Final answer:
The contents of the spinal lemniscus are composed of axons, which are part of the sensory neurons with cell bodies in the dorsal root ganglia. They are an essential component of the central nervous system, particularly the spinal cord, which also includes gray matter of neurons and white matter of myelinated axons.
Step-by-step explanation:
The contents of the spinal lemniscus are primarily composed of axons that carry sensory information. These axons belong to sensory neurons whose cell bodies are located in the dorsal root ganglia. This structure is a part of the central nervous system (CNS), which is composed of the brain and spinal cord. The spinal cord acts as a critical pathway for information traveling between the brain and the rest of the body.
The spinal cord itself is organized into gray matter, which includes the cell bodies of neurons and interneurons, and white matter, which contains the myelinated axons. These axons allow for the transmission of electrical signals that carry sensory and motor information.
The main divisions of the brain are the cerebrum, cerebellum, and brainstem, and the cerebrum itself is divided into four lobes: frontal, parietal, temporal, and occipital. Each lobe is responsible for different functions ranging from sensory perception to reasoning and motor control.