Hey Dori, I need your help learning parts of the Nervous System of the human body! I will do my best to keep up and help you along the way!

I would love to! You know they say I am the brain of the sea....Anyways lets go don't trail behind me and keep up!

Nemo and Dori venture out into the sea, they see many colorful and different kinds of sea animals. Nemo could barely hold his excitement

WEEE..This is so fun. I love exploring..

Keep quiet kid!

On the way Nemo and Dori pass by a school of fish heading for school.

DOES ANYONE KNOW IF CNS WILL BE ON THE TEST!!!!

Dori what is CNS?

Yes it will be make sure you know it...

The school of fish were on their way to take their anatomy exams. They have been preparing for a while...

Central Nervous System has your brain and spinal cord. Brain is the command center for your body and the spinal cord is a pathway used to get messages/signals across.

WOW... that is so cool Dori.

Do I have a brain?

Umm.. sometimes it's questionable if you do or not...

What is that supposed to mean?

Oh nothing... you know there is also the Peripheral Nervous System, which is all the nerves in your body.

Nemo and Dori continue their journey and find something in the middle of the colorful corals..... 

Dori Dori, I found something... it doesn't look colorful what is that?

Good eye! Looking at this close up, this is the spinal meninges, this is specialized

membranes that separate and protects spinal cord from surroundings and it carries blood supply...

Since we are talking about spinal cord, let me tell you all about it..so sit back...

The spinal cord is the pathway for messages sent from the body to brain and vice versa. The human spinal cord is much longer than ours Nemo, their's is about 45 cm long and it can be divided into 31 segments. There is also this thing known as Gray and White Matter of Spinal Cord. The Gray Matter has unmyelinated neurons (which makes it slower at sending signals) and it is responsible for the processing of Spinal reflexes. Next, White Matter is made of myelinated neurons (fastest way to send signals). It has two functions,  Ascending tracts carry sensory information to the brain and Descending tracts carry motor commands to the effector

WOW! That was a lot of information, hopefully I remember it all..

HAHAHA, I didn't tell you the Human Nervous system was easy.....

As they travel down the sea, Dori continues her lesson on the spinal cord, but Nemo seems to be very distracted..

OOOO pearls!!!!

Continuing with the spinal-NEMO!!! PAY ATTENTION... I knew you would loose tract.

I am sorry, these pearls are just so pretty. I could bring them back for dad..

Do not interfere with ocean life you should know better Nemo.. Leave the pearls where there are. Shall I continue with the lesson?

Yes, I'm sorry..

Anyways...Next spinal nerves: nerves are a bundle of axons, blood vessels and connective tissue that binds everything together. Each spinal nerve is mixed, which means they carry both sensory and motor information and are numbered in the same manner as the vertebrae. The nerve plexus is a complex, interwoven web, basically a plexus of intersecting nerves, they allow some overlap and backup pathways for nerve impulses. There are many types of plexuses; cervical plexus provides nerve connections to the head, neck, and shoulder. The brachial plexus provides connections to the chest, shoulders, arms. The lumbar and sacral plexuses provides connection lower back, pelvis and legs..., Are you getting this Nemo?

Yes, the human body is so complicated. I am happy as a fish. Are you happy Dori?

Yes, Nemo I love my life as a fish.. Now would you like to learn about the different kinds of nerves and their functions??

A light bulb goes on in Nemo's mind...

Wait... I remember watching the Discovery Channel of Humans with my dad. I can tell you all about it Dori. Can I please???

Sure, let's see what you know.

Okay so.. there are many kinds of spinal nerves in the human body each with their own function. Some of the nerves are Ulnar, Radial, Femoral, Phrenic and many more. The phrenic nerve is responsible for controlling the diaphragm. Median nerves supplies the flexors of forearm and radial half of palm; control coarse movements of the hand. The femoral nerve supplies muscles of thigh and anterior skin. The ulnar nerve supplies the flexor muscles of the forearm and the hand. Lastly, the radial nerve supplies the muscles of the leg.

Wow Nemo.. I am impressed that you know all this but you got one piece of information wrong.. The-

WHATTTT????

Angry Nemo swims off

Nemo come backkk.... why are you so angry, it is okay to be wrong

Leave me alone.. I am ashamed of myself.

It is okay to be wrong, nothing to be ashamed of. Even I am wrong sometimes. As long as you are learning..

You know what you are right Dori.. what was I wrong about

Oh you said the radial nerve supplies the muscles of the leg, but it supplies the muscles located in the posterior arms down through the hand.

To end the Spinal lesson, let's talk about Spinal reflexes. They are simple behaviors produced by the central nervous system. The sensory fibers that evoke this reflexes enter the spinal cord and activate spinal motor neurons: basically than there is a rapid, automatic nerve responses triggered by specific stimuli and the Gray Matter processes these spinal reflexes.

Thank you Dori, I already know so much about the nervous system now.

So, what is next Dori?

let's move on to the brain.

Here Nemo this is an overview of the human brain..

Now let's talk about these parts...The cerebrum is the largest part of the brain and it controls all conscious thoughts and intellectual functions of a human (speech, voluntary movement) and processes somatic sensory and motor information. It is divided into two halves called cerebral hemisphere. The cerebellum is the “small brain” below occipital lobe Just like the cerebrum, the cerebellum is also divided into two halves called hemispheres. Then the brain stem, processes information between spinal cord and cerebrum or cerebellum. We will go into more details about these later. The CSF (as you saw the in the picture) it the blue outline outside of the brain and it is known as Cerebrospinal fluid which is a clear, colorless body fluid that surrounds the brain and spinal cord.

Can you tell me more about the cerebrum?

Sure.. as I said before the cerebrum has two hemispheres and the surface of each hemisphere is composed of a layer of gray matter called the cerebral cortex, each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body known as contra lateral. The two hemispheres have different functions, although their structures are alike. In humans, it said to be, if their left hemisphere is the dominant one then they are more logical and if the right one is more dominant then they are more creative.

Here on the right side a picture of the lobes located in the brain. We have the frontal, parietal, occipital and temporal lobe. Each frontal lobe is responsible for functional areas of the Cerebral Cortex (where there are located). The primary motor cortex – controls all voluntary movements (skeletal muscles) and the premotor cortex - coordinates motor responses (learned movements/muscle memory), the motor writing center - coordinates the fine movements of the hands (like writing) and these are found in the frontal lobe. The primary sensory cortex: receives somatic sensory information (touch, pain) and the somatic sensory association area - interprets and processes input to primary sensory cortex, these are in the parietal lobe. In the temporal lobe they have the auditory cortex- information from sound receptors and the auditory association area - interprets that information. In the occipital lobe- the visual cortex -information from sight receptors ( like shape) and the visual association area-interprets activity in visual cortex.