Final answer:
The true statement about the vertebrate nervous system is that gray matter is composed of neuronal cell bodies, processes, and synaptic contacts. White matter contains myelinated axons, not unmyelinated tracts. Spinal nerves carry sensory and motor information between the spinal cord and the body.
Step-by-step explanation:
The vertebrate nervous system includes components such as the brain and spinal cord, which are part of the central nervous system (CNS), and the peripheral nervous system (PNS). Discerning the true statements about its structure is essential for understanding its function.
Gray matter, which is found in the central nervous system, consists mainly of neuronal cell bodies, including interneurons and motor neurons, as well as synaptic contacts. The gray matter is organized into a butterfly shape in the cross-section of the spinal cord and is crucial for processing and transmitting information. On the other hand, white matter primarily contains myelinated axons, which form tracts for the rapid transmission of nerve signals.
Cranial nerves connect the brain directly to various parts of the head and neck, while spinal nerves link the spinal cord to the body, facilitating both sensory and motor functions. The cerebral cortex is not part of the midbrain but encompasses the outer part of the brain, containing the frontal, parietal, temporal, and occipital lobes responsible for high-level functions. Therefore, the statement that "Gray matter is composed of intermingled neuronal cell bodies, processes, and synaptic contacts" is true about the vertebrate nervous system.