<unk>  are the<unk>  that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs.<unk>  relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing. The<unk>  emerge from the central nervous system above the level of the first vertebrae of the vertebral column. Each<unk> is paired and is present on both sides. There are conventionally twelve pairs of<unk> , which are described with Roman numerals I–XII. Some considered there to be thirteen pairs of<unk> , including<unk> zero. The numbering of the<unk>  is based on the order in which they emerge from the brain and brainstem, from front to back. The terminal<unk>  (0), olfactory<unk>  (I) and optic<unk>  (II) emerge from the cerebrum, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain. The<unk>  are considered components of the peripheral nervous system (PNS), although on a structural level the olfactory (I), optic (II), and trigeminal (V)<unk>  are more accurately considered part of the central nervous system <unk> S). The<unk>  are in contrast to spinal<unk> , which emerge from segments of the spinal cord.
Cranial nerves
Peripheral nervous system
Nervous system
Central nervous system
Autonomic nervous system
Integumentary system
Enteric nervous system
Somatosensory system