Our visceral organs are innervated by the nerve fibres of
(i) somatic neural system
(ii) sympathetic neural system
(iii) parasympathetic neural system

The somatic neural system relays impulses from the CNS to skeletal muscles while the autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body. The autonomic neural system is further classified into sympathetic neural system and parasympathetic neural system. Most organs have dual innervation (sympathetic and parasympathetic).