Spinal Cord:

The spinal  cord extends downwards from the  brain stem through the  protecting bony rings called vertebrae down the  centre of  the backbone, to the bottom of the back.  Its core is H-shaped in cross  section and is composed of  several kinds of neurons. The sumding  mattez  is mostly long cables of axon fibres. The cord, too, is cwered  like the brain with thne  membranes and contains fluid between the membranes. 'there are 31  pairs of spinal nerves, that branch off from the spinal cord throughout its length, between the bones of  the spine. These nerves carry sensory signals upto the brain and motor signals down from the brain to various parts of  the body.