This Book is dedicated to Mr. Wilson, the one and only teacher that actually helps his students understand the material, and makes sure everyone has an equal opportunity to succeed.
Welcome to the magic land of Smarts
My name is Brad the brain, and I'll take you on a magical ride throughout the Nervous System!
There's two major parts to the nervous system...
There's the Central Nervous System, which controls most body functions and the mind!
This includes only the brain and spinal cord.
It controls all voluntary movement, such as speech and walking, and involuntary movements such as blinking and breathing.
It also is where all conscious thought occurs!
Then there's the peripheral nervous system, which includes all other nerves outside of the brain and brainstem
Meninges: layer of protective tissue, composed of 3 main layers: The dura mater, the arachnoid layer, and the Pia mater. Main functions of meninges: protecting the brain and spinal cord from mechanical injury. Dura mater: outermost layer of the meninges, has its own blood supply, its pain sensitive.
The arachnoid layer: the layer right under the dura mater
The pia mater: innermost layer lining the brain. It has blood vessels that deliver oxygen and nutrients to spinal cord.
Dura mater: outermost layer of the meninges, has its own blood supply, its pain sensitive.
The arachnoid layer: the layer right under the dura mater
Here we see the spinal cord! It is a long rope, that extends from the brain to the lower back. It contains white and gray matter, and every single nerve in the body attaches to this cord.
The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. If any part of this is damaged, then the consequences could be minor loss of feeling or sense, or completely paralyzed to the point of needing life support. If damage occurs, anything below the point of damage on the spinal cord will result in paralysis.
The GRAY MATTER in the spinal cord allows for processing, while taking up little space. The impulse would travel at around 1 mile per hour. An example of a use would be reflexes.
The WHITE MATTER in the spinal cord is used for very fast transferring of signals. It is wrapped with MYELIN, which allows for the signal to travel up to 280 miles per hour.
Gray matter
White matter
The white matter is used for long distance signal travel, while the gray matter is used for very short distance travel, and for processing in the brain.
White Matter is used in the ascending tracts and descending tracts for fast signal transferring, while Gray Matter would be used in the brain stem to help the DIENCEPHALON, MIDBRAIN, PONS, and MEDULLA OBLONGATA to make decisions.
Spinal nerves have two different roots, which are dorsal and ventral roots. Dorsal roots and dorsal root ganglion are sensory nerves, which detect the impulse.
Ventral roots are the nerves that send out the signal as motor commands.
A spinal nerve is actually just a bundle of axons. Every nerve is mixed, which means that they carry both sensory and motor commands. This is because each nerve goes to its own individual body part, and controls/senses that entire area.
All Spinal nerves are mixed which means they can carry both sensory and motor information.
Axillary nerve: supplies three muscles in the arm, which are deltoid(a muscle of the shoulder), teres minor (one of the rotator cuffmuscles) and the long head of the triceps brachii.
Thoracic nerve: Muscles and skin of thoracic wall, which is sent up to the brain with signals from the abdomen.
Nerves
Median wall: flexors of forearm and radial half of palm
Ulnar nerve: Ulnar side of forearm and hand.
Every nerve has its own function! There are some nerves that only send the signal from the receptor, and some nerves only send the signal from the CNS. However most nerves will send a mix of both signals from receptors, and signals from the CNS to the same exact spot! WOW!!
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The cerebellum is also divided into two halves called hemispheres and covered in an outer layer of gray matter called cerebella cortex. The cerebellum receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements. The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity. It is also important for learning motor behaviors.
Theres four major plexuses in the human body. They are the cervical, brachial, lumbar and sacral plexuses. Plexuses are areas where nerves bunch up together inorder to send impulses to the brain!
The Cervical Plexus is located in the neck of the human body, and serves as an area for hearing, facial nerves, and other nerves in the area to combine and send impulses.
Then there's the brachial plexus, which gathers nerves from the arms and hands!
After that, the last plexuses are the lumbar and sacral plexuses. The lumbar plexus will gather nerves from the back. The sacral plexus will gather nerves from the legs, theighs, and buttocks.
How spinal reflex works: These are rapid, automatic nerve responses that are triggered by specific stimuli. They are controlled by the spinal cord gray matter, and not by the brain. This is because they need to be even faster. This gray matter is what controls our reflexes. When we see something move fast or come at us fast, our eyes follow it to makes sure its not going to harm us.
Cerebrospinal Fluid (CSF): Clear, colorless body fluid found in the brain and spine.
Function: It helps protects from physical injury and help control the chemical environment of brain, supplies nutrients to nervous system tissue and removes waste products from cerebral metabolism.
Cerebrum: largest part of the brain. It controls all conscious thoughts and intellectual functions, processes somatic sensory and motor information. The surface of the each hemispheres is composed of a layer of gray matter called the cerebral cortex. One hemisphere, usually the left, is functionally dominant, controlling language and speech. The other hemisphere interprets visual and spatial information.
The CEREBELLUM is located in the back of the brain, and it fine tunes all movements. The movements will start out from the cerebrum, and before they make their way to the muscles, the cerebellum will fix any errors so that everything goes smoothly.
The brain stem is the 'funnel' to the brain, and it is more than just a bunch of nerves.
Theres also major structures of the brain that we should look at. One of the biggest structures are the Corpus Callosum, which connects both sides of the brain together so they can share motor and sensory information. It could be referred to as "The Bridge".
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This Book is dedicated to Mr. Wilson, the one and only teacher that actually helps his students understand the material, and makes sure everyone has an equal opportunity to succeed.
Welcome to the magic land of Smarts
My name is Brad the brain, and I'll take you on a magical ride throughout the Nervous System!
There's two major parts to the nervous system...
There's the Central Nervous System, which controls most body functions and the mind!
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