Lesson 3 of 11 · 6 min
Human neural system
NCERT §18.2
When the gun fired, the sound went in and a command came out to Meher's legs. One set of fibres carried news in; another carried orders out. Mapping those paths is the whole of this section.
The lesson in notes
In short
The human neural system has two parts: the central neural system (CNS) and the peripheral neural system (PNS).
The CNS is the brain and the spinal cord; it is where information is processed and control is exerted.
The PNS is all the nerves of the body that are connected to the CNS. Its nerve fibres are of two kinds: afferent and efferent.
Afferent fibres carry impulses from tissues and organs to the CNS; efferent fibres carry regulating impulses from the CNS out to the tissues and organs concerned.
The PNS has two divisions. The somatic neural system carries impulses from the CNS to skeletal muscles; the autonomic neural system carries impulses from the CNS to involuntary organs and smooth muscles.
The autonomic neural system is divided further into the sympathetic and the parasympathetic neural systems.
The visceral nervous system is the part of the PNS made of all the nerves, fibres, ganglia and plexuses that carry impulses from the CNS to the viscera and from the viscera back to the CNS.