posterior part
Lateral
horns
Rubrospinal
i think it`s lumbar
They prevent lateral movement of the spinal cord.
Is located within the spinal cord and contains unmyelinated fibers.
Lateral Spinothalamic
If you meant the 'brain' and spinal cord - it's the 'nervous system'
Afferent impulses enter the spinal cord from the posterior section. They may get processed by interneurons. And, in most cases they exit the spinal cord through the efferent neurons in the anterior section. The reason that they refer to this as being opposite sides has to do with what are called the 'horns' inside the spinal cord. The afferent impulses enter the dorsal horns in the back and the efferent impulses exit in the front, the anterior horns. This may be why your reference, your teacher, or a book, says that impulses enter and leave from opposite sides of the spinal cord.
Horns
grey matter
yes