The neural system provides an organised network of point-to-point connections for a quick coordination between various
Central neural system (CNS) : Hollow, dorsally placed structure lying along the mid-dorsal axis of the body.
It comprises of:
(a) Brain (b) Spinal cord
(i) Peripheral neural system (PNS) : The nerves arising from CNS constitute PNS. It consists of:
(a) Somatic neural system
(b) Autonomic neural system
Parasympathetic neural system
Sympathetic neural system
Neurons.
The basic unit of the neural system is the individual ne cell, or neuron.
Neurons operate by generating electrical signals that move from one part of the cell to another part of the same cell
or to neighbouring cells.
Certain neurons may almost equal the length of the body itself. Thus, neurons with longer processes (projections) are the longest cells in the body. Human neural system has about 100 billion neurons. Majority of the neurons occur
in the brain.
The neurons detect and receive information from different sense organs (receptors) in the form of stimuli and transmit the stimuli to the central nervous system through sensory nerve fibres.
Neurones are many types, describe in next page.
