10 Nervous Tissue

  • Nervous tissue is a tissue which is specialized for being stimulated and transmission of messages within our body.
  • It exerts control over the body’s responses to changing conditions.
  • Nervous tissue contains highly specialised unit cells called nerve cells or neurons.
  • An individual nerve cell may be up to a metre long.
  • The brain, spinal cord and nerves are all composed of the nervous tissue.
  • Neurons are excitable cells that are the units of the neural system.
  • It is comprised of specialized cells which receive stimuli and conduct the impulses to and from different parts of the body.
  • Each neuron has following three parts:
    • The cyton- cell body which contains a central nucleus and cytoplasm with characteristic deeply stained particles,
    • The dendrons- which are short processes arising from the cyton and further branching into dendrites;
    • The axon- which is a single, long cylindrical process of uniform diameter.

How Neuron works?

  • The cell body contains a distinct nucleus and has a special kind of granules, called Nissel’s granules in the cytoplasm.
  • From the cell body a single long part called the axon and many branched parts called dendrites arise.
  • In some nerve cells the axon has a thick white covering called medullary sheath.
  • The terminal end of axon is without sheath and branched.
  • Each nerve cell receives message through the dendrites and sends them to the axon.


  • The dendrites receive impulses and the axon takes impulses away from the cell body.

Difference between axon and dendrite:

Axon Dendrite
It is long uniformly thickened fibre-like process of a neuron. It is a short tapering process of a neuron.
It is always covered with a sheath (e.g, medullary sheath).

A sheath is absent.

Nissl’s granules are absent. Neurofibrils are, however, present. Both Nissl’s granules and Neurofibrils are, present.
It carries impulses away from the cell body. It carries impulses towards the cell body.

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