Term
| What is the blood pressure (sys/dias) in the pulmonary arteries? |
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Definition
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Term
| is pulmonary vascular resistance higher or lower than systemic resistance? |
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Definition
lower
pressure drops from 30 to 10 mmHg over tissue capillaries, but it only drops from 12 to 8 mmHg over pulmonary capillaries |
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Term
| What is the diameter of alveolar capillaries compared to extra-alveolar capillaries? |
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Definition
alveolar capillaries are <50 um
extra-alveolar capillaries are >50 um
*Alveolar capillaries are supplied and drained by extra-alveolar vessels. |
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Term
| How is pulmonary vascular resistance calculated? |
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Definition
It is the sum of the resistances in the extra-alveolar and alveolar vessels.
total PVR = R1 + R2 + R3.... |
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Term
| Does PVR increase or decrease with an increase in pulmonary arterial pressure OR pulmonary venous pressure while holding the other pressures constant? |
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Definition
| PVR decreases by further distension of open vascular pathways and recruitment of closed vascular pathways |
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Term
| What dos the graph of PVRs over a range of lung volumes look like? |
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Definition
| It is U-shaped because PVR is high at low volumes because extra-alveolar vessels are small and it is high at high volumes because alveolar vessels are compressed |
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Term
| Which is more effective at decreasing total PVR -recruitment of more vessels or distension of existing vessels? |
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Definition
| distension (making radius larger) of existing vessels reduces resistance more |
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Term
| How is pulmonary blood flow calculated? |
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Definition
pulmonary blood flow = right CO = P/R
right cardiac output is equal to the pressure gradient across the lung (pulmonary arterial pressure - pulmonary venous pressure)/pulmonary vascular resistance
also: Fick's Principle can be used here:
pulmonary blood flow= right CO = O2 consumption of body/arterial to venous oxygen difference |
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Term
| How is cardiac output estimated using Fick's principle? |
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Definition
O2 consumption measured using a spirometer; systemic arterial and venous contents are measured by catheterization CO = VO2/(Ca - Cv)
Same as last flashcard...
pulmonary blood flow= right CO = O2 consumption of body/arterial to venous oxygen difference
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Term
| what is the density of blood? |
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Definition
1.06 kg/l
(water is 1 kg/l) |
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Term
| what zone of the lung is the Starling resistor effect seen in? |
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Definition
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Term
| What zone of the lung is waterfall flow seen in? |
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Definition
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Term
| What zone of the lung is distensive flow seen in? |
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Definition
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Term
| What zone of the lung would no flow be seen in? |
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Definition
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Term
| in the lung, does hypoxia induce vasoconstriction or vasodilation? |
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Definition
it induces vasoconstriction and decreased blood flow
(note that this is different than systemic capillaries) |
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Term
| how much water is in between the visceral and parietal pleura membranes? |
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Definition
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Term
| where does fluid that moves out of pulmonary capillaries go? |
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Definition
perivascular and/or peribronchial spaces
(It can eventually get into alveolar spaces) |
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Term
| where is angiotensin I converted to angiotensin II? |
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Definition
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Term
| what happens to bradykinin in the lung? |
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Definition
| it is (largely) inactivated |
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Term
| what hormones does the lung remove? |
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Definition
| serotonin (99%) and norepinephrine (30%) |
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Term
| what molecules besides hormones are removed by lungs? |
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Definition
| prostaglandins E and F20 and leukotrienes |
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Term
| what molecule does phospholipase A2 produce from membrane-bound phospholipid? |
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Definition
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Term
| what two enzymes act on arachidonic acid? |
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Definition
| lipoxygenase and cyclooxygenase |
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Term
| what molecules does lipoxygenase produce from arachidonic acid? |
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Definition
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Term
| what molecules does cyclooxygenase produce from arachidonic acid? |
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Definition
| prostaglandins and thromboxane A2 |
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