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17 Cards in this Set
- Front
- Back
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What are the four differences between pulmonary and systemic circulation?
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1) pulmonary circulation is at a lower mean pulmonary pressure than mean arterial pressure
2)pulmonary arteries have less smooth muscle and thinner walls 3) the resistance for pulmonary circulation is pulmonary vascular resistance and the resistance for systemic circulation is systemic vascular resistance 4) capillaries can be collapsed in high alveolar pressure |
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How do you calculate pulmonary vascular resistance?
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PVR = Pulmonary mean arterial pressure - pulmonary mean venous pressure / CO
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what are the values for mean pulmonary arterial pressure and mean systemic arterial pressure (aortic pressure)?
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1) mean pulmonary arterial pressure is 15
2) mean systemic arterial pressure is 100 |
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what are the common values that you need to know to calculate pulmonary vascular resistance (PVR)?
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pulmonary mean arterial pressure (15 mmhg), pulmonary venous pressure = 8mmhg and blood flow/co is 5L/min
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What is the basic overview of the section on distribution of pulmonary blood flow?
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1) the different positions/zones from apex to base mean that there are different gravitational pulls on the arterial blood.
2. this creates an arterial pressure 3. the value of the arterial pressure created relative to the value of the alveolar pressure created will determine whether or not blood will flow or how fast |
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What is the case of the three parts of the lung in terms of distribution of blood flow
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Apex - little/no flow , PA>Pa>Pv
Middle - flow - Pa>PA>Pv Base - Pa>>>Pv>PA |
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What are the three big categories of regulators of pulmonary blood flow?
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1) Passive
2) Hypoxic vasoconstriction 3) chemical |
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What are the different kinds of Passive regulators of pulmonary blood flow?
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1) Passive - gravity and volume
2) hypoxic vasoconstriction 3) chemical - thromboxane, endothelins, prostglandin, |
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What are the two clinical situations relevant to hypoxjc vasoconstriction?
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high altitude
pregnancy |
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What happens with high altitude in hypoxic vasoconstriction?
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high altitude --> decrease barometric pressure --> decrease PO2 in lungs --> decreased P02 causes an increase in PVR next to those hypoventilated alveoli and diverts blood away from them
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What happens in fetus?
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fetus can not breathe so it has no way to perfuse its pulmonary capillaries so it does not get any until it gets oxygen at its first breath and expands its lungs to open the alveoli and vessels
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What are the chemical components?
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thromboxane - vasoconstriction
prostglandin - vasodilator endothelin - vasoconstrictor |
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How does the passive mechanisms work?
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gravity - increases Pa at the bottom and that increases blood flow in base
lung expansion - opens up vessels and decreases PVR |
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What is the relatoinship between alveolar ventilation and alveolar PCO2?
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PACO2= VCO2 *K/VA
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What are all the things this equation stands for?
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PACO2 - alveolar PCO2
VCO2 - CO2 produced in body VA - alveolar ventilation |
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what is the golden rule about PACO2 and ventilation and PaCO2?
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You hold the rate of VCO2 constant, Ventilation will determine arterial and alveolar PCO2
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What is the relationship between alveolar ventilation and PaCO2?
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inversely proportional because when you exhale there is 0 CO2 in the surronding air but alot in your blood so it picks it up from pulmonary artery and takes it into alveoli
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