What is the primary function of neurotransmitters in the nervous system?

Neurotransmitters serve the primary function of transmitting signals between neurons. They are chemical messengers released from the synaptic terminals of one neuron, crossing the synaptic gap to bind to receptor sites on the next neuron. This process allows for communication throughout the nervous system, enabling the coordination of various bodily functions and responses. When an action potential reaches the end of a neuron, neurotransmitters are released, facilitating the continued propagation of the signal and ultimately leading to effects such as muscle contraction or the generation of a new action potential in the receiving neuron. This essential function underlines the role neurotransmitters play in everything from reflexes to complex behaviors.

The other options present functions that, while important in the broader context of biology, do not accurately describe the primary role of neurotransmitters. For instance, the storage of energy within cells is managed by molecules like ATP and glycogen, not by neurotransmitters. Creating sensory perceptions is a result of complex interactions involving multiple systems and not solely dependent on neurotransmitters. Regulating heart rate involves neurotransmitters but encompasses a wider array of processes within the autonomic nervous system.