In a motor neuron, substances have to move across the membrane to ensure the correct functioning of the nervous system. How is the movement of Na+/K+...

Na+ and K+
ions move across the membrane of motor neurons by an enzyme called Na+/K+ATPase, found in the
plasma membrane of motor neurons and all other animal cells. Na+/K+ATPase consumes energy in the
form of ATP in order to move three sodium ions out of the call and two potassium ions into the
cell, resulting in a net export of a single positive charge per cycle of the enzyme.

Conversely, neurotransmitters are much larger and more complex molecules and they do
not pass through the cell membrane of the neuron at all. Instead, they are released into the
synaptic cleft from vesicles in the axon terminal of the initiating nerve cell. Then, they
attach to neuroreceptors on the dendrites of the receiving neuron. When a neurotransmitter binds
to the appropriate receptor, it triggers further changes within the cell.