5918910
Description
Flashcards by Alyse Holmes, updated more than 1 year ago
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Created by Alyse Holmes
over 10 years ago
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| Question | Answer |
| systolic pulmonary artery pressure | 25mmHg |
| diastolic pulmonary artery pressure | 8mmHg |
| Mean pulmonary artery pressure | 15 mmHg |
| Capillary Pulmonary pressure | 7 mmHg |
| Systolic Pressure in R ventricle | 25 mmHg |
| Pulmonary wedge pressure estimates | LA pressure |
| Normal Pulmonary Wedge Pressure | 8-10mmHg |
| pulmonary vascular resistance | 1/10th that of SVR |
| ratio of total systemic vascular resistance to pulmonary vascular resistance | 10:1 |
| Mean PA pressure | 15 |
| Mean Aortic Pressure | 100 |
| LA pressure | 5 |
| RA pressure | 2 |
| pressure differences from inlet to outlet of pulmonary and systemic systems are (15-5)=10 for pulmonary and (100-2)=98 for systemic circulation which is | a factor of 10 |
| describe pulmonary circulation | low pressure, low resistance, high compliance system |
| total resistance of pulmonary circulation is less than 1/10 that of the systemic system | true |
| What causes pulmonary circulation to be a low resistance system? | pulmonary blood vessels are generally shorter and wider than systemic vessels. There are many arterioles in pulmonary circulation with low resting vascular tone. |
| Pulse pressure of pulmonary system | 25 - 8 = 17 |
| alveolar vessels | surround the alveoli and are exposed to mechanical expansion of alveoli |
| extra-alveolar vessels | larger vessels exposed to changes in intrapleural pressure |
| Lung inflation collapses | alveolar vessels via stretch of alveolar wall |
| lung inflation expands | extra-alveolar vessels via radial traction |
| transmural pressure | pressure difference between the inside and outside of the capillary |
| resistance of alveolar vessels depends on | transmural pressure gradient and lung volume |
| Pressure inside alveolar vessels | varies with the cardiac cycle (pulsatile flow) and depends on vertical position relative to left atrium (higher the vessel, the lower the pressure) |
| pressure in alveoli | vary with the respiratory cycle, alveolar pressure is negative during inspiration and positive during expiration |
| Increases in lung volume simultaneously | tends to crush alveolar vessels, increasing resistance while expanding extraalveolar vessels, decreasing resistance |
| pulmonary vascular resistance is | 1/10 that of systemic circulation |
| pulmonary blood flow | 6L/min |
| PVR = | 1.7mmHg/L/min |
| Increase in perfusion pressure (pulmonary artery pressure) results in | distention and recruitment, decreasing PVR |
| Distention | increases in caliber or diameter of vessels |
| what is the predominant mechanism for fall in PVR when vascular pressures are high? | distention |
| What is the primary mechanism for fall is PVR when pulmonary artery pressure is raised from low levels? | recruitment |
| when a patient is upright, perfusion Q is greatest | near the base of the lungs and falls toward low levels near the apex |
| distribution of blood flow os affected by | posture and gravity |
| zone 1 | P alveolar > P arterial > P venous, not present in healthy lungs, may be present in severe hemorrhage or positive pressure ventilation |
| zone 1 = | ventilated but NOT perfused, alveolar dead space. |
| Zone 2 | P arterial > P alveolar > P venous, flow depends on arterial-alveolar pressure difference, blood flow intermittant, blood vessels behave like collapsible tubes. |
| Zone 3 | P arterial > P venous > P alveolar, continuous flow, flow depends on arterial-venous pressure difference |
| hypoxic pulmonary vasoconstriction | alveolar gas falls below normal, active vasoconstriction of adjacent vessels occurs during alveolar hypoxia, prevents perfusion of areas of lungs that are not adequately ventilated. |
| angiotensin 1 | converted to angiotensin II by ACE |
| Bradykinin | Up to 80% inactivated |
| Serotonin | almost completely removed |
| norepinephrine | up to 30% removed |
| Leukotrienes | Almost completely removed |
| Prostaglandins E2 and F2 alpha | almost completely removed |
| leukotrienes are generated by | lipoxygenase pathway. |
| prostaglandins and thromboxane A2 | come from the cyclooxygenase pathway |
| prostaglandins | potent vasoconstrictors or vasodialators. affect platelet aggregation. have a role in bronchoconstriction in asthma. |
| prostaglandin E2 | important role in fetus bc it helps relax the patent ductus arteriousus |
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