Respiration 3 Flashcards

1
Q

What is movement of gas proportional to

A

Pressure gradient

Solubility of gas in liquid

Temp

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2
Q

What is Dalton’s law of pressure

A

Pressure from a mix of gases = sum of the partial pressure from 1 gas

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3
Q

What is partial pressure of gas dependent on

A

It’s abundance in the atmosphere

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4
Q

If 78% of atmosphere is nitrogen what is the pp N

A

78%

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5
Q

What needs to be taken into account with alveolar air when measuring partial pressures of o2, co2 and nitrogen

A

The water vapour / h20

Need to measure dry gases only

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6
Q

What is solubility in liquid dependent on

A

Temp and partial pressure

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7
Q

In a partial pressure gradient , what happens to o2

A

It will move to liquid and only some will dissolve

It isn’t as soluble as co2

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8
Q

Why does o2 need carriers in blood

A

It’s lack of solubility in liquid

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9
Q

Why would oxygen move to the blood because of partial pressure and co2 out into alveoli

A

Pp o2 is lower in the blood than alveoli so moves into blood

Ppco2 higher in blood so moves into alveoli

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10
Q

Why can co2 easily move into alveoli

A

It is more soluble in liquid

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11
Q

Why doesn’t temp impact diffusion

A

It’s always at body temp

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12
Q

Why is large perfusion/ blood flow to the lungs better for diffusion

A

They run parallel to the bronchioles and close capillary to alveoli type 1 cells = reduces diffusion pathway

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13
Q

What is ficks law of diffusion

A

Flux = permeability x Conc gradient / distance

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14
Q

Which ficks diffusion variable can change

A

Concentration gradient (permeability and distance doesn’t change in blood and alveoli)

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15
Q

Explain the pressures which allow o2 to diffuse from alveoli into tissues

A

100 mmhg at alveoli vs 40 mmhg at the capillaries

O2 moves in

Capillaries now have 100mmhg compared to tissues with 40mmhg = diffusion into tissues

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16
Q

Explain how co2 gets from tissues due to partial pressures

A

46 mmhg at tissues vs 40 in blood system = diffusion into blood

46 now in blood = diffusion into alveoli due to it being 40mmhg

17
Q

What is the effect of pp02 and co2 and ventilation

A

Hypoventilation = increased PPc02 and low ppo2 in the alveoli

Hyperventilation = high ppo2 in the alveoli and low ppco2 (more removed)

18
Q

What is the therapy called used to treat low ppo2 in the lungs eg due to anemia or blood loss

A

Hyperbaric oxygen therapy

19
Q

What does hyperbaric oxygen therapy allow

A

More exchange of o2 to the tissues

20
Q

How does emphysema cause lack of exchange due to lack of diffusion

A

Depletion of alveoli, not many alveoli decreases SA for gas exchange

21
Q

Which 2 ways does restrictive fibrosis decrease diffusion

A

Reduces alveoli permeability by increasing its thickness (affect in ficks law)

Also lack of elastic on lungs causes lack of lung compliance and ventilation

22
Q

How does edema increase diffusion distance

A

Produces fluid in the interstitial space

This means there’s a lack of o2 gradient because it’s not as soluble in liquid as co2

23
Q

How does asthma affect gas exchange / diffusion

A

Obstruction to ventilation decreases ppo2 in the system

Low FEV1

24
Q

Explain the levels of perfusion vs ventilation at the base and top of lungs

A

At base of lungs there is more blood flow than ventilation

At top of lungs too much ventilation and not enough perfusion

25
What does lack of ventilation at base of lungs cause
Lack of oxygenation to match the large blood flow
26
What does high ventilation and low perfusion st top of lungs cause
Dead space (air removed before exchange)
27
What would affect ventilation at the top of lungs
Posture and rate of ventilation | Upright causes high in top of lungs
28
Ventilation perfusion matching allows levels to be at ....
0.9-1
29
How is lack of ventilation at base meaning lack of oxygenation of blood overcome
Hypoxic pulmonary vasoconstriction
30
What does hypoxic pulmonary vasoconstriction do
If low po2 is sensed eg in base of lungs then vasoconstriction allows redirection of blood to other areas of high p02
31
What happens when po2 is increased in alveoli
Vasodilation of vessels / arterioles
32
What do bronchioles respond to in hypoxic pulmonary vasoconstriction
Pco2 levels in the blood
33
What happens when there is low pco2 in blood
Bronchioles will constrict as exchange doesn’t need to happen
34
When do bronchioles vasodilate
When pco2 is too high in the blood ie 46 mmhg Needs exchanging out of body
35
What is Henry’s law
At constant temp, the amount of gas dissolved in liquid is dependant on the solubility and the partial pressure of the gas