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what is the structure of a nerve cell? different parts and their functions.

A neuron is a nerve cell that is the basic building block of the nervous system.Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body  The primary function of the nerve cells of the body is communication. This is accomplished by passing electrical and/or chemical messages from neuron to neuron, or from neuron to other target cells.
There are three basic parts of a neuron: the dendrites, the cell body and the axon. However, all neurons vary somewhat in size, shape, and characteristics depending on the function and role of the neuron. Some neurons have few dendritic branches, while others are highly branched in order to receive a great deal of information. Some neurons have short axons, while others can be quite long..The cell body (also called the soma or perikaryon) of the neuron contains the nucleus which often has a prominent nucleolus . Spreading out from the cell body are long projections: the dendrites and axons.
 Dendrites carry electrical impulses towards the cell body, while axons carry electrical messages away from the cell body. Where the axon joins the cell body, there is a region call the axon hillock which is important in producing action potentials. The cell body usually contains abundant rough endoplasmic reticulum, which in the neuron is called Nissl substance.

The dendrites of neurons receive information from sensory receptors or other neurons. This information is then passed down to the cell body and on to the axon. Once the information as arrived at the axon, it travels down the length of the axon in the form of an electrical signal known as an action potential.
Once an electrical impulse has reached the end of an axon, the information must be transmitted across the synaptic gap to the dendrites of the adjoining neuron.
Neurotransmitters are needed to send the information from one neuron to the next. Neurotransmitters are chemical messengers that are released from the axon terminals to cross the synaptic gap and reach the receptor sites of other neurons. In a process known as re uptake, these neurotransmitters attach to the receptor site and are reabsorbed by the neuron to be reused.
Neurotransmitters are an essential part of our everyday functioning. While it is not known exactly how many neurotransmitters exist, scientists have identified more than 100 of these chemical messengers. Some of them are Acetyl choline,Endorphins,Dopamine etc.


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