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99 Cards in this Set
- Front
- Back
Where are discontinuous capillaries often found?
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sinusoids of liver, spleen, and bone marrow
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What characteristics of capillaries make them ideal for rapid diffusive exchange?
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-extreme proximity to cells
-large surface/volume ratio -low flow velocity -thin walls |
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What metabolites can undergo transcellular transcapillary exchange?
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small nonpolar molecules:
-O2 -CO2 |
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What metabolites can pass through intercellular clefts in transcapillary exchange?
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-K+
-glucose -Na+ -Cl- |
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What are the 3 mechanisms that can increase transcapillary exchange?
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-capillary recruitment
-increased tissue concentration gradients -increased blood flow |
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For what types of solutes will increased blood flow cause increased transcapillary exchange?
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small nonpolar molecules which cross capillary walls easily (e.g. O2)
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What is Starling's principle of fluid exchange?
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-fluid filtration = k[(Pc - Pi) - (πc - πi)]
-fluid filtration = hydraulic drive - osmotic suction |
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What 4 parameters influence Pc most strongly?
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-distance along capillary
-arterial and venous pressures -gravity -sympathetic vasomotor tone |
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How does arteriolar dilation affect fluid filtration in the capillaries?
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filtration becomes more prominent than absorption because hydraulic pressure increases
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How does arteriolar constriction affect fluid filtration in the capillaries?
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absorption becomes more prominent than filtration because hydraulic pressure decreases
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What are the 4 types of edema?
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-inflammatory edema (increased permeability of endothelium)
-venous edema (increased venous pressure) -hypoproteinemic edema (decreased plasma proteins) -lymphatic edema (lymphatic obstruction) |
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What type of heart failure causes systemic edema?
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right heart failure
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What type of heart failure causes pulmonary edema?
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left heart failure
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What are the functions of the lymphatic system?
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-returns excess interstitial fluid to the blood
-returns interstitial protein to the blood -transports cells (immune) -transports large molecules and debris |
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What factors contribute to circulation of lymph fluid?
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-pressure gradients
-one way valves -smooth muscle cells encircling lymphatics |
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What is filariasis?
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The parasitic worm Wuchereria bancroft forms nests in the lymphatic system, causing blockages. This results in edema.
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What does a p-value in statistical analysis indicate?
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large p-values in a comparison of two groups indicate that there is no difference between the two groups
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What is the difference between intent-to-treat analysis and treatment-received analysis?
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-intent-to-treat: analysis is done assuming that all subjects received their assigned treatment
-treatment-received: results are analyzed using the actual treatment received by the patient |
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What aspects of a treatment are best measured using treatment-received analysis?
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-efficacy of treatment
-analyzes therapy under ideal conditions |
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What aspects of a treatment are best measured using intent-to-treat analysis?
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-effectiveness of treatment
-analyzes therapy under real-life conditions |
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What is a double blind study?
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the following parties do not know what treatment group a subject has been assigned:
-subject -personnel administering the treatment -personnel assessing the outcomes/endpoints |
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What is a triple blind study?
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the following parties do not know what treatment group a subject has been assigned:
-subject -personnel administering the treatment -personnel assessing the outcomes/endpoints -personnel analyzing the study (statistician) |
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What is a Type I/α-error in statistical analysis? How is it identified?
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-the result being due to chance
-present when the p-values are > 0.001 |
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What is a Type II/β-error in statistical analysis?
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sample size is too small to detect true differences
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What are the types of pleurae that encase the lungs?
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-visceral (inner) pleura
-parietal (outer) pleura: cervical costal diaphragmatic mediastinal |
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How does the innervation of visceral and parietal pleura differ?
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-visceral: supplied by autonomic nervous system (no pain)
-parietal: supplied by somatic nervous system (pain) → intercostal and phrenic nerves |
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What part of the parietal pleura is supplied by the intercostal nerves?
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costal
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What parts of the parietal pleura are supplied by the phrenic nerves?
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-diaphragmatic
-mediastinal |
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What is pneumothorax? What causes it?
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-collapse of the lung and separation of the two pleurae
-caused by introduction of air into pleural cavity |
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What is tension pneumothorax?
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pressure increase in the pleural cavity with a punctured lung causes mediastinal contents to be shifted to the other side, applying pressure to it
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Where is the apex of the lung with respect to the ribs?
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above the level of the 1st rib
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Where do the oblique fissures begin and end with respect to the lungs and ribs?
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-begin at the posterior medial edge of the lung at the level of the base of the scapular spine
-end at the inferior border of the lung at costochondral junction of the 6th rib |
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The horizontal fissure meets the anterior border of the right lung at the level of which rib?
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rib 4
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The midclavicular line intersects the bottom of the lung at the level of which rib?
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rib 6
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The midaxillary line intersects the bottom of the lung at the level of which rib?
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rib 8
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The scapular line intersects the bottom of the lung at the level of which rib?
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rib 10
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The midclavicular line intersects the bottom of the parietal pleura at the level of which rib?
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rib 8
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The midaxillary line intersects the bottom of the parietal pleura at the level of which rib?
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rib 10
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The scapular line intersects the bottom of the parietal pleura at the level of which rib?
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rib 12
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How would injury to the phrenic nerve affect breathing?
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The affected side of the diaphragm would be paralyzed.
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How does the shape of the thoracic cage change with deep breathing?
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-upper ribs: increase the anteroposterior dimension
-lower ribs: increase the transverse dimension |
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What grooves/impressions are present in the left lung and not in the right?
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-brachiocephalic vein groove
-aortic impression -cardiac notch |
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Where is the trachea with respect to the esophagus? Where does it bifurcate with respect to the spinal cord?
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-the trachea is anterior to the esophagus
-it bifurcates at the level of T4-T5 |
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From what structure do the pulmonary arteries arise? What is their purpose?
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-pulmonary tract
-convey poorly oxygenated blood to the lungs |
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What is the mean pulmonary arterial pressure?
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15 mmHg
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Into what structure do pulmonary veins drain? What is their function?
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-left atrium
-convey well oxygenated blood from the lungs |
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From what structures do bronchial arteries arise? What is their function?
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-thoracic aorta
-posterior intercostal arteries (right) -right bronchial artery may arise from the left -carry well oxygenated blood to supply walls of bronchi and pleura |
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Into what structure do bronchial veins drain? What is their function?
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-azygos vein (right)
-accessory hemiazygos vein (left) -carry poorly oxygenated blood from the lungs |
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What is the superficial (subpleural) lymphatic plexus? To where does it drain?
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-drains the surface of visceral pleura
-drains to bronchopulmonary (hilar) nodes |
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What is the deep lymphatic plexus? To where does it drain?
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-follows the bronchi and pulmonary vessels
-drains to bronchopulmonary (hilar) nodes |
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What are the tracheobronchial lymph nodes? To where do they drain?
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-drain the bronchopulmonary (hilar) lymph nodes
-drain into paratracheal nodes |
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To where do paratracheal lymph nodes drain?
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-bronchomediastinal trunk → subclavian veins
-thoracic duct (left side) |
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Which pulmonary lobes are drained by the left paratracheal lymph nodes? Which are drained by the right?
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-left: drain left superior lobe
-right: drain right lung, left inferior lobe |
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What is the effect of efferent vagal stimulation on the lungs?
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bronchoconstriction
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What is the effect of afferent vagal stimulation on the lungs?
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-cough reflex
-stretch reception -vasodilation |
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What is the effect of efferent sympathetic stimulation on the lungs?
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-bronchodilation
-vasoconstriction |
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What is the effect of afferent sympathetic stimulation on the lungs?
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none
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Which ganglia supply the lungs with sympathetic stimulation?
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upper four thoracic ganglia
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What is the pulmonary edema safety factor?
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pressure difference between the capillaries and alveoli assures that absorption > filtration along the length of the pulmonary capillaries → water is always absorbed from the lung
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What effect do inotropic drugs have on left ventricle performance?
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increase stroke volume and cardiac output
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What effect do vasodilators have on left ventricle performance?
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-decrease left ventricle end-diastolic pressure
-increase stroke volume and cardiac output |
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What effect do diuretics have on left ventricle performance?
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decrease left ventricle end-diastolic pressure
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What is the difference between vascular response to hypoxia in the systemic tissues vs. the lungs?
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-systemic tissues: hypoxia/ischemia → vasodilation
-lungs: hypoxia → vasoconstriction |
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What is the sequence of events that occur with High Altitude Pulmonary Edema?
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-pulmonary hypoxic vasoconstriction
-pulmonary hypertension -pulmonary edema -impaired gas exchange -positive feedback loop |
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What is the foramen ovale? What happens to it following birth?
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-shunt which allows highly oxygenated blood to enter the left atrium from the right atrium
-often sealed in the first year following birth as a result of left atrium pressure rising above right atrium pressure |
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What is the ductus arteriosus? What happens to it following birth?
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-shunt which allows blood to enter the aorta from the right ventricle
-"functional closure" in 1-8 days following birth due to pulmonary artery pressure dropping below aortic pressure -"anatomical closure" in 1-4 months following birth |
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What is Patent Ductus Arteriosus?
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-failure of the ductus arteriosus to seal
-leads to pulmonary hypertension |
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How do systemic vascular resistance and arterial pressure change with birth? Why?
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2-fold increase, due to increase in blood flow from the lungs to left ventricle
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How does pulmonary vascular resistance change with birth? Why?
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10-fold decrease, caused by inflation of lungs and removal of fluid by coughing
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What is the ductus venosus?
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-connects umbilical vein to the inferior vena cava
-carries highly oxygenated blood -allows bypass of the fetal liver |
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How do the right and left ventricles change following birth? What is the electrical manifestation of this change?
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-right ventricle atrophies
-left ventricle hypertrophies -electrical axis of the heart swings to the left |
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Does gravity have a greater effect on venous or arterial pressure? Why?
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-venous pressure
-because the veins are distensible |
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What is the effect of arising on mean arterial pressure and central venous pressure?
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small transient decrease (due to gravity)
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What is the effect of arising on heart rate?
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30% increase (as compensation)
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What is the effect of arising on stroke volume?
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40% decrease (Frank-Starling mechanism)
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What is the effect of arising on cardiac output?
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25% decrease (combination of changes in heart rate and stroke volume)
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What is the effect of arising on systemic vascular resistance?
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increases (as compensation)
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What is the effect of arising on splanchnic, renal, and leg flow?
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25% decrease (as compensation)
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What is the effect of arising on venous tone?
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increases (as compensation)
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What is the effect of arising on central blood volume?
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400 mL decrease
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What is the effect of arising on blood volume in legs?
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600 mL increase
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What is the cause of the increase in heart rate to 100 beats/min in response to exercise?
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withdrawal of vagal tone
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What is the cause of the increase in heart rate to 100-200 beats/min in response to exercise?
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sympathetic augmentation
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Why are athletes able to perform relatively more exercise at a given heart rate?
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larger stroke volume
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Why does arterial pressure remain relatively stable during exercise, in comparison with cardiac output increase?
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systemic vascular resistance decreases with exercise
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What is the sequence of events that leads to cardiogenic shock?
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-myocardial failure
- ↓cardiac output - ↓arterial pressure |
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What is the sequence of events that leads to hemorrhagic shock?
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-blood loss
- ↓central venous pressure - ↓cardiac output - ↓arterial pressure |
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What is the sequence of events that leads to anaphylactic (septic) shock?
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-vasodilator release
- ↓systemic vascular resistance - ↓arterial pressure |
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What is the sequence of events that leads to neurogenic shock?
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- ↓sympathetic drive
- ↓systemic vascular resistance - ↓arterial pressure |
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How does the brain respond to shock (short-term)?
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-cerebral ischemic response (below 60 mmHg)
- ↓parasympathetic activity - ↑sympathetic activity |
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How does the heart respond to shock (short-term)?
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- ↑heart rate
- ↑contractility - ↑cardiac output |
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How does the vasculature respond to shock (short-term)?
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- ↑vaso/venoconstriction
- ↑systemic vascular resistance - ↓capillary pressure → transcapillary fluid absorption |
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How are the kidneys affected by shock?
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-sympathetic augmentation (from brainstem)
- ↓renal perfusion (from ↓systemic vascular resistance) |
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How do the kidneys respond to shock (long-term)?
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-RAA pathway
- ↓glomerular filtration - ↓urine output - ↑thirst - ↑central venous pressure |
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How long can the brain and heart be deprived of blood flow before experiencing irreversible ischemic damage?
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2-5 min
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How long can the kidney, lungs, and liver be deprived of blood flow before experiencing irreversible ischemic damage?
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120-180 min
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How long can the skeletal muscle, gut, and skin be deprived of blood flow before experiencing irreversible ischemic damage?
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360-600 min
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By what mechanisms is blood volume restored after hemorrhage?
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-transcapillary refill
-renal fluid conservation -thirst + sodium appetite |
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What are the decompensatory mechanisms in shock?
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-intense sympathetic vasoconstriction
-ischemia of organs -metabolic vasodilators override sympathetic input - ↓mean arterial pressure -positive feedback loop |