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Hypocalcemia increases sodium influx by leak channels. Why does this elevate the resting membrane potential and increase excitability?

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  • $\begingroup$ Which cells are you talking about? Where did you obtain the information from? $\endgroup$ – AliceD Feb 6 '16 at 17:27
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Assuming the question is in respect to neurons..in a nutshell...resting membrane potential & excitability both depend upon sodium permeability which in turn depends on potential difference of the excitable cell....now as the sodium influx is increased the minimum voltage required to increase the conductance of sodium decreases far below its normal value...so for a small increase in membrane potential from the normal very negative level the sodium channel becomes activated elevating the resting membrane potential...

In fact, the calcium ion concentration needs to fall only 50% below normal level before spontaneous discharge of peripheral nerves occur giving rise to "tetany"...

Reference- Adapted from Guyton & Hall- Textbook of medical physiology (12E)

You can also refer to Berne & Levy's & Ganong's physiology book for further details

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