Pulmonary Circulation Oct13 M1 Flashcards

1
Q

what prof says about pulmonary arteries

A

carry partially deoxygenated blood

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2
Q

what prof says about pulmonary veins

A

carry oxygenated blood

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3
Q

what prof says about bronchial veins

A

carry partially deoxygenated blood

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4
Q

example of physiological shunt

A

bronchial veins mostly drain into pulmonary veins rather than venous circulation

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5
Q

pulmonary arteries characteristics

A

thin wall, diameter changes easily with pressures

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6
Q

pulmonary vascular resistane

A

resistance in pulmonary circulation

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7
Q

what drives movement in pulmonary circulation

A

Pa (pulm artery) - PLA (left atrium)

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8
Q

something particular about the pulmonary vascular resistance

A

decreases as flow increases

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9
Q

why PVR decreases as flow increases

A

alveolar distension

alveolar recruitment

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10
Q

relationship between pressure and flow across the pulmonary circulation

A

non-linear. at higher flows, the same pressure gradient produces greater increase in flow (bc resistance lower)

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11
Q

how lung volume affects the resistance of pulmonary vessels

A
alveolar vessels (septum) get narrower
extra-alveolar vessels expand
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12
Q

why extra-alveolar vessels expand with change in pressure

A

because are attached to surrounding lung tissue so traction force

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13
Q

pulm vessels resistance at volume greater than TLC (intra and extra alveolar)

A

alveolar vessels: R increases

extra-alveolar: R decreases

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14
Q

extra alveolar vessels resistance at volume lower than FRC

A

increased

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15
Q

what influences pulmonary vascular resistance (diameter) the most (2)

A

transmural pressure and lung volume

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16
Q

how pulmonary blood flow varies across the lung + reason

A

increases as you go from top to bottom and slightly drops at very bottom. Gravity

17
Q

West’s zones of the lung

A

Zone 1: top
Zone 2: middle
Zone 3: bottom

18
Q

what determines blood flow across a lung zone

A

Pa, Pv and PA

19
Q

lung zone 1

A

Palv greater than Pa greater than Pv

20
Q

lung zone 2

A

pa greater than p alv greater than pv. waterfall condition

21
Q

zone 4 of the lung

A

pa greater than pv greater than palv

22
Q

what determines flow in lung zones

A

1: palv-pa
2: pa-palv
3: pa-pv

23
Q

how pulmonary vessels adapt with certain substances

A

constrict with hypoxia and low pH

dilate with NO bc relaxes SM

24
Q

how systemic vessels adapt to hypoxia

A

dilate and dilate more if low pH

25
Q

why need to keep alveolar surface dry (and why is this a problem)

A

for gas exchange

problem bc tendency of fluid in blood to go in alveolar space. (P hydros greater than P oncotic)

26
Q

what mechanism prevents fluid accumulation in lung interstitium

A

lymphatics

27
Q

interstitial vs alveolar pulmonary edema

A

interstitial: lymphatics can’t handle fluid, excess fluid in pulmonary intersitium
alveolar: interstitial P raised so much it broke alveolar epithelial membranes, fluid leak in alveoli

28
Q

cardiogenic pulmonary edema

A

left heart failure so blood pooling in pulmonary circulation

29
Q

pleural effusion on CXR

A

one lung’s bottom is higher than the other lung.