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Nerve Cell

We all respond to the external stimulations. We withdraw our hands if we came in contact with the hot substances. Even a single celled amoeba, if poked with a fine glass needle, it responds to stimulation by withdrawing its pseudopodia. This reaction is caused by our nerve cells.

A human body is made up f number of cells. A nerve cell is defined as the cells of nervous system, which controls all types of body activities. The nerve cells are specialized cells, which transmits message from one part to another part of the body. All cellular organisms have evolved a coordinating system by which messages can be received and transmitted very rapidly to organs, enabling them to respond to an environmental change. The system which is responsible for this process is called as nervous system. The functional units of nervous system are nerve cell.

Nerve Cell Diagram

Nerve Cell

 

Types of Nerve Cells

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Nerve cells are classified based on the type of the message they transmits

  • Sensory nerve cell - The nerve cell that transfer the information about stimuli such as light, heat or chemicals from both inside and outside of our body to our central nervous system.
  • Motor nerve cell 0- The nerve cell that passes the instructions from our central nervous system to other parts of our body. For example – to  muscles or to our  glands
  • Association nerve cell- The nerve cell, which connects to our sensory and motor neurons.


Nerve Cell Function

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  • Communication and coordination,
  • Sensory nerves, which carries the message to brain.
  • Allows us to react to a stimulus.
  • They conduct electrical impulses away from the neuron's cell body.
  • It carries messages from other neurons to a cell body.
A receptor cell receives the stimulus and this generates electrical activity in a neighboring nerve cell. The afferent or sensory neuron conducts a specific effector system, which may be a muscle or a gland.

Nerve Cell Structure

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The shape and the sizes of the nerve cells vary as they are small, big and thus the size keeps on varying. Compare to other cells in our body, the nerve cells also have quite similar structures like - cell membrane, nucleus, mitochondria, ribosome and endoplasmic reticulum.

Structure of Nerve Cells

Nerve Cell Parts and Functions

Dendrites - A branching fibers with a surface lined with synaptic receptors, which is responsible for receiving the information from other neurons. It also collects and stores all incoming information from axon terminals.

Axon - It carries the  impulses away from the cell.

Soma - It contains the nucleus, mitochondria, ribosome, and other structures found in nerve cells. It is also responsible for the metabolic work of the neuron.

Presynaptic Terminals - They are the end points of an axon, which is responsible for releasing chemicals to communicate with other neurons.
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