Pg.no. 15
Figure 4.2 (CNS and PNS)
Central nervous system (CNS) includes:
Brain or encephalon, which occupies cranial cavity, and contains the higher
governing centers.
Spinal cord or spinal medulla, which occupies upper two-thirds of the vertebral
canal, and contains many reflex centers.
Peripheral nervous system (PNS) includes:
Cerebrospinal nervous system is the somatic component of the peripheral nervous
system, which includes 12 pairs of cranial nerves and 31pairs of spinal nerves. It
innervates the somatic structures of the head and neck, limbs and body wall, and
mediates somatic sensory and motor functions.
Peripheral autonomic nervous system is the visceral component of the peripheral
nervous system, which includes the visceral or splanchnic nerves that are connected
to the CNS through the somatic nerves. It innervates the viscera, glands, blood
vessels and non-striated muscles, and mediates the visceral functions.