What is the role of myelin sheath?

Myelin sheath insulates the axon and allows saltatory conduction — nerve impulse jumps from one Node of Ranvier to the next, greatly increasing the speed of transmission compared to unmyelinated fibres.

What is the difference between CNS and PNS?

CNS (brain + spinal cord) processes information. PNS (cranial and spinal nerves) transmits information between CNS and rest of the body. PNS is further divided into somatic and autonomic nervous systems.

What happens during an action potential?

Na⁺ channels open → Na⁺ rushes in → membrane depolarises (−70 mV to +40 mV). Then K⁺ channels open → K⁺ rushes out → membrane repolarises. Na⁺/K⁺ pump restores original ion distribution.

Nervous System

Neural Control and Coordination • Class 11 Biology • NCERT • CBSE

Neuron: structural and functional unit. Resting potential −70 mV (more K⁺ inside). Action potential: depolarisation then repolarisation. CNS = brain + spinal cord. PNS = cranial and spinal nerves. Reflex arc: receptor → sensory → spinal cord → motor → effector.

Frequently Asked Questions

What is the role of myelin sheath?: Myelin sheath insulates the axon and allows saltatory conduction — nerve impulse jumps from one Node of Ranvier to the next, greatly increasing the speed of transmission compared to unmyelinated fibres.
What is the difference between CNS and PNS?: CNS (brain + spinal cord) processes information. PNS (cranial and spinal nerves) transmits information between CNS and rest of the body. PNS is further divided into somatic and autonomic nervous systems.
What happens during an action potential?: Na⁺ channels open → Na⁺ rushes in → membrane depolarises (−70 mV to +40 mV). Then K⁺ channels open → K⁺ rushes out → membrane repolarises. Na⁺/K⁺ pump restores original ion distribution.

Study With GyanAI

GyanAI's AI tutor can answer any question about this topic instantly. Try GyanAI free for step-by-step NCERT solutions aligned with the CBSE curriculum.