Final answer:
The spinal cord's ventral and dorsal roots are made up of motor and sensory neuron axons, respectively, while the rootlets are smaller strands that combine to form these roots. The ventricles, former parts of the neural tube, allow circulation of cerebrospinal fluid in the brain.
Step-by-step explanation:
The ventral roots and dorsal roots of the spinal cord play distinct roles in the central nervous system. The ventral (anterior) roots consist of axons emerging from the anterior or lateral horns of the spinal cord, which carry motor information to muscles and glands, whereas the dorsal (posterior) roots contain axons of sensory neurons that transmit sensory information from the periphery of the body to the spinal cord.
In contrast, the ventral rootlets and dorsal rootlets are the smaller strands that combine to form the individual dorsal and ventral roots, respectively. Each ventral rootlet comprises motor neuron axons, and each dorsal rootlet contains sensory neuron axons. The dorsal root ganglion is associated with the dorsal root, which houses the cell bodies of sensory neurons.
This anatomical division is crucial for the body's sensory and motor functions, as evident by the flow of cerebrospinal fluid in the ventricles, which were once part of the hollow center of the neural tube but now are spaces allowing cerebrospinal fluid to circulate through the brain.