The nervous tissue has two outstanding properties : excitability and conductivity.
(a) Excitability : It is the ability of the nerve cells and fibres to enter into an active state called the state of excitation in response to a stimulus. Excitation arises at the receptors on account of various stimuli such as light, temperature, chemical, electrical or pressure which constantly act on the organisms.
(b) Conductivity : The excitation does not remain at
the site of its origin. It is transmitted along nerve fibres. The transmission of excitation in a particular direction is called conductivity