Nervous system : Central & Peripheral nervous system

In this blog, we will learn about basic information of nervous system.There are many system working in our body like respiratory,cardiac,GIT,endocrine,etc. But nervous system is more complex and fastest working than others.

I am giving you example that how this system works.Suppose unknowingly you put your hand in hot water, within fraction of second you pull out.Why? This is because this system works.Hand gives message to brain and in return brain sends signal to pull out hand and we save our hand from burning.

As you can see image that there are two division :

• Central nervous system (CNS)
• Peripheral nervous system (PNS)

CENTRAL NERVOUS SYSTEM 

Here we learn some basic points of CNS.

1. CNS includes brain and spinal cord.It is formed by neurons and supporting cells called neurolgia.

2. Location 

   Brain is situated in the skull.It is continued as spinal cord in the vertebral canal through the foramen magnum of the skull bone.

3. Layers

   Brain and spinal cord are surrounded by three layers of meninges.You can remember this way that outer layer is durable so it’s called dura mater.Inner layer is Pia mater and middle layer is Arachnoid mater.

Space between middle layer arachnoid and inner layer Pia mater is known as subarachnoid space & it’s filled with cerebrospinal fluid(CSF).Brain and spinal cord are actually suspended in the CSF.

4. Parts of brain

   There are three parts of brain named as forebrain,midbrain,hind brain.

Forebrain 

Telencephalon 

cerebral hemispheres,basal ganglia,hippocampus,amydaloid nucleus.

Diencephalon 

thalamus, hypothalamus,metathalamus,subthalamus.

Midbrain 

it is particular point as you can see in image.

Hindbrain 

it contains Pons,cerebellum and medulla oblongata.

5. Grey and white matter 

   Brain and spinal cord arranged in two layers named as grey matter and white matter.

White colour of white matter is because it formed by axons and grey colour of grey matter is because it formed by nerve cell bodies and proximal part of nerve fibre.

When you dissect brain this way you will find grey matter is placed in outer part and white matter is placed in inner part of our brain.White matter is inside & grey matter is outside in brain.We just remember this situation.

In spinal cord this two matter location is changed in contrast,white matter is outside and grey matter is inside.But it will create confusion so just remember structure of matter in brain.

PERIPHERAL NERVOUS SYSTEM

As you can see in image that PNS is formed by neurons and their processes present in all region of the body.

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It contains cranial nerve arising from the brain and spinal nerve arising from the spinal cord.

It devided into two subdivisions.

1. Somatic nervous system
2. Autonomic nervous system

SOMATIC NERVOUS SYSTEM

It is voluntary means it’s in our control.When we need to do muscular activity and body movement, we need it.If you want to move your hand, you can do it with help of this system only.

AUTONOMIC NERVOUS SYSTEM

It is not voluntary means it is not in our control.It is involuntary system.On basis of involuntary activity it devided in two decision.

1. Sympathetic nervous system 
2. Parasympathetic nervous system

1. Sympathetic nervous system 

It is involuntary and it works for fight-flight response.Fight or flight response means when our body is at critical situation or serious illness, this system activates to save us.It is totally physiological and involuntary.It increases heart rate,breath rate and try to save us.This way it is very much helpful to us.

2. Parasympathetic nervous system

It is also involuntary but it works for rest and digestion.It means when we are at rest this system helps to maintain body functions.

When we are sleeping it decreases heart rate and do changes what body needs at rest.It helps in digestion by increasing activity of intestine,increasing gastric secretion and relaxing pyloric sphincter.It is called rest and digestion response of PNS.

This way in this blog we just learn basic information. It is like suspense movie, so just one point if we miss the further topics will be not clear.So go through other topics one by one.In next blog we learn about Neuron.

If you want to watch video on above text than watch video giving below link.