Each living creature in this world has a BRAIN.. But our BRAIN is unique.. It gives us ability to understand,, imagine & express things verbally.. It controls our heart,, blood circulation,, body movement,, breathe etc.. Our BRAIN receives scattered information from our senses i..e.. eyes,, ears,, nose,, tongue & fingers / hands & gives the best possible result(s) after processing.. It lets us dream,, think,, reason,, express,, feel & so on..

Above mentioned functions / tasks are controlled & coordinated by an organ i..e.. our BRAIN,, which looks like an apricot,, weighing about 2% of our total body weight.. 

Our BRAIN constitutes a very complex,, integrated processing control system called Central Nervous System.. It control our conscious & unconscious activities..

There are about 100 billion neurons in our BRAIN.. Neurons amazingly gather & transmit electro-chemical signals,, like wires & gates in a computer system.. Neurons are of many sizes & shapes depending on the functions to be performed by them.. 

A Sensory Neuron (accepts signals from outer parts of our body & transfer them to Central Nervous System) on our fingertip extends the length of our arm,, while in BRAIN they are only few millimeters long,, have Dendrite body (branch like structures,, connected with multiple cells) by a long Axon (long projection along with the length of a cell) with a Cell Body (when cell body dies,, the neuron dies) in middle..

Our muscle movement are controlled by motor neurons (accepts input from Central Nervous System & transfer them to the outer parts of our body) have Cell Body at one end & Dendrites at the other.. Inter Neurons carry information between motor & sensory neurons..