In the nervous system, bundles of fibres are called nerves.
The spinal nerve carries motor, sensory, and autonomic signals/information from the spinal cord to the brain and other part of the body.
The human body spinal cord consists of 4 regions, and 31 pairs of spinal nerves. The 31 pairs of spinal nerve are distributed one on each side of the vertebral column within the four regions of the spinal cord. The four regions of the spine are the cervical, thoracic, lumbar and sacral regions.
The mechanical layer lies above the core is the mantle. It is the layer that is found after the core and it is the second layer of the Earth . It is about 84% of the Earth’s volume.
