Final answer:
Gray matter contains neuron cell bodies and is where all synapses are located. It is responsible for the processing of muscle control, sensory perception, and other central nervous system functions.
Step-by-step explanation:
The responsibilities of muscle control, sensory perception such as seeing and hearing, memory, emotions, and speech are primarily associated with the functions of gray matter. Unlike the white matter, which consists chiefly of myelinated axons, gray matter contains neuron cell bodies, dendrites, and the unmyelinated axons of interneurons and motor neurons. The gray matter in both the brain and the spinal cord serves as the critical processing center where synapses are located and where neurotransmission occurs, facilitating communication within the central nervous system. Reflexes occur with rapidity due to local synaptic connections in the spinal column, involving the gray matter, which contains all synapses engaged in signal transmission along the brain and spinal cord.