Conceptual cardiovascular, respiratory, endocrine, GI, and muscle physiology mechanisms tested on USMLE Step 1, separate from the equations cloze deck.
39 cards · basic cards · AI-written, checked twice. Edit anything.
- What mechanism describes increased venous return leading to increased stroke volume?
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The Frank-Starling mechanism- What is the physiological basis of the Frank-Starling mechanism?
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Increased sarcomere stretch increases actin-myosin cross-bridge formation- Where are arterial baroreceptors located?
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Carotid sinus and aortic arch- How does the baroreceptor reflex respond to a sudden rise in blood pressure?
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Increased parasympathetic and decreased sympathetic output, lowering heart rate and blood pressure- What effect does vagal (parasympathetic) stimulation have on the SA node?
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It decreases heart rate (negative chronotropy)- Which part of the cardiac conduction system has the fastest conduction velocity?
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Purkinje fibers- During which phase of the ventricular cardiac action potential does calcium influx sustain depolarization?
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Phase 2, the plateau phase- When during the cardiac cycle does most left ventricular coronary perfusion occur?
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During diastole- What causes the oxygen-hemoglobin dissociation curve to shift right?
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Increased CO2, increased H+ (decreased pH), increased temperature, and increased 2,3-BPG- What is the Bohr effect?
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Increased CO2 and H+ decrease hemoglobin's affinity for oxygen, promoting oxygen unloading at tissues- What is the Haldane effect?
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Oxygenation of hemoglobin in the lungs promotes release of CO2- What is hypoxic pulmonary vasoconstriction?
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Local vasoconstriction in poorly ventilated lung regions that redirects blood flow to better-ventilated areas- What do central chemoreceptors in the medulla primarily respond to?
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Changes in CSF pH caused by CO2 diffusing across the blood-brain barrier- Where are peripheral chemoreceptors located?
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Carotid bodies and aortic bodies- What do peripheral chemoreceptors primarily detect?
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A significant drop in arterial PaO2
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