Page 9 ”In excitable cells, movement of ions across the plasma membrane results in changes of electrical potential across the membrane, and these potential changes are the primary signals that convey biological messages from one part of the cell to another part of the cell” Given that those messages are delived by ions, the conveyed biological messages also mean changes of concentration. After crossing the membrane, the ions (as slow currents) also physically move in the layer on the surface of the plasma membrane. To consider the process and the dynamically formed component is essential in understanding why and how APs form, as well as how those signals are processed and transmitted. Their effect is significant. As shown in Page 12, the total number of ions in the spherical cell is . As we estimate in section 3.5.1, the number of ions conveyed in a single signal is about , which seems to be negligible. However, the number of uncompensated ions is estimated, in line with our estimate for the order of number of ions per pulse, as , so it is absolutely necessary to consider the finite resources, as we do it in section 2.2.2. In line with our estimate, in the order of pulses in quick succession are needed to drastically change the number of ions (aka concentration or potential of the bulk) in the cell.