Which of the following describes neurons?

Neurons are specialized cells that are fundamental to the functioning of the nervous system. They are responsible for transmitting electrical and chemical signals throughout the body, enabling communication between different parts of the nervous systems, such as the brain, spinal cord, and peripheral nerves. Each neuron is equipped with structures that facilitate this communication, including dendrites, axons, and synapses, allowing them to process and relay information effectively.

The other options refer to different aspects of biological function. While some cells do provide structural support to the brain, as mentioned in one of the choices, these are glial cells rather than neurons. The option related to breaking down neurotransmitters refers to metabolic processes that occur after signaling has taken place, which is not a primary role of neurons. Additionally, the regulation of heartbeats is primarily managed by the cardiac conduction system and not directly by neurons. Thus, the description of individual cells responsible for nervous system functions accurately captures the role and importance of neurons within the broader context of human development and physiology.