We’ve just described the cell’s Plasma Membrane (PM) and how it separates the water inside a cell from the water outside a cell. But no man cell is an island. Except pancreatic islet cells, which is a joke we won’t cover until A&P 2.
We all know that the body is filled with water. And that cells are filled with water. So, how do you separate the water inside a cell from the water outside of a cell? It all starts with the Plasma Membrane or PM.