Pulmonary Blood Flow Flashcards
Why is pulmonary blood flow important?
without the optimal flow through the lungs, ventilation is of no use
Characterize pulmonary vessels.
have great dispensability and compliance, more capillaries than alveoli
In the pulmonary system, venous blood is in the _____ and arterial blood is in the _____.
arteries, veins
in pulmonary circulation, what induces vasoconstriction?
hypoxia
Pulmonary artery pressure is ___ of systemic arterial pressure.
1/6th
What does bronchiolar circulation supply?
nutritional blood to the tracheobronchial tree up to the terminal bronchiole, hilar lymph nodes, visceral pleura, pulmonary artery and vein, vagus nerve, and esophagus
How does the bronchial and pulmonary system communicate?
via a shunt
What is difference in pressures in the A-a pressure gradient?
5-10 mmHg
Which has higher pressure: bronchial circulation or pulmonary circulation?
bronchial circulation
Is resistance higher in pulmonary or systemic circulation?
pulmonary
What is the mean pulmonary vascular resistance?
15 mmHg
What is Poiseulle’s law for volume flow rate?
P1-P2 = Q (with a dot) x R
What is P1 in Poiseulle’s law for volume flow?
pressure at the beginning of the tube in mmHg
What is P2 in Poiseulle’s law for volume flow?
pressure at the end of the tube in mmHg
What is Q in Poiseulle’s law for volume flow?
flow (mL/minute)
What is R in Poiseulle’s law for volume flow?
resistance (mmHg/mL/minute)
How do you calculate pulmonary vascular resistance?
PVR = (MPAP-MLAP)/pulmonary blood flow
True or False: Pulmonary capillaries cannot stretch with change in resistance
False: they are distensible
What happens to the small capillaries when the volume of the lung increases?
the alveoli inflate, and they are pinched
When is the PVR the lowest?
when functional residual capacity is met
How do you explain a fall in PVR during exercise?
recruitment and distention; they have to decrease resistance to compensate for increased flow to keep change in pressure the same
How does more smooth muscle affect pulmonary arterial pressure?
it increases it (hypoxia)
What species are highly susceptible to hypoxic vasoconstriction?
cattle and pig
How does localized hypoxia affect pulmonary flow?
it redistributes it
What is EIPH?
exercise induced pulmonary hemorrhage
What causes EIPH?
high vaccuum during excercise that increases the transmural pressure difference, the barrier breaks, and the red blood cells end up in the alveoli
In zone 1 of the lung, rank these pressures from highest to lowest(during ventilation); PA, PV, Pa.
PA > Pa> Pv
What happens in zone 1 of the lung during ventilation?
there is no blood flow, alveolar pressure is pinching the vessels, not usually seen
In zone 2 of the lung, rank these pressures from highest to lowest (during ventilation); PA, PV, Pa.
Pa > PA > Pv
What happens in zone 2 during ventilation?
intermittent blood flow
In zone 3 of the lung, rank these pressures from highest to lowest (during ventilation); PA, PV, Pa.
Pa > PV > PA
What happens in zone 3 during ventilation?
high hydrostatic pressure, distended vessels, high blood flow
What is Starling’s equation important in determining?
the amount of fluid flowing per minute
What causes an increase in Pcap?
exercise
When does clinical edema develop?
the lymphatic capacity is exceeded, proteoglycan bridges break, and fluid enters the alveoli and bronchioles
Why does pulmonary edema fluid look foamy?
because it is a mixture of edema fluid and surfactant
What does decreased plasma oncotic pressure cause?
hypoproteinemia, increased vascular permeability, inflammation, lymphatic obstruction
What does lung edema impede on?
ventilation and oxygenation
How is pulmonary fluid reabsorbed?
through stomata on the parietal fleura, and then through the lymphatics
