Chapter 2, End of Chapter, Review Questions, Exercise 1

According to neuron doctrine, cell theory applies to the neurons in the brain. The neuron doctrine states that the neurites (projection arising from the neuronal cell body) of different neurons communicate by contact, and certainly defines that neurons present in the nervous system are not continuous. The neuron doctrine is a widely accepted concept. It states that the nervous system is made up of individual neurons (specialized cells). Thus, the neurons form the basic functional unit of the nervous system.

Neurons are capable of communicating with each other through axons and dendrites, called the neurites. The neurites carry and transmit the nerve impulses to other neurons. The electrical impulses transmitted cause changes in the membrane potential of the neurons to which these impulses reach and act as signals for generating new impulses.

The neurons are supported and protected by the glial cells. Earlier, scientist Camillo Golgi stated that the neurites of different neurons are fused together to form a continuous network. According to him, cell theory which states that the basic unit of a tissue is a cell does not hold true for the brain. The conformation of the neural doctrine led to the conclusion that the discrete and independent cells adjoin to form the network within the nervous system.