Principles of gas exchange Flashcards

1
Q

effects of high altitude

A

at high altitude there is a decrease in total pressure

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2
Q

each gas in a mixture is ___ of other gases present and exerts a __ according to its concentration

A

independent, pressure

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3
Q

inspired air is humidified, water vapor has a

A

partial pressure

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4
Q

the amount of gas dissolved in a liquid is __ to partial pressure

A

proportional

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5
Q

there is a ___ relationship between partial pressure of O2 and amount dissolved

A

linear

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6
Q

ways to increase diffusion of gases

A

increase membrane area
increase amount dissolved
increase partial pressure difference
decrease membrane thickness

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7
Q

gases move by

A

simple diffusion

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8
Q

diffusing capacity

A

the amount of a gas the lungs can transfer to the blood (O2)

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9
Q

perfusion-limited

A

diffusing capacity is limited by blood flow
- need to increase blood flow to the lungs to increase amount of O2 delivered to the blood

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10
Q

diffusion-limited

A

diffusing capacity is limited by rate of diffusion
- need to increase the rate of diffusion to increase the amount of O2 delivered to the blood

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11
Q

diffusing capacity of O2 is

A

perfusion limited
- O2 in alveoli and the blood comes to equilibrium, therefore increasing the rate of diffusion will not add O2 to the blood, so must increase blood flow

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12
Q

in disease conditions, if the O2 in the blood does not come to equilibrium with the alveoli, the diffusion capacity of O2 would now be

A

diffusion limited

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13
Q

O2 in alveoli come to equilibrium 1/3 of the way through the capillary so even if blood velocity increases (exercise) the O2 in the blood will come to equilibrium with alveoli

A

important

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14
Q

the pulmonary circulation is a __ pressure system compared to the systemic circulation

A

low

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15
Q

congestive (left) heart failure

A

blood builds up in pulmonary circulation, pulmonary capillary pressure increases, filtration at capillaries, pulmonary edema, poor gas exchange (potential death)

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16
Q

recruitment

A

open more capilaries

17
Q

if there is not decrease in TPR during exercise then

A

increase MAP, filtration in lungs, pulmonary edema, death

18
Q

distension

A

increase radius of each capillary

19
Q

3 benefits of recruitment and distension

A

decreased resistance causes decreased pressure and prevents filtration
decreases velocity of blood flow so more time for gas exchange
increases surface area for gas exchange

20
Q

effect of autonomic NS on pulmonary vascular resistance

A

not an important regulator

21
Q

effect of hypoxia (low O2)

A

always want to match air flow and blood flow
- decreased air flow = decreased O2 = vasoconstriction
- decrease air flow leads to decreased blood flow

22
Q

PO2 in the air is 160 mmHg but PO2 in alveoli is 105 mmHG, why the decrease

A

mine with dead space air
mixing with residual volume air
air is humidified (water vapor added)

23
Q

shunting

A

some blood does not go past alveoli, the PO2 in this blood stays at PO = 40 mmHg