What does gray matter primarily consist of?

Gray matter primarily consists of nerve cells (neurons) and dendrites. This is where synapses occur and where the integration of information takes place. In the central nervous system, gray matter is found in the brain's cortex and in various subcortical structures, playing a critical role in processing and relaying information to and from different parts of the brain and spinal cord.

The presence of neurons in gray matter is significant because these cells are responsible for processing sensory input, executing motor commands, and facilitating communication between different brain regions. Dendrites, which extend from neurons, are critical for receiving signals from other neurons, allowing for the complex interactions that underpin cognitive functions and responses.

The other choices refer to different components associated with nerve structures. Nerve fibers are found in white matter, where myelinated axons are present, facilitating faster communication across longer distances. Motor and sensory pathways encompass a broader network of both gray and white matter, making it an incomplete answer when focusing solely on what defines gray matter itself.