Homework _6 Questions - Homework#6 Loegering Circulation...

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Loegering Circulation Computer lab and Cardiovascular Animal lab homework Circulation Computer Lab. Effect of sympathetic and parasympathetic tone on heart rate. 1. The heart rate increased above normal when both sympathetic and parasympathetic tone were decreased to zero because A. the SA node was generating action potentials at its intrinsic rate which is higher than the normal resting heart rate. B. without autonomic input, the AV node became the pacemaker of the heart. C. circulating epinephrine was activating beta-1 adrenergic receptors in the SA node. D. voltage gated ion channels were not functioning with the loss of acetylcholine. E. cardiac output increased 2. When parasympathetic tone was decreased to zero and sympathetic tone was normal, the heart rate increased above the intrinsic rate because A. there was an increase in the conduction velocity of cardiac action potentials. B. removal of normal parasympathetic tone caused an increase in cardiac inotropic state. C. removal of normal parasympathetic tone allowed the full effect of the sympathetic tone to be expressed. D. there was an increase in permeability to potassium in the SA node fibers. E. the decrease in parasympathetic activity caused an increase in sympathetic activity. Effect of heart rate on stroke volume and cardiac output 3. When the heart rate was increased from 40 to 120 beats per minute while holding sympathetic and parasympathetic tone constant, the decrease in stroke volume was due to A. a decrease in venous compliance. B. a decrease in preload. C. a decrease in afterload. D. an increase in left atrial pressure. E. a decrease in cardiac inotropic state. 4. When the heart rate was increased from 120 to 160 beats per minute, cardiac output decreased because A. myocardial contractions were beginning to summate. B. arterial pressure decreased and systemic vascular resistance was held constant. C.
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Homework _6 Questions - Homework#6 Loegering Circulation...

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