show more I'm studying graded and action potential...my teacher says the graded potential originates in the dendrite (the sodium coming in) but that graded potentials summate in the axon hillock, forming an action potential (if threshold is reached) How does the graded potential from the dendrite reach the axon... show more I'm studying graded and action potential...my teacher says the graded potential originates in the dendrite (the sodium coming in) but that graded potentials summate in ...