Neuron and its types in detail

Basic functional units of nervous system


The structural and functional unit of nervous system is called neuron.


Neurons are specialized to generate signals. These signals can be communicated over a short or long distances. The can be sent from one part of an living organism body to another.

Properties of neurons

Neurons have two important properties

1. Excitability

The ability to respond to stimuli is called excitability.

2. Conductivity

The ability to conduct a signal is called conductivity.

Types of neurons

There are three basic types of neurons. These types are:

1. Sensory neurons

2. Inter-neurons

3. Motor neurons

1. Sensory neurons

The neuron which transmits nerve impulse from receptor to central nervous system (CNS) is called sensory neuron.


There are two types of sensory neurons

(a) Receptor sensory neuron

Some sensory neurons act as receptors. They receive stimuli directly. They are called receptor sensory neurons.

(b) Affect-er sensory neuron

Some sensory neurons are activated by receptors. They are termed as affect-er or afferent sensory neurons.

Changes in the internal or external environment stimulates sensory neurons. Sensory neurons transmits signals to integrating center. The information are processed in this center.

2. Inter neurons

The neurons which form the integrating center are called inter neurons.

They receive signals from the sensory neurons and transmit them to motor neurons.

3. Motor neurons

The neurons which transmit the nerve impulse to effectors are called motor neurons.

The effectors show response. Effectors may be muscles or glands.


Muscles show responses by contraction.


Glands show responses by secretions.

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