internal means its on the inside external means its on the outside
so an internal regulator is when the proteins respond to events on the inside of a cell and an external regulator is when the proteins respond to events outside the cell
The Difference Between How Internal & External Regulators Work. Internal and external regulators both work to determine the length of time from one cell division to the next. This interval is called the cell cycle. ... The cell membrane separates the interior of the cell from its outer environment.
