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physiology test

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Introduction

Why is an excess of KCl in the extracellular fluid of the body lethal A. It creates a big positive charge in the extracelular fluid. B. The high concentration of K+ outside cell membranes greatly hyperpolarizes cell membranes. C. It blocks the activity of the Na+,K+-dependent ATPase in cell membranes. D. It reduces the diffusion of K+ out of cells into the extracellular fluid. ????? ~~ of all the things iv lost i miss my mind the most~~ says: . It increases the concentration gradient of K+ across cell membranes. Moving to the next question prevents changes to this answer. ????? ~~ of all the things iv lost i miss my mind the most~~ says: How does an action potential 'travel' along an excitable membrane A. ...read more.

Middle

What could be changed to make a Cl- current depolarize the membrane A. Increase the normal concentration gradient for Cl- across the membrane. B. Increase the intracellular [Cl-] such that ECl is about -40 mV. C. Reduce the resting polarization of the membrane to abou ????? ~~ of all the things iv lost i miss my mind the most~~ says: E. Use a different neurotransmitter than GABA to bind to the Cl- ion channel ????? ~~ of all the things iv lost i miss my mind the most~~ says: D. Block the Cl- channels with a toxin or poison. ????? ~~ of all the things iv lost i miss my mind the most~~ says: C. Reduce the resting polarization of the membrane to about -60 mV ????? ...read more.

Conclusion

The afterhyperpolarization prevents excitation of the membrane. B. It takes many milliseconds to repolarize the membrane, especially if there are no voltage-gated K+ channels present. C. Because of depolarization block. D. The 'Na+ pump' requires several milliseconds to restore the Na+ concentration gra ????? ~~ of all the things iv lost i miss my mind the most~~ says: D. The 'Na+ pump' requires several milliseconds to restore the Na+ concentration gradient across the membrane. E. Na+ channels require time to restore their 'resting' configuration after the membrane potential repolarizes below threshold level. ????? ~~ of all the things iv lost i miss my mind the most~~ says: Opening a Cl- ion channel in the post-synaptic membrane normally holds the membrane at resting levels, around -70 mV. What could be changed to make a Cl- current depolarize the membrane ...read more.

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