Class 11 Biology Chapter 18 Neural Control and Coordination – Revision Notes

Quick revision notes for Class 11 Biology Chapter 18 (Neural Control and Coordination). These Class 11 Biology Chapter 18 notes are ideal for quick revision just before exams.

Neuron and Impulse

• Cell body, dendrites, axon.
• Resting potential (~−70mV); depolarization (Na⁺ in) → repolarization (K⁺ out).

Synapse

• Chemical synapse: neurotransmitter (e.g. acetylcholine) crosses synaptic cleft.

CNS and PNS

• CNS: brain (cerebrum, cerebellum, medulla) + spinal cord.
• PNS: somatic (voluntary) + autonomic (sympathetic/parasympathetic).

Reflex Arc

• Receptor → sensory neuron → spinal cord relay → motor neuron → effector; faster than voluntary response.

One-Line Summary

The nervous system controls and coordinates body functions through electrical nerve impulses (action potentials) and chemical synaptic transmission, with the CNS, PNS, and reflex arcs enabling both voluntary and rapid involuntary responses.

Written by Satish

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