What are the functions and differences between axons and dendrites?
This reference is a bit basic, but lists the functions and differences between axons and dendrites.  Specifically, dendrites receive signals from other neurons, to the cell body; whereas, axons take signals away from the cell body (essentially 'input-output').  A diagram of the parts and the processes is below:



(Image source with additional information)

This Youtube tutorial is a nice visual description of both, and how they function within a neuron.