Human Neural System: Central and Peripheral Neural System Overview
Biology · Neural Control and Coordination · NEET
The human neural system is divided into two parts: the central neural system (CNS), which is the brain and the spinal cord, and the peripheral neural system (PNS), which is all the nerves of the body. The CNS is the control and processing centre; the PNS is the wiring that carries messages to and from the CNS. Memory hook: CNS = "Command Station" (brain + spinal cord); PNS = "Postal Nerves" that deliver in both directions.
The human neural system splits into the CNS (brain + spinal cord) and the PNS (all nerves). PNS fibres are afferent (into CNS) and efferent (out of CNS), and the PNS divides into somatic and autonomic systems.
Your doubts, answered
Is the spinal cord part of the CNS or the PNS?
The spinal cord is part of the CNS. NCERT is direct: the CNS includes the brain AND the spinal cord. Many students wrongly put the spinal cord in the PNS because it runs down the body. Remember only two structures are CNS: brain and spinal cord. Everything else (all nerves) is PNS.
What is the exact difference between CNS and PNS?
The CNS (brain + spinal cord) is the site of information processing and control. The PNS is all the nerves of the body that are connected to the CNS. So CNS = the thinker and decider; PNS = the cables that bring information in and carry commands out.
What do afferent and efferent nerve fibres mean here?
The PNS nerve fibres are of two types. Afferent fibres carry impulses FROM tissues/organs TO the CNS (input). Efferent fibres carry regulatory impulses FROM the CNS TO the organs (output). Memory trick: Afferent = Arriving at CNS; Efferent = Exiting the CNS.
Is the autonomic nervous system part of the CNS or PNS?
It is part of the PNS. The PNS is divided into the somatic neural system and the autonomic neural system. Somatic relays impulses from the CNS to skeletal (voluntary) muscles; autonomic sends impulses to involuntary organs and smooth muscles. The autonomic system is further split into sympathetic and parasympathetic.
Are the meninges (dura, arachnoid, pia mater) part of the CNS?
They are protective coverings of the brain and spinal cord, so they are associated with the CNS. NEET has asked which structure is NOT part of the central neural system, listing arachnoid, dura mater, pia mater (all CNS-related) versus pericardium (the sac around the heart, NOT neural). Do not confuse pericardium with a meninx.
⚠️ The NEET trap ✗ The peripheral neural system (PNS) includes the spinal cord because it extends outward from the brain. ✓ The spinal cord is part of the CNS. The PNS is only the nerves of the body that connect to the CNS. 🧠 Only two things are CNS: brain and spinal cord. If a question puts the spinal cord in the PNS, it is wrong. Also, meninges (dura, arachnoid, pia) protect the CNS, but the pericardium is around the heart, not neural.
Real NEET questions
ReNEET 2026
Which of the following is not a part of the human central neural system?
A · Arachnoid
B · Dura mater
C · Pia mater
D · Pericardium ✓
Solution: Arachnoid, dura mater and pia mater are the three meninges that cover and protect the brain and spinal cord (the CNS). The pericardium is the double-walled membranous sac around the heart, not part of the neural system. So pericardium is the odd one out.
Solved Neural Control and Coordination NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
What are the two parts of the human neural system?
The central neural system (CNS) and the peripheral neural system (PNS). The CNS is the brain and spinal cord; the PNS is all the nerves connected to the CNS.
Which organs make up the CNS?
Only two: the brain and the spinal cord. Together they process information and control the body.
What does the PNS contain?
The PNS contains all the nerves of the body linked to the CNS. Its fibres are afferent (into the CNS) and efferent (out of the CNS), and it is divided into the somatic and autonomic neural systems.
Why is this overview important for NEET?
NEET regularly asks which structures belong to the CNS or PNS and the afferent/efferent direction. Getting this basic map right lets you quickly rule out wrong options in one-mark questions.
