Final answer:
Neurotransmitters are the chemical signal molecules released by neurons that are essential for communication between neural cells.
Step-by-step explanation:
The chemical signal molecules released by neurons are called neurotransmitters. These molecules, once released from the neuron's synaptic end bulbs, traverse the synaptic gap to bind with receptors on the target cell's surface, thereby transmitting signals to the next cell.
This release occurs through vesicles via a process known as exocytosis, one extremely well-studied neurotransmitter being dopamine, with the chemical formula C8H11NO2. Dopamine plays a key role in numerous neurological processes and its dysfunctions are associated with diseases like Parkinson's and schizophrenia.