<prompt> In tetany hyperexcitability is due to:Low Ca causes permeability to NaPrevent k releasePrevent Na K releaseCa produce generation of AP  <response>: Ans. a Low Ca causes permeability to NaRef: Ganong, 25th edp.380Reason for hyperexcitability in tetany - low serum calcium levels moves more sodium ions entry into the cell leading to more frequent action potential generation 