What is nervous system and how it is important for human beings?
Introduction
Nervous system is the control and communication mechanism of body in which brain, spinal cord and their network combine to perform an action in which a human will capable to understand or analyze internal and external stimulus on the basis of that stimulus these network prepare body parts e.g glands and muscle to take action again them. For more about human bodyhttps://healthduhs.blogspot.com/2026/04/what-is-function-of-human-intestine.html
For example
When we touch hot objects that is harmful for us and cause damage to our skin if we don't keep away our touched body it might cause damage to internal organ and tissue even they cause death. For this purpose to prevent us from stimulus eitherly positive or negative nature has created nervous system when we exposed to hot object our body experienced it and send signal to brain there brain interpret this and send respond to muscle and gland to take action against them. In this case when the brain feel it dangerous and send signal to muscle to keep your body away from them and as per the command of brain and spinal cord muscle contract keep the side away from stimulus in this way they protect us as well as inform this is just an example its not enough about nervous system there are more than countable examples.
What is the composition of nervous system?
Nervous is a brought system which is made up of two type of cells.
1. Nerve cells
Nerve cells are those type of cell in nervous system which are responsible for transformation of message from one body part to another which act like the wire in electricity when we require to transfer electricity from one place to another then it will be our first choiese to spread a wire throughout the area thereafter it will be possible for us to submit electric current there such like that human nervous system perform their activity just like electric wire.
These nerve cells combine to form each other and make a biggest system which carry out a difficult activity.
What is the composition of neuron cell?
Neuron is made up of three parts
* Cell body
It is the part of neuron cell which contain
Neuclus
Control all the activities of neuron cell
Mitochondria
Responsible for energy production in neuron
Nissls body
Nissla body synthesis protein
* Dendrites
Projection from cell body which bring signal toward the cell
* Axon
Which bring away impulse from the cell to another cell
* Schwann cell
Special type of glia cell which synthesize mylein sheith around the axon
There are three types of neuron cells
1.Affarrent neuron
This is the type of neuron which bring nerve impulse toward central nervous system for interpretation.
2. Effarent neuron
This type of neuron is responsible for move away a response from central nervous system to effector of the body.
3. Inter neuron
It is another type of neuron which is present in central nervous system which is responsible for receive message from affarent neuron and send it to functional area for further
Analysis and after analysis in functional area send it to effarent neuron.
2. Glia cells
Gli cell or neuroglia cells are another type of nervous system but here their is a difference in which glia cell provide protection to the neuron cell and also provide neutrient like glucose and oxygen to neuron and also remove waste from their. Glia cells have better capability to regenrate them self properly but this ability lack in neuron. Second difference between neuron and glia cell is glia cell doesn't transfer electric signal.
The number of glia cell in human nervous system is 9time greater than the stars of our galaxy we can say its around 900billion.
What is the composition of glia cell?
It is made up of cell body called soma which contain nucleus and other organnels.
It lack dendrites and axon and contain projection which help in bind it together.
There are five types of glia cells.
1. Microglia
Microglia is the type of glia cell which found throughout the central nervous system brain and spinal cord Which is responsible for traping and removing foreign bodies in medical term they called phagocytosis. It is the vital function of miroglia in immunity.
2. Astrocytes
These are another type of glia cell that are found in central nervous system especially around capillary and neuron. They form a blood brain barrier and also provide neutrient to neuron.
The last important function of astrocytes, it is important in the repairing of central nervous system when any tissue of central nervous system damage astrocytes repair them this process is called geliosis.
But here is and important point the tissue of central nervous system repair physically but in functionally.
3. Schwann cells
It is an another type of glia cell which is present in prepheral nervous system around the axon of neuron which form mylein sheith around the neuron and the mylein sheith is responsible for speeding up the nervous signal.
Second function of schwann cell is it gives protection for axon and also remove debris and foreign particles. It also perform an importan role in the repairing of peripheral nervous system which guide axon to regrowth.
4. Ependymal cells
Type of glia cell found in the ventricle of brain and central canal of spinal cord.
In ventricle of brain they are found in choroid pluxes where they produce cerebro spinal fluid(CSF).
Such type of cell have cilia which are responsible for the movement of CSF through ventricle and spinal canal.
Last context about ependymal cell they form a linning which separate neuron from CSF.
5.Oligodendrocytes
This type of glia cell found in central nervous system brain and spinal cord which are responsible for the myleination of axon in central nervous system one oligodendrocytes can myleinate more than one axon at a time.
How neuron connect with each other?
It is an important topic that how neuron connect with each other, we have have discussed all the setructure of neuron now we will discuss about their connection.
We know that first affarent neuron connect with the receptor of body through their dendrites they convey message toward axon for the purpose of its forwarding to another neuron when the message or nerve impulse approach at the end of axon on the opposite site of axon the dendrites of another neuron is present there is a free space between both neuron that is called synaptic clift the neuron which bring message toward sinaptic clift is called presynaptic neuron and the neuron which receive that message is called post synaptic neuron. The process of delivering of nerve impulse from one neuron to another neuron is called synapsis.
How synapsis works?
When the message reach at the terminal end of presynaptic neuron at that time calcium gate open and calcium ions move inward when the concentration of calcium ions increase the movement of vessicles ( membraneous bound setructure which is filled with neurotransmitter )toward the membrane of presynaptic neuron
When this vessicle attached with the membrane of presynaptic neuron they release their neurotransmitter into synaptic clift.
On the another side there is post synaptic neuron which is responsible for receiving message their are special type of receptor are present on the membrane of that cell where the neurotransmitter will bind. After the binding of neurotransmitter on receptor there might be two events happen excitatory or inhibitory.
In excitatory phase after attachment of neurotransmitter Na gate open allow Na to inter into the cell this cause high concentration of positive ions inside membrane and again generate action potential.
In inhibitory phase after the attachement of neurotransmitter choloride gate open which allow choloride ions to inter that make another cell less capabale for next action potential and the cell become high concentration of negative ions. In this phase signal will not transfer to another neuron.
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