21.2 Human Neural System

• The CNS includes the brain and the spinal cord and is the site of information processing and control
• PNS comprises of all the nerves of the body associated with the CNS
• The afferent nerve fibre transmit impulses from tissues or organs to the CNS
• The efferent fibres transmits regulatory impulses from the CNS to the concerned peripheral tissues or organs
• The somatic neural system relays impulses from the CNS to skeletal muscles
• The autonomic neural system transmit impulses from the CNS to the involuntary organs and smooth muscles of the body
• The sympathetic nervous system prepares the body for action by increasing heart rate, blood pressure, respiration etc.
• The parasympathetic nervous system restores normal conditions when there is no need for emergency response
• Visceral nervous system is the part of the PNS that comprises the whole complex of nerves, fibres, ganglia and plexuses by which impulses travel from the CNS to the viscera and from viscera to the CNS