  • Cross-sectional area of fluid
  • Distance through which the gas must diffuse
  • Molecular weight of gas
  • Temp of fluid (remains reasonably constant)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Alveolar Air Replacement

A
  • Residual capacity of lungs is 2300 ml, only 350 ml of new air brought into alveoli with each normal inspiration
  • Same amount of old alveolar air is expired
  • Therefore volume of alveolar air replaced by new is only 1/7th, so multiple breaths are required to exchange most of the alveolar air
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Oxygen concentration in the alveoli, as well as its partial pressure, is controlled by?

A
  • Rate of absorption of oxygen into blood
  • Rate of new oxygen entry into the lungs (alveolar ventilation)
  • To quadruple oxygen consumption, alveolar ventilation must also quadruple
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

CO2 concentration in the alveoli, as well as its partial pressure, is controlled by?

A
  • Rate of CO2 excretion, alveolar pCO2 increases in direct proportion to rate of excretion
  • Alveolar ventilation: alveolar pCO2 decreases in inverse proportion to alveolar ventilation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Factors that determine how rapidly a gas will pass through the respiratory membrane:

A
  • Membrane thickness
  • Membrane surface area
  • Diffusion coefficient of gas in the substance of the membrane
  • Partial pressure difference of gas between the two sides of the membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Any factor that increases membrane thickness (i.e. edema or fibrosis) to more than 2x or 3x normal can interfere with?

A

•gas exchange*

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

Ventilation-perfusion ratio

A
  • = Va/Q = alveolar ventilation/blood flow

* Va/Q - 0.8

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

Va/Q = 0 when Va = 0 but there is still perfusion:

A
  • Due to airway obstruction (i.e. mucus plug)

* Blood gas composition remains unchanged

16
Q

Va/Q = infinity when Q = 0 but there is still ventilation (no gas exchange):

A
  • Due to vascular obstruction (i.e. pulmonary embolism)

* Alveolar gas composition remains unchanged b/c there is no blood contact. This creates a physiologic shunt.

17
Q

Shunted blood is…

A
  • Whenever Va/Q is below normal a certain fraction of the venous blood passing through the pulmonary capillaries does not become oxygenated
  • Greater the physiologic shunt, greater the amount of blood that fails to be oxygenated