INTRODUCTION (Introduction): ORGANIZATION OF NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM SYMPATHETIC (Sympathetic) PARASYMPATHETIC (parasympathetic) NEURONE (neurons): The brain contains a large number (100 billion) of neurons is. Each neuron has the following characteristics Cell Body And Its Process Axone Dendrites (Dendrites) Some thread-like nerve fibers may also be present. Cell Body: Axone and Dendrites :- Structure of Axon: Dendrites: SYNAPSE AND NEUROTRANSMITTERS: NERVES