Equilibrium potential (K+, neuron)


The figure shows a neuron from an animal’s brain with the following labeled:

      potassium (K+) ion concentrations (measured in mM) inside and outside the animal neuron

      membrane potential (-70 mV)

      K+ channel


a) At rest, there is net movement of K+ ions out of the neuron through the K+ channel (as indicated by the arrow).  During an experiment, the animal begins experiencing depressed neurological function and falls into a coma.  A review of the data from the experiment indicates that these neurons were generating fewer action potentials than normal.  Also, K+ was moving INTO the neuron instead of out.


What could have changed to cause net movement of K+ INTO the neuron? Identify as many ways as you can.



b) Explain how the ways you identified above cause K+ to move INTO the neuron.



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This material is based upon work supported by the National Science Foundation (DUE grants: 1438739, 1323162, 1347740, 0736952 and 1022653). Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.