Methods of Learning (Operating System - II)

Which Type of Learner Are You ?

Left Sided Learner (Analytic Method):

1. Successive Hemispheric Style
2. Verbal
3. Responds to word meaning
4. Sequential
5. Processes information linearly
6. Responds to logic
7. Plans ahead
8. Recalls people's names
9. Speaks with few gestures
10. Punctual
11. Prefers formal study design
12. Prefers bright lights while studying

Right Sided Learner (Global Method):

1. Simultaneous Hemispheric Style
2. Visual
3. Responds to tone of voice
4. Random
5. Processes information in varied order
6. Responds to emotion
7. Impulsive
8. Recalls people's faces
9. Gestures when speaking
10. Less punctual
11. Prefers sound/music background while studying
12. Prefers frequent mobility while studying

Methods of Learning:

In general the left and right hemispheres of your brain process information in different ways. We tend to process information using our dominant side. However, the learning process is enhanced when all of our senses are used. Read the information below to help you understand how your brain processes information. Pay attention to your less dominant style so that you can learn how to improve it.

Linear vs. Holistic Processing

The left side of the brain processes information in a linear manner. It process from part to whole. It takes pieces, lines them up, and arranges them in a logical order; then it draws conclusions. The right brain, however, processes from whole to part, holistically. It starts with the answer. It sees the big picture first, not the details. If you are right-brained, you may have difficulty following a lecture unless you are given the big picture first. Do you now see why it is absolutely necessary for a right-brained person to read an assigned chapter or background information before a lecture or to survey a chapter before reading? If an instructor doesn't consistently give an overview before he or she begins a lecture, you may need to ask at the end of class what the next lecture will be and how you can prepare for it. If you are predominantly right-brained, you may also have trouble outlining (you've probably written many papers first and outlined them latter because an outline was required). You're the student who needs to know why you are doing something. Left-brained students would do well to exercise their right-brain in such a manner.

Sequential vs. Random Processing

In addition to thinking in a linear manner, the left brain processes in sequence -- in order. The left-brained person is a list maker. If you are left-brained, you would enjoy making a master schedule and doing daily planning. You complete tasks in order and take pleasure in checking them off when they are accomplished. Likewise, learning things in sequence is relatively easy for you. For example, spelling involves sequencing; if you are left-brained, you are probably a good speller. The left brain is also at work in the linear and sequential processing of math and in following directions.

By contrast, the approach of the right-brained student is random. If you are right-brained, you may flit from one task to another. You will get just as much done but perhaps without having addressed priorities. An assignment may be late or incomplete, not because you weren't working, but because you were working on something else. You were ready to rebel when asked to make study schedules for the week.  But because of the random nature of your dominant side, you must make lists, and you must make schedules. This may be your only hope for survival in college. You should also make a special effort to read directions. The mention of spelling makes you cringe. Use the dictionary, carry or use the spell checker on your computer. Never turn in an assignment without proofing for spelling. Because the right side of the brain is color sensitive, you might try using colors to learn sequence, making the first step green, the second blue, the last red. Or you may want to "walk" a sequence, either by physically going from place to place or by imagining it. For the first step of the sequence, you might walk to the front door; for the second, to the kitchen; for the third, to the den, etc. Or make Step One a certain place or thing in your dorm room or study place and Step Two another. If you consistently use the same sequence, you will find that this strategy is transferable to many tasks involving sequence.

Symbolic vs. Concrete Processing

The left brain has no trouble processing symbols. Many academic pursuits deal with symbols such as letters, words, and mathematical notations. The left-brained person tends to be comfortable with linguistic and mathematical endeavors. Left-brained students will probably just memorize vocabulary words or math formulas. The right brain, on the other hand, wants things to be concrete. The right-brained person wants to see, feel, or touch the real object. Right-brained students may have had trouble learning to read using phonics. They prefer to see words in context and to see how the formula works. To use your right brain, create opportunities for hands-on activities. Use something real whenever possible. You may also want to draw out a math problem or illustrate your notes.

Logical vs. Intuitive Processing

The left brain processes in a linear, sequential, logical manner. When you process on the left side, you use information piece by piece to solve a math problem or work out a science experiment. When you read and listen, you look for the pieces so that you can draw logical conclusions. Your decisions are made on logic--proof. If you process primarily on the right side of the brain, you use intuition. You may know the right answer to a math problem but not be sure how you got it. You may have to start with the answer and work backwards. On a quiz, you have a gut feeling as to which answers are correct, and you are usually right. In writing, it is the left brain that pays attention to mechanics such as spelling, agreement, and punctuation. But the right side pays attention to coherence and meaning; that is, your right brain tells you it "feels" right. Your decisions will be based on feelings.

Verbal vs. Non-verbal Processing :

Left-brained students have little trouble expressing themselves in words. Right-brained students may know what they mean but often have trouble finding the right words. The best illustration of this is to listen to people give directions. The left-brained person will say something like "From here, take first left, then proceed further, take second right. Move 2 kilometer further take left." The right-brained person will sound something like this: "Turn lest (pointing left) by the church over there (pointing again). Then take right turn at the Star Mall. Then take left turn at Kohinoor Bakery.” So how is this relevant to planning study strategies? Right-brained students need to back up everything visually. If it's not written down, they probably won't remember it. And it would be even better for right-brained students to illustrate it. They need to get into the habit of making a mental video of things as they hear or read them. Right-brained students need to know that it may take them longer to write a paper, and the paper may need more revision before it says what they want it to say. This means allowing extra time when a writing assignment is due

Reality-Based vs. Fantasy-Oriented Processing

The left side of the brain deals with things the way they are--with reality. When left-brained students are affected by the environment, they usually adjust to it. Not so with right-brained students; they try to change the environment! Left-brained people want to know the rules and follow them. In fact, if there are no rules for situations, they will probably make up rules to follow. Left-brained students know the consequences of not turning in papers on time or of failing a test, but right-brained students are sometimes not aware that there is anything wrong. So, if you are right-brained, make sure you constantly ask for feedback and reality checks. It's too late the day before finals to ask if you can do extra marks. Keep a careful record of your assignments and tests. Visit with your \teacher routinely. While this fantasy orientation may seem a disadvantage, in some cases it is an advantage. The right-brained student is creative. In order to learn about the digestive system, you may decide to become a piece of food! And since emotion is processed on the right side of the brain, you will probably remember well anything you become emotionally involved in as you are trying to learn.

These are just some of the differences that exist between the left and right hemispheres, but you can see a pattern. Because left-brained strategies are the ones used most often in the classroom, right-brained students sometimes feel inadequate. However, you now know that you can be flexible and adapt material to the right side of your brain. Likewise, those of you who are predominantly left-brained know that it would be wise to use both sides of the brain and employ some right-brained strategies.

Understanding Operating System of Brain

Test to find which side of the brain you use the most?

Directions:

Get a blank sheet of lined paper. Every time you read a description or characteristic that applies to you, write down its number on the blank sheet of paper. There is no certain number of characteristics you must choose. After you are done, go to the end of this blog. Next to every number on your paper, write whether it was a L or an R. Count up the number of L's and R's. Whichever number is higher represents your dominance. If the numbers are close, that means you use both sides of your brain equally.

1. I constantly look at a clock or wear a watch
2. I keep a journal or diary of my thoughts
3. I believe there is a either right and wrong way to do everything
4. I find it hard to follow directions precisely
5. The expression "Life is just a bowl of cherries" makes no sense to me
6. I frequently change my plans and find that sticking to a schedule is boring
7. I think it's easier to draw a map than tell someone how to get somewhere
8. To find a lost item, I try to picture it in my head where I last saw it
9. I frequently let my emotions guide me
10. I learn math with ease
11. I'd read the directions before assembling something
12. People tell me I am always late getting places
13. People have told me that I'm psychic
14. I need to set goals for myself to keep me on track
15. When somebody asks me a question, I turn my head to the left
16. If I have a tough decision to make, I write down the pros and the cons
17. I'd probably make a good detective
18. I learn music with ease
19. To solve a problem, I think of similar problems I have solved in the past
20. I use a lot of gestures
21. If someone asks me a question, I turn my head to the right
22. I believe there are two ways to look at almost everything
23. I have the ability to tell if people are lying or guilty of something, just by looking at them
24. I keep a "to do" list
25. I am able to thoroughly explain my opinions in words
26. In a debate, I am objective and look at he facts before forming an opinion
27. I've considered becoming a poet, a politician, an architect, or a dancer
28. I always lose track of time
29. When trying to remember a name I forgot, I'd recite the alphabet until I remembered it
30. I like to draw
31. When I'm confused, I usually go with my gut instinct
32. I have considered becoming a lawyer, journalist, or doctor

1. L
2. L
3. L
4. R
5. L
6. R
7. R
8. L
9. R
10. L
11. L
12. R
13. R
14. L
15. R
16. L
17. L
18. R
19. R
20. R
21. L
22. R
23. R
24. L
25. L
26. L
27. R
28. R
29. L
30. R
31. R
32. L

An important factor in understanding learning styles is understanding brain functioning. Both sides of the brain can reason, but by different strategies. and one side may be dominant. The left brain is considered analytic in approach while the right is described as holistic or global. A successive processor (left brain) prefers to learn in a step-by-step sequential format, beginning with details leading to a conceptual understanding of a skill. A simultaneous processor ( right brain) prefers to learn beginning with the general concept and then going on to specifics.

Know The Hardware (Nervous System - VII)

Differences in the brains of males and females:

 

Total brain size:

In adults, the average brain weight in men is about 11-12% MORE than the average brain weight in women. Men's heads are also about 2% bigger than women's. . This is due to the larger physical stature of men. Male’s larger muscle mass, and larger body size require more neurons to control them. This does not suggest that due to the larger brain, males are smarter than females.

 

Cell number:

men have 4% more  brain cells than women , and about 100 grams more of brain tissue. this may explain why women are more prone to dementia (such as Alzheimer's disease) than  men, because although both may lose the same number of neurons due to the disease, "in males, the functional reserve may be greater as a larger number of nerve cells are present, which could prevent some of the functional losses."

 

Cellular connections:

while men have more neurons in the cerebral cortex, women have a more developed neuropil, or the space between cell bodies, which contains synapses, dendrites and axons, and allows for communication among neurons .

 

Corpus callosum:

it is reported that a woman's brain has a larger corpus collusum, which means women can transfer data between the right and left hemisphere faster than men. Men tend to be more left brained, while women have greater access to both sides

 

Language:

two areas in the frontal and temporal lobes related to language (the areas of Broca and Wernicke) were significantly larger in women, thus providing a biological reason for women's notorious superiority in language-associated thoughts. For men, language is most often just in the dominant hemisphere (usually the left side), but a larger number of women seem to be able to use both sides for language. This gives them a distinct advantage. If a woman has a stroke in the left front side of the brain, she may still retain some language from the right front side. Men who have the same left sided damage are less likely to recover as fully. Curiously, oriental people which use pictographic (or ideographic) written languages tend also to use both sides of the brain, regardless of gender.

 

Inferior parietal lobule (IPL):

it is a brain region in the cortex, which is significantly larger in men than in women. This area is bilateral and is located just above the level of the ears (parietal cortex). Furthermore, the left side IPL is larger in men than the right side. In women, this asymmetry is reversed, although the difference between left and right sides is not so large as in men. This is the same area which was shown to be larger in the brain of Albert Einstein, as well as in other physicists and mathematicians. So, it seems that IPL's size correlates highly with mental mathematical abilities. Studies have linked the right IPL with the memory involved in understanding and manipulating spatial relationships and the ability to sense relationships between body parts. It is also related to the perception of our own affects or feelings. The left IPL is involved with perception of time and speed, and the ability of mentally rotate 3-D figures .

 

Orbitofrontal to amygdale ratio (OAR):

In one project, they measured the size of the orbitofrontal cortex, a region involved in regulating emotions, and compared it with the size of the amygdala, implicated more in producing emotional reactions. The investigators found that women possess a significantly larger orbitofrontal-to-amygdala ratio (OAR) than men do. One can speculate from these findings that women might on average prove more capable of controlling their emotional reactions.

 

Limbic size:

females, on average, have a larger deep limbic system than males. This gives females several advantages and disadvantages. Due to the larger deep limbic brain women are more in touch with their feelings, they are generally better able to express their feelings than men. They have an increased ability to bond and be connected to others. Females have a more acute sense of smell, which is likely to have developed from an evolutionary need for the mother to recognize her young. Having a larger deep limbic system leaves a female somewhat more susceptible to depression, especially at times of significant hormonal changes such as the onset of puberty, before menses, after the birth of a child and at menopause. Women attempt suicide three times more than men. Yet, men kill themselves three times more than women, in part, because they use more violent means of killing themselves (women tend to use overdoses with pills while men tend to either shoot or hang themselves) and men are generally less connected to others than are women.

Know The Hardware - VI (Nervous System)

Bicameral Mind (Left Brain and Right Brain)

The term Bicameral Mind (Two Parts) was coined by psychologist Julian Jaynes, who presented the idea in his 1976 book "The Origin of Consciousness in the Breakdown of the Bicameral Mind". It says that each of us is really two people. It means we are literally two thinking beings residing in the same body.

Consider an interesting exercise in which a college psychology professor had taken photographs of her students, made copies that were flipped left to right, and then had them cut in half vertically. She reassembled the images using the two similar sides of the face.

See following photographs of president Nixon, made by above method.

       left+left                 Normal            right+right

[A quick way to do this is to place a small mirror perpendicular to a photograph showing a good front face view. As you look into the mirror you can form a whole face from the reflection of either side.]

She found that the composite pictures were humorous. Although the individuals were easily recognizable, their facial expressions seemed to express exaggerated emotions, like anger, suspicion, or happiness. interesting observation was that the two sides of the same face were often so different.

This exercise seemed to suggest that, while very few people have symmetrical faces, a vast majority of us do not. Also it raised the possibility that each side of our face could express different emotions at the same time! Subsequent research into facial expressions and the workings of the human brain has offered an interesting theory that not only explains this left and right difference in facial expressions, but could help us to understand our "other self."

Our brain, like the rest of our anatomy, is made up of two halves, a left brain a right brain. They are connected to each other by a thick cable of nerves at the base of each brain. This sole link between the two giant processors is called the corpus collosum. Think of it as an Ethernet cable or network connection between two incredibly fast and immensely powerful computer processors, each running different programs from the same input.

The left side of our body is "wired" to the right side of our brain, and vice versa. For whatever reason nature did this cross-over, it applies even to our eyes, which process a majority of their sensory data on opposite sides of the brain.

Roger Sperry's Experiments:

We should thank Nobel Prize Winner (1981) Roger Sperry for this next contribution. Sperry conducted what are sometimes called the "split-brain" experiments. Here's how it went: A patient suffering from uncontrolled seizures (epilepsy) had an area of his brain removed by surgery in an attempt to control his illness. This area just happened to be the corpus collosum, which was suspected of having developed lesions (short circuits).

Following his surgery, Sperry's patient seemed completely normal -- almost. A series of tests were conducted where each "half" of the patient was isolated from the other. Different visual and tactile information could then be presented to the patient's left or right side, without the other side knowing. The results were astounding.

With their communications link severed, each side of the patient's brain was functioning independently. Although this did not prevent his ability to walk, talk and eat, some unexpected findings were encountered in some of the higher brain functions when each side was examined independently of the other.

The right hand and eye could name an object, such as a pencil, but the patient could not explain what it was used for. When shown to the left hand and eye, the patient could explain and demonstrate its use, but could not name it. Further studies showed that various functions of thought are physically separated and localized to a specific area on either the left or right side of the human brain. This functional map is consistent for an estimated 70 to 95 percent of us.

The main theme to emerge... is that there appear to be two modes of thinking, verbal and nonverbal, represented rather separately in left and right hemispheres respectively and that our education system, as well as science in general, tends to neglect the nonverbal form of intellect. What it comes down to is that modern society discriminates against the right hemisphere.    -Roger Sperry (1973)

Functions of the Two Brains:

Upon completing the map, it was becoming clear to researchers that each side of the brain had a characteristic way that it both interpreted the world and reacted to it. The chart below will help illustrate the characteristics which are known to reside on each side of our brains.

LEFT BRAIN FUNCTIONS uses logic detail oriented facts rule words and language present and past math and science can comprehend knowing acknowledges order/pattern perception knows object name reality based forms strategies practical safe

RIGHT BRAIN FUNCTIONS uses feeling "big picture" oriented imagination rules symbols and images present and future philosophy & religion can "get it" (i.e. meaning) believes appreciates spatial perception knows object function fantasy based presents possibilities impetuous risk taking

Our personality can be thought of as a result of the degree to which these left and right brains interact, or, in some cases, do not interact. It is a simplification to identify "left brain" types who are very analytical and orderly. We likewise certainly know of the artistic, unpredictability and creativity of "right brain" types. But each of us draws upon specific sides of our brain for a variety of daily functions, depending on such things as our age, education and life experiences. The choices of which brain is in control of which situations is what forges our personalities and determines our character.

Important Findings:

Experiments show that most children rank highly creative (right brain) before entering school. Because our educational systems place a higher value on left brain skills such as mathematics, logic and language than it does on drawing or using our imagination, only ten percent of these same children will rank highly creative by age 7. By the time we are adults, high creativity remains in only 2 percent of the population.

The War of the Twins,  the Left Brain and Right Brain:

The two brains not only see the world in vastly different ways but, in our current society, the left side just "doesn't get" what the right side is all about. It tends to dismiss anything significant coming into consciousness from its cranial twin. Sometimes two sides can actually disagree, resulting in our perception of emotional turmoil from the expressive protests of right brain.

Our conscious mind can only focus on data from one brain at a time. We can switch from one side to the other very quickly (with our corpus collosum intact) but that's not always the most efficient way to act and eventually ultimate authority to enter consciousness is delegated to one brain or the other. In our modern world, this battle is almost always won by the left brain.

It appears that most people will never reach their maximum potential because of compromises that have been made between these two governing bodies. Sometimes skills which the right brain can perform better are routinely handled, with less skill, by the left brain. Ideally, both brains work together in people with optimum mental ability. This coordinating ability may be the key to superior intellectual abilities. In most people, however, the left brain takes control, choosing logic, reasoning and details over imagination, holistic thinking and artistic talent.

Methods have been devised to "shut off" the left brain, allowing the right side to have its say. Creative writing courses often use this method to combat "writer's block." The logical left side is easily bored by lack of input and tends to "doze off" during such activities as meditation (repeating a mantra or word over and over or meditation) or in sensory deprivation environments. The right brain is then able to "sneak" into our consciousness, filling our minds with emotional and visual capacity and freely associated images. But the left brain will assert itself and dispense with these irrational images, asserting its Spock-like logical dominance and the right brain will have to be content to find expression in dreams.

Know The Hardware - V (Nervous System)

Neurotransmitters and Neuroactive Peptides

Communication of information between neurons is accomplished by movement of chemicals across a small gap called the synapse. Chemicals, called neurotransmitters, are released from one neuron at the presynaptic nerve terminal. Neurotransmitters then cross the synapse where they may be accepted by the next neuron at a specialized site called a receptor.

Neurotransmitter Criteria

Neuroscientists have set up a few guidelines or criteria to prove that a chemical is really a neurotransmitter. 

1.  The chemical must be produced within a neuron.
2.  The chemical must be found within a neuron.
3. When a neuron is stimulated (depolarized), a neuron must release the chemical
4. When a chemical is released, it must act on a post-synaptic receptor and cause a biological effect.
5. After a chemical is released, it must be inactivated. Inactivation can be through a reuptake mechanism or by an enzyme that stops the action of the chemical
6. If the chemical is applied on the post-synaptic membrane, it should have the same effect as when it is released by a neuron

Neurotransmitter Types

There are many types of chemicals that act as neurotransmitter substances. Below is a list of some of them.

Small Molecule Neurotransmitter Substances

Acetylcholine (ACh), Dopamine (DA), Norepinephrine (NE), Serotonin (5-HT), Histamine, Epinephrine

Amino Acids

Gamma-aminobutyric acid (GABA), Glycine, Glutamate, Aspartate

Neuroactive Peptides

bradykinin	beta-endorphin	bombesin	calcitonin
cholecystokinin	enkephalin	dynorphin	insulin
gastrin	substance P	neurotensin	glucagon
secretin	somatostatin	motilin	vasopressin
oxytocin	prolactin	thyrotropin	angiotensin II
sleep peptides	galanin	neuropeptide Y	thyrotropin-releasing hormone
gonadotropnin-releasing hormone	growth hormone-releasing hormone	luteinizing hormone	vasoactive intestinal peptide

Soluble Gases

Nitric Oxide (NO), Carbon Monoxide

Functions of Neurotransmitters:

Acetylcholine (ACh)

Distributed widely throughout the central and peripheral nervous system, where it is involved in arousal, attention, memory, motivation, and movement. Involved in muscle action through presence at neuromuscular junctions (specialized type of synapse where neurons connect to muscle cells). Degeneration of neurons that produce ACh have been linked to Alzheimer’s disease. Too much can lead to spasms and tremors; too little, to paralysis.

Dopamine

Involved in a wide variety of behaviors and emotions, including pleasure. Implicated in schizophrenia and Parkinson’s disease.

Serotonin

Involved in the regulation of sleep, dreaming, mood, eating, pain, and aggressive

behavior. Implicated in depression.

Norepinephrine

Affects arousal, wakefulness, learning, memory, and mood.

Endorphins

Involved in the inhibition of pain. Released during strenuous exercise. May be

responsible for “runner’s high.” Glutamate Involved in long-term memory and the perception of pain.

GABA

A largely inhibitory neurotransmitter distributed widely throughout the central (Gamma aminobutyric acid) nervous system. Implicated in sleep and eating disorders. Low levels of GABA have also been linked to extreme anxiety.

Glycene

Principally responsible for inhibition in the spinal cord and lower brain centers.

Know The Hardware - IV (Nervous System)

Brain Structure

Cerebral Cortex (Intellectual Brain)

Functions: Voluntary movement, Language, Reasoning, Perception, Processing of visual data, Auditory data, Talking, Hearing, Thinking and Problem solving.

The word "cortex" comes from the Latin word for "bark" (of a tree). This is because the cortex is a sheet of tissue that makes up the outer layer of the brain. The thickness of the cerebral cortex varies from 2 to 6 mm. The right and left sides of the cerebral cortex are connected by a thick band of nerve fibers called the "corpus callosum." In higher mammals such as humans, the cerebral cortex looks like it has many bumps and grooves. A bump or bulge on the cortex is called a gyrus (the plural of the word gyrus is "gyri") and a groove is called a sulcus (the plural of the word sulcus is "sulci"). Lower mammals, such as rats and mice, have very few gyri and sulci.

Limbic System (Mammalian Brain / Emotional Brain)

Functions: Emotions, Memory

The limbic system (or the limbic areas) is a group of structures that includes the amygdala, the hippocampus, mammillary bodies and cingulate gyrus. These areas are important for controlling the emotional response to a given situation. The hippocampus is also important for memory.

Thalamus

Functions:  Sensory processing, Movement

The thalamus receives sensory information and relays this information to the cerebral cortex. The cerebral cortex also sends information to the thalamus which then transmits this information to other areas of the brain and spinal cord.

Midbrain

Functions:  Vision, Audition, Eye Movement, Body Movement

The midbrain includes structures such as the superior and inferior colliculi and red nucleus. There are several other areas also in the midbrain.

Hypothalamus

Functions:  Body Temperature, Emotions, Hunger, Thirst, Circadian Rhythms

The hypothalamus is composed of several different areas and is located at the base of the brain. Although it is the size of only a pea (about 1/300 of the total brain weight), the hypothalamus is responsible for some very important functions. One important function of the hypothalamus is the control of body temperature. The hypothalamus acts as a "thermostat" by sensing changes in body temperature and then sending signals to adjust the temperature. For example, if you are too hot, the hypothalamus detects this and then sends a signal to expand the capillaries in your skin. This causes blood to be cooled faster. The hypothalamus also controls the pituitary.

Hippocampus

Functions:  Learning, Memory

The hippocampus is one part of the limbic system that is important for memory and learning.

Reptilian Brain (Instinctive Brain)

Cerebellum

Functions: Movement, Balance, Posture

The word "cerebellum" comes from the Latin word for "little brain." The cerebellum is located behind the brain stem. In some ways, the cerebellum is similar to the cerebral cortex: the cerebellum is divided into hemispheres and has a cortex that surrounds these hemispheres.

Brain stem

Functions: Breathing, Heart Rate, Blood Pressure, Sense of territory, Flight or fight sense

The brain stem is a general term for the area of the brain between the thalamus and spinal cord. Structures within the brain stem include the medulla, pons, tectum, reticular formation and tegmentum.

Note: (Very Important)

When placed under negative stress your brain enters its reptilian state. It meets your basic instincts.  It is then extremely difficult to learn.  The ideal state for learning is one of low stress and high challenge. If you want to learn or study do it without stress.

 

Know The Hardware - III (Nervous System)

The nervous system is divided into the central nervous system and peripheral nervous system.

Central Nervous System: (C.N.S.)

The central nervous system is divided into two parts: the brain and the spinal cord. The brain contains about 100 billion nerve cells (neurons) and trillons of "support cells" called glia. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about 35-40 grams. The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long. Therefore, the spinal cord is much shorter than the vertebral column. Structure and different regions of brain are to be discussed in coming blogs.

Peripheral Nervous System (P.N.S.)

The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system.

Somatic Nervous System

 

The somatic nervous system consists of peripheral nerve fibers that send sensory information to the central nervous system AND motor nerve fibers that project to skeletal muscle. The figure shows the somatic motor system. The cell body is located in either the brain or spinal cord and projects directly to a skeletal muscle.

Autonomic Nervous System 

The autonomic nervous system is divided into three parts: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system. The autonomic nervous system controls smooth muscle of the viscera (internal organs) and glands.

The figure shows the general organization of the autonomic nervous system. The preganglionic neuron is located in either the brain or the spinal cord. This preganglionic neuron projects to an autonomic ganglion. The postganglionic neuron then projects to the target organ. Notice that the somatic nervous system has only one neuron between the central nervous system and the target organ while the autonomic nervous system uses two neurons.

In the peripheral nervous system, neurons can be functionally divided in three ways:

1. Sensory (afferent) - carry information INTO the central nervous system from sense organs or motor (efferent) - carry information away from the central nervous system (for muscle control).
2. Cranial - connects the brain with the periphery or spinal - connects the spinal cord with the periphery.
3. Somatic - connects the skin or muscle with the central nervous system or visceral - connects the internal organs with the central nervous system.

Note:

1. In the CNS, collections of neurons are called nuclei. In the PNS, collections of neurons are called ganglia.
2. In the CNS, collections of axons are called tracts. In the PNS, collections of axons are called nerves.