http://en.wikipedia.org/wiki/Cell_junction

So I basically just wanted to mention how awesome and complicated and important cell communication was. That a billions of individual cells have to find a way to be self contained and yet still have lucid communication with eachother near and far. Which allows muscles to contract, electricity to go through our neurons, hormones to regulate our bodies, cells to divide or self destruct, cells to express certain genes, and billions of more processes. They do this on several different levels. They may use direct communication where charged molecules or proteins actually pass from one cell to another through cell junctions (connections). Or maybe they do this through signal transduction pathways which involve dozens of proteins and the signal attaches to a receptor on the surface of the membrane which causes it to change shape and then that causes a series of chain reactions inside of the cell carrying the signal. There are thousand and thousand different tranduction pathways! Many of which we don't know about. It is amazing....Check it out

http://learn.genetics.utah.edu/content/cells/insidestory/