What is the functional and structural unit of the nervous system?

The neuron is recognized as the functional and structural unit of the nervous system primarily because it is the cell type responsible for transmitting information throughout the nervous system using electrochemical signals. Neurons are uniquely structured with distinct components: the cell body, dendrites, and axon, each fulfilling critical roles in communication.

Dendrites are the parts of the neuron that receive signals from other neurons, while the axon transmits these signals to other neurons or muscles. However, neither dendrites nor axons alone constitute the entire functional unit; they are parts of the neuron, which combines their functions.

Glial cells support and protect neurons but do not transmit nerve impulses themselves. They play several auxiliary roles, including providing structural support, facilitating communication, and maintaining homeostasis in the nervous system. Therefore, while they are essential for nervous system function, they do not represent the fundamental unit involved in signal transmission.

The combination of all these aspects highlights why the neuron, as a specialized cell, is the primary functional and structural component of the nervous system, making it the correct answer in this context.