Synaptic contact and nerve impulse. Representation of the transmission of a nerve impulse from neuron synapse A (top) to a dendritic button on neuron B (bottom). Vesicles release glutamate (green balls) which binds to the receptors (purple) that open the sodium channels and enable the Na+ (+) ions to enter the dendritic button of neuron B, thus creating an electrical current. The two pink elements are mitochondria.