what is neuron

importance of neuron part – 2

Myelinated nerve fibres are found in spinal and cranial nerves. Un-myelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath around the axon, and is commonly found in autonomous and the somatic neural systems.

  1. Define meristematic tissue.
  2. Where are the intercalary meristems located?
  3. What are the main functions of nervous tissue?
  4. Give example of some involuntary movements.
  5. Where are fats stored in our body?
  6. Write the difference b/w parenchyma and sclerenchyma.
  7. Write the function of ligament and tendon.
  8. How plant tissues are different from animal tissues? Write the difference in tabular form.
  9. Distinguish b/w blood and lymph.
  10. Differentiate b/w simple and complex tissue.

what is neuron

NEURON

Nerve cell is the unit of nervous system. A neuron is a microscopic structure composed of three major parts, namely, cell body, dendrites and axon. The cell body contains cytoplasm with typical cell organelles and certain granular bodies called Nissl’s granules. Short fibers which branch repeatedly and project out of the cell body also contain Nissl’s granules and are called dendrites. These fibers transmit impulses towards the cell body. The axon is a long fibre, the distal end of which is branched. Each branch terminates as a bulb-like structure called synaptic knob which possess synaptic vesicles containing chemicals called neurotransmitters. The axons transmit nerve impulses away from the cell body to a synapse or to a neuro-muscular junction.

  • Based on the number of axon and dendrites, the neurons are divided into three types, i.e., multipolar (with one axon and two or more dendrites; found in the cerebral cortex), bipolar (with one axon and one dendrite, found in the retina of eye) and unipolar (cell body with one axon only;found usually in the embryonic stage). There aretwo types of axons, namely, myelinated and non myelinated.