Carnial nerves :
1)The peripheral nervous system is the network of spinal (31 pairs) and cranial nerves (12 pairs) that are linked to the brain and spinal cord on one end and muscles to the other.
2) Cranial nerves or cerebral nerver that emerge directly from fore-brain and brain stem.
3) The brain receives information from each of the cranial nerve and issues controls the functions of various structures, primarily of head and neck.
4) Each of the cranial nerve is paired on the left and right in humans.
5) There are twelve pairs which are assigned roman numerals I to XII. An additional pair of cranial nerves termed cranial nerve zero (CN0).
6) The cranial nerves 0,I and I and II emerge from cerebrum, the remaining ten pairs emerge from the brain stem.
7) The ten cranial nerves and their functions are as follows.
Spinal Nerves :
1) The term spinal nerves generally refers to a mixed spinal nerve, which carries motor sensory and automatic signals between the spinal cord and the body.
2) Humans have left - right pairs of spinal nerves corresponding to the segment of vertebral column.
3) Outside the vertebral column the nerve divides into branches.
4) Spinal nerves take their origin from spinal cord. All of them are mixed nerves having both sensory and motor fibres.
5) The sensory fibres originate from the dorsal horn of the spinal cord. They carry information from organs to spinal cord.
6) The motor fibres take their origin from the ventral horns of the spinal cord. These supply information required for the movement of the muscles.
