Subject: On a cellular level, how do humans grow?

The question is fairly simple, but the answer is complicated. I am doing a 
project on Acromegaly (gigantism), but first i want to understand how 
a 'normal' human grows, please feel free to include the GRowth hormone in your 
answer.  Please answer down to the cellular level, ie. what does the growth 
hormone do to the cell that makes the whole arm or leg get bigger.

Thank you very much, you guys are my last hope.

-neil

Re: On a cellular level, how do humans grow?