All actions of the nervous system depend on the transmission of nerve impulses over which of the following?

Neuroglia, or glial cells, serve supportive roles in the nervous system, such as providing structural support, insulation, and nourishment to neurons. While they are critical for the overall health and maintenance of the nervous system, they do not transmit nerve impulses themselves, which is the primary function of neurons.

Efferent pathways refer to the routes through which nerve impulses travel away from the central nervous system to effectors like muscles and glands. While they play a role in conveying signals, they are not the structures responsible for generating and transmitting the impulses; that role belongs to neurons.

Afferent pathways carry sensory information from the peripheral nervous system to the central nervous system. Similar to efferent pathways, they are important for signal transmission but do not originate or conduct the nerve impulses themselves, which are produced by neurons.