The `INa.cellml <../components/INa.cellml>`_ defines `the equation of the sodium current <../components/INa.cellml/cellml_math>`_.
It instantiates the imported `gating kinetics component <../components/gating-variable.cellml/view>`_ for m and h gates, while the gate rates are defined in `INa-gating-rates.cellml <../components/INa-gating-rates.cellml>`_.