This is a passive current which allows for calcium entry into the cell via the apical cell membrane. **CaB** was introduced by `Luo Rudy 94 <https://models.physiomeproject.org/e/81>`_ as a current to maintain electroneutrality in their cardiac cell model. No exact match has been found for the proteins that may constitute this channel.

`Corresponding bond graph model. <https://models.physiomeproject.org/workspace/82a>`_

`Corresponding protein knowledge page. <https://models.physiomeproject.org/e/bf1>`_

Bond graph diagram
===================
.. figure:: exposure/BG_CaB_2.png
   :width: 75%
   :align: center
   :alt: BG_CaB