To Understand The Structure Of A Nerve Cell [Neuron]

What Is An Axon?

• An Axon Is What Carries Information Or Responses Away From A Neuron.

What Is A Dendrite?

• A Dendrite Is What Carries Information Or Responses To A Neuron.

What Are Their Similarities And Their Differences?

1. An Axon Is Single In Number. ie. There is only one Axon to a Neuron, While A Dendrite Is Many in number, also known as Dendrites. 
2. An Axon Is Long And Travels A Long Way From The Neuron, While A Dendrite Divides Into Branches And Ends And Hence, Are considered Very Short. 
3. And The Final Difference Is Their Most Visible Difference An Axon Carries Information From The Neuron, While The Dendrites carry Information To The Dendrites.

Now You May Wonder Why and How Does a Neuron Receive And Send Information? The Answer Is Simple, There Is More Than One Type Of Neuron. And All The Types Are Involved In A Process. There Are Three Types Of Neurons, They Are:

1. Sensory Neuron
2. Motor Neuron
3. Relay Neuron

Now, Let's See How Each Of The Neurons Is Involved In A Simple Process Such as a Pin Pricking The Finger:

1. Receptor [SKIN] - TO -
2. SENSORY Neuron - TO -
3. RELAY Neuron - TO -
4. MOTOR Neuron - TO -
5. Effector [MUSCLE].

This Is The Same Way How Things Go About In A Reflex Action. But The Reflex Action Is:

• Involuntary
• Beyond The Control Of The Mind, Which Means That The Peripheral Nervous System That Is The Spinal Cord And The Spinal Nerves Send A Reaction Without Waiting For The Brain To Respond.
• Rapid
• Automatic

What Is Synapse [NeuroTransmitter] ?

• When Information Is Passed From One Neuron To The Other, They Do Not Touch Each Other. Instead, An Impulse Is Released From The Primary Neuron And It Trigger Off An Impulse In The Secondary Neuron. The Gap Which TRANSMITS The Impulse From The Primary Neuron And Triggers It In The Secondary Neuron, Is Called A Synapse Or A NeuroTransmitter.

What Are NeuroTransmitters ?

• NeuroTransmitters Are Chemicals Which Transmit Signals From A Neuron To A Target Cell Through A Synapse.

What Is A Chemical Synapse?

• A Chemical Synapse Are Specialised Junctions Through Which A Neuron Impulse Is Carried To another Or To Non-Neuron Cells Such As, Muscles Or Glands.

What Are Antagonistic Muscles? 

• These Are Muscles Found In Pairs Called Antagonistic Pairs. These Pairs Usually Consist Of An Extensor Muscle, Which OPENS the Joint ie. Increasing The Angle Between The Two Bones. And The Other Is The Flexor Muscle, Which Works Opposite The Extensor Muscle.
• The Main And The Most Visible Type Of Antagonistic Muscles Are The Biceps And The Triceps, ie. The Upper Arm.

Important Pointers To Remember

• The Brain And The Craneal Nerves Make Up The Main Nervous System.
• The Spinal Cord And The Spinal Nerves Make Up The Peripheral Nervous System.
• Craneal Nerves Are Associated With The Brain While The Spinal Nerves Are Associated With The Spinal Cord.