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The Dr. started the lecture by saying: that he gave us everything we have to know about the

Central Nervous System (CNS) and it will take us month talking about the Physiology of it,,, blah

blah blah !!!

The last lecture we talked about the Central & peripheral Nervous System, (CNS): composed of

the spinal cord & the brain, (PNS): composed of the afferent & efferent nerve fibers (neurons).

Afferent nerve fibers (sensory): connected to two cranial sister which can divide and end in the

(CNS).

Efferent nerve fibers (motor): divided into:

1- Somatic motor neurons, which control the voluntary movements (voluntary neurons).

2- Autonomic motor neurons, which are subdivided more to: Sympathetic, Parasympathetic,Enteric Nervous System (involuntary neurons).

Enteric Nervous System is related to the GIT, it separates the activities of the GIT away of the

CNS, and it is affected by sympathetic & parasympathetic innervations.

We have to differentiate between neurons & neuroglia (Glial cells):

*neurons will initiate and conduct impulses.

*while glial cells will support the neurons physically & metabolically >>> (homeostatically).

Neuroglia (glial cells) is divided into 4 types:

1- Astrocytes.

2- Microglia.

3- Oligodendrocytes.

4- Ependymal cells.

The exchange of materials (gases) and nutrients regarding the body (not in the brain), occurs

between the capillaries & the interstitial space, and it occurs mainly through the pores between

the cells of capillaries, meanwhile in the brain we have the Blood Brain Barrier (BBB), and the

capillaries of the brain are anatomically preventive, and physiologically restrictive.

Anatomically preventive: the Astrocytes forming tight junctions between the cells of the

capillaries.

Now the exchange of material (gases) & nutrients (in the capillaries) occurs all over the body down

concentration gradient, from concentration to concentration, and this is easy because the cell

membrane is composed of 1 layer.

In the brain the situation is deferent, we have to protect the brain from the chemical fluctuations

that occurs all over the body, which means if there is hyperkalemia in the blood it shouldnt affect

the brain.

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Thats why we have the Blood Brain Barrier (BBB) which act as protector to the brain. Now we

have tight junctions between the cells of capillaries preventing the exchange of components

(gases & nutrients) down concentration gradient, it is not easy for substances to cross this

barrier (BBB) because of the tight junctions between the capillaries.

Now the Astrocytes which are the major part of the neuroglia (glial cells), are involved in the

initiation of these tight junctions, and the establishment of specific channels and carriers for the

transportation of highly selected needed materials for the brain.

So the exchange in the brain is anatomically prevented because of the tight junctions (there are

no pores), and physiologically restricted (it allow what is needed and dont allow unneeded

materials).

We have to imagine the brain anatomically, from bottom to the top it is composed of cerebral

components.

At the bottom we have the Brain Stem, and it is composed of:

1- Medulla oblongata, 2- Pons, 3- Midbrain, three parts at the bottom.

Medulla oblongata which is the 1st part of the brain stem is continues with the spinal cord.

Then we will have the Cerebellum (), then the Forebrain which contains:

1- Diencephalon, which are:

a. Thalamus.

b. Hypothalamus.

2- Cerebrum, which is composed of:

a. Basal ganglia.

b. Cerebral cortex.

So basically we have brain cells graded from below to the top, Brain Stem (a. medulla oblongata, b.

pons, c. midbrain), Cerebellum, Diencephalon (a. thalamus, b. hypothalamus), and the Cerebrum (a.

basal ganglia, b. cerebral cortex).

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) in the+

(Kpotassiumconcentration of the electrolyte

medicalExtreme hyperkalemia is ablood is elevated.

due to the risk of potentially fatal abnormalemergency

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We have two head spheres (cerebral cortex), right one and left one, ( ), they

are connected via Corpus Callosum.

*Note: the more complex the stimuli (the input), the more # of interneurons are involved in the

integration process.

**For example: when you feel hot or cold, the thalamus will give you this information, it is hot or

cold, but if you are interested in the details i.e. where this hotness or coldness came from (the

source), more neurons will work (such as somatic sensory) in addition to the working one.

So multi-neurons are cooperating in the integration of a single stimulus sometimes.

**Another example: you saw a flower, so the visual area in your brain worked, you want to pick it,

the motor area in the parietal lobe worked, you want to smell it, the olfactory nerve worked etc.

Also in urinating, it is a rhythmic process, the center is in the spinal cord, and if you want to

inhibit it you have to give superior orders which are from the Brain Cortex.

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Now the Cerebral Cortex is composed of lobes:

1- Frontal lobe.

2- Occipital lobe.

3- Temporal lobe.

4- Parietal lobe.

Every lobe has its own specific function.

We have three functional areas in the Cortex:

1- Sensory area: receives and interpret sensory impulses, located posterior to the Central

Sulcus.

2- Motor area: control muscles movements, located anterior to the Central Sulcus.

3- Association area: integrate complex functions, like emotions,judging, memory etc.

Central Sulcus: it is deep infolding (groove), located between parietal lobe & frontal lobe.

Cortical areas of functional significance, and they are:

1-Primary motor area, which is located Pre-Central Gyrus in the frontal lobe, and it isresponsible for voluntary contraction of specific skeletal muscles.

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2-Premotor area (motor association area), which is located anteriorly to Primary motorarea, and its function is to communicate with the Primary motor area and other regions ofthe brain, so it controls learned, complex and skilled movements.

3-Primary somatosensory area, which is located Post-Central Gyrus in the parietal lobe,and its responsible for:

a. Proprioception: sensory impulses for the awareness of position.

b. Nociception: sensory impulses for the awareness of mechanical, thermal, chemical

changes (pain, pressure, temperature etc.).

4-Primary visual area: which is located in the occipital lobe, and it receives impulses from

retina.

5-Primary auditory area: which is located in the superior portion of the temporal lobe, it

receives impulses from inner ear, and interprets () the basic characteristics of sound.

6-Brocas area: which is located in the frontal lobe in one side only (usually left sidedominant hemi-sphere), and it is responsible for speaking ability (production of speech).

7- Wernickes area: This is located in the temporal lobe, at the junction of the parietal-

temporal & occipital lobes, and it is presented in one site only (usually left side dominant

hemi-sphere), and it is responsible for language comprehension (understanding bot

spoken & written speech).

Note: we have right and left hemi-spheres, if there is lesion in the somatosensory area at the

right hemi-sphere, left side of the body will be affected, and vice versa (opposite sites will be

affected), because there is a cross section () between the neurons at the corpus callosum, andas mentioned previously, it connects the two lobes.

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Thalamus and hypothalamus :-The Thalamus: - Two oval masses of gray matter which forms the wall of third ventricle.

Function of the Thalamus:

1) It is a main relay station for all Sensory impulses on their way from the spinal cord to

cerebellum and brain Stem to the cerebral cortex.2) So the preliminary processing of all sensory inputs occurs in thalamus.

Integration for the sub sensory input in the thalamus without the movement of the higher

sensors.

Hypothalamus is located inferiorly to the Thalamus

Function of hypothalamus: A major regulator of homeostasis..

Homeostasis regulating induces Regulate food intake

Controls hormone secretion Emotion and behaviorControls body Temperature

Effects autonomic nervous system

a)Heart rate b) Blood pressure Controls thirst and urine output

Two terms you must know:

1-Gray matter

2-White matter

Gray matter is composed mainly of neuronal cell body and dendrites

White matter is composed mainly of axons of the cell

Axons are covered by Myelinated sheath which are composed mainly of lipids

{ Whitish color of the white matter due to the myelinated sheat lipids of the axons }

*What is the function of myelin sheath ?

And why gray matter is composed of unmyelinated but white matter is composed of

myelinated cells ?

it increases the conductance of action potential , prevents leakage of impulse

-------------------------------------------------------------------------------------------------------------------------

The Basal Ganglia consists from a collection of neurons within cerebral white matter, they

are sub cortical masses

*The Doctor emphasized many times that Basal ganglia is in the Whit matter.

Wikipedia Says Along unmyelinated fibers, impulses move continuously aswaves, but, in myelinated fibers, they hop or "propagate bysaltation." Myelinincreaseselectrical resistanceacross the cell membrane.

Sub cortical means The portion of the brainimmediately below the cerebral cortex

http://en.wikipedia.org/wiki/Saltatory_conductionhttp://en.wikipedia.org/wiki/Saltatory_conductionhttp://en.wikipedia.org/wiki/Saltatory_conductionhttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Saltatory_conduction

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Basal ganglia composed of:-

a) Caudate nucleus

b) Put amen

c) globus pallid us

d) substantial nigra

e) Sub thalamic nucleus

Basal Ganglia's function:

Functions:

Inhibiting muscle tone throughout the bodyHelping monitor and coordinate slow, sustained contractions, especially those related to

posture and support

Selecting and maintaining purposeful motor activity while suppressing useless or unwanted

patterns of movement

Those patients who has basal ganglia disease (problems) Parkinson disease (Parkinsonism)when you Get old

Parkinson Disease : Deficiency of dopamine, an important neurotransmitter in the basal

nuclei

Wikipedia Says: Parkinsonism is a disorder characterized by muscular rigidity, Thisdisorder is due to a lack of dopamine in the basal ganglia. This lack of dopamine causesneuronal discharge abnormalities within the motor circuit.

Signs and symptoms:

Increased muscle tone, or rigidity Involuntary, useless, or unwanted movements, such as resting tremors (e.g., hands

rhythmically shaking)

Slowness in initiating and carrying out different motor behaviorsE.g. when someone drinks a cup of tea, Parkinson's patient doesnt' know when to stop, he

may reach his eyes instead his mouth { Timing } .

Diseases of brain

Neurologic diseases and psychological diseases

Related to neurons itself (nerve cell) or related to the neurotransmitters..

Any disturbances either Increase or decrease in the secretion of neurotransmitters in the

brain will create a problem.

Neurotransmitters are two kinds:

1) excitatory 2) Inhibitory neurotransmittersOver secretion of acetylcholine leads to Schizophrenia ( )

Schizophrenia is an organic defect*Organic defect is the disturbance in the neurotransmitter release eitherdecreasing or increasing.-Treatment of these disorders is very difficult, why?Because we cannot know the degree of the defect by ourselves.

Wikipedia Says: Schizophrenia is amentaldisordercharacterized by a disintegration ofthought processes and of emotional

responsiveness,Genetics, earlyenvironment,neurobiology,andpsychologicaland social processes appearto be important contributory factors.

http://en.wikipedia.org/wiki/Mental_disorderhttp://en.wikipedia.org/wiki/Mental_disorderhttp://en.wikipedia.org/wiki/Mental_disorderhttp://en.wikipedia.org/wiki/Mental_disorderhttp://en.wikipedia.org/wiki/Geneticshttp://en.wikipedia.org/wiki/Geneticshttp://en.wikipedia.org/wiki/Geneticshttp://en.wikipedia.org/wiki/Neurobiologyhttp://en.wikipedia.org/wiki/Neurobiologyhttp://en.wikipedia.org/wiki/Neurobiologyhttp://en.wikipedia.org/wiki/Psychologyhttp://en.wikipedia.org/wiki/Psychologyhttp://en.wikipedia.org/wiki/Psychologyhttp://en.wikipedia.org/wiki/Psychologyhttp://en.wikipedia.org/wiki/Neurobiologyhttp://en.wikipedia.org/wiki/Geneticshttp://en.wikipedia.org/wiki/Mental_disorderhttp://en.wikipedia.org/wiki/Mental_disorder

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Psychological disorder are divided into Neurosis and Psychosis

We must differentiate between neurosis and psychosis?!

$ Neurosis is mental disorders involving distress (Neurosis symptoms are stress , anxiety

,depression )Wikipedia Says A neurotic disorder can be any mental imbalance that causes or

results in distress. In general, neurotic conditions do not impair or interfere with

normal day to day functions, but rather create the very common symptoms of

depression, anxiety, or stress. It is believed that most people suffer from some sort of

neurosis as a part of human nature.

But psychosis is an Organic depression We must also differentiate between organic depression and active depressionOrganic depressions are Kinds of depressions that cannot be treated Such as Obsessive-

compulsive neurosis disorder.

Cerebellum: it is the underneath occipital lobe (located posteriorly), attached to the back of theupper portion of brain stem.The Cerebellum has two hemispheres

*Function: 1) Concerns in Subconscious control of motor activity includes a) maintaining bodybalance . b) Enhancing muscle tone . c) Coordinating skilled voluntary movements.

*such as dancing, not everyone can perform professional dance, or perform for example Boxing

movements

The cerebellum is responsible for learning these skills

2) Comparing between motor orders (intentions) of motor area with the performance of the

muscle this means

It corrects any error or deviation from the intended movement e.g. when you go up on stairs, if

you do that in the wrong way, by not raising your leg as much as required for one step, the

cerebellum corrects that to make you go up safely

3) The cerebellum can predict also the position of different parts of the body

4) It is also important to produce Smooth, precise movement and directs the movement.

http://en.wikipedia.org/wiki/Distress_(medicine)http://www.wisegeek.com/what-are-the-symptoms-of-depression.htmhttp://www.wisegeek.com/what-are-the-symptoms-of-depression.htmhttp://www.wisegeek.com/what-are-the-symptoms-of-depression.htmhttp://www.wisegeek.com/what-are-the-symptoms-of-depression.htmhttp://www.wisegeek.com/what-are-the-symptoms-of-depression.htmhttp://en.wikipedia.org/wiki/Distress_(medicine)

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The Cerebellum Damage

Alaxia Hypotonia

"Decrease in the muscle

tone"

"Not paralysis"

Delay in initiation of

voluntary

Movement

* Poor balance * clumsy movement

* Imbalance when eye

closed

* Dysmetra

* nystagmus

* Tremor "Intention

tremor"

Occurs during movement

*Cranial Nerves are very important to know, you must study (Slide 45) in the CNS Slides and

this is the Slide about Cranial Nerves .

The trigeminal nerve (V) is the most important Cranial nerves for us (Dentists) because it is

related to maxillofacial Surgery and head and neck anatomy.

"The Doctor said that we must only know the sensory and motor things for every Nerve, and

he won't ask us in the exam about the origin of these nerves.

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The peripheral nervous system composed of a) voluntary b) Involuntary

The voluntary which is the somatic motor which innervates muscles

Autonomic nervous system (ANS) is a part of the peripheral nervous system, which is

composed of

1) Sympathetic nervous system: is responsible for up- and down-regulating manyhomeostatic mechanisms in living organisms, Stress.

2) Parasympathetic nervous system: is responsible for stimulation of "rest-and-digest"

activities that occur when the body is at rest, including sexual arousal.

3)Enteric.

Sympathetic N.S: Nerve fibers of this system originate in the thoracic and lumbar regions of

the spinal cord.

So it originates from T1 to L2

Parasympathetic N.S: Nerve fibers originate from brain through cranial nerves III, VII, IX and

X and in the sacral region of the spinal cord.

*The Autonomic pathway from the brain and spinal cord to different tissues (target organ

consists of two nerve fibers)

For example

adrenergic receptor

Pre-ganglionic Sympathetic system Post-ganglionic

Ganglia

Somatic target tissue

Parasympathetic system Ganglia

Gland Muscarinic receptor

Brain spinal cord (CNS)

From the figure above we can figure out !!

We must differentiate between the parasympathetic and sympathetic and somatic.

In the sympathetic, we have ganglia, the Preganglionic fiber is short and thePostganglionic fiber is long.

And there is the target tissue (which is either a blood vessel or muscle), and it is far from

ganglia.

-The neurotransmitter released in both preganglionic sympathetic and preganglionic

parasympathetic nerve fibers is acetylcholine

http://en.wikipedia.org/wiki/Enteric_nervous_systemhttp://en.wikipedia.org/wiki/Enteric_nervous_systemhttp://en.wikipedia.org/wiki/Enteric_nervous_systemhttp://en.wikipedia.org/wiki/Enteric_nervous_system

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-While the neurotransmitter released in the postganglionic sympathetic nerve fibers is Nor-

epinephrine (Nor-adrenaline).

*These Nerve fibers are called (Adrenergic Nerve fibers).

-Neurotransmitter released in the postganglionic parasympathetic nerve fiber is

Acetylcholine.

*These Nerve fibers are called (Cholinergic Nerve fibers).

In the parasympathetic, we have ganglia, the Preganglionic fiber is long and thePostgangilionic fiber is short.

(Parasympathetic and Sympathetic are opposite in the length Pre & Post- ganglionic )

There is a Target cell, and it is near the ganglia

In the Somatic, there is no space for ganglia.

Function of ANS:

It regulates the involuntary activities (subconscious activities), these activities, we are

unaware about them and are not under control like digestion, sweating, heart andcirculatory regulation.

-Most of visceral organs are supplied by both sympathetic and parasympathetic nerve fibers

Such as :

Organ Sympathetic Stimulation Parasympathetic

Stimulation

Heart HR and force of

contraction

Airways Dilatation Constriction

GIT Motility ,contraction ofsphincters

Motility, relaxation ofsphincters

Eye Pupil dilatation Constriction

Liver cylycogenolysis lipolysis *************

saliva Thick saliva containing

mucus

Water saliva containing

enzyme

These organs are stimulated by both Sympathetic and Parasympathetic

Some organs are only stimulated by the sympathetic N.S such as sweat glands, kidneys,

adrenal medulla.

A basal activity exists in both systems

In certain conditions we need more activity of one system and decrease in the activity on the

other.

(Dominance of one system)

Parasympathetic sympathetic

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More

Sympathetic dominance in

condition of stress.

(Facing emergency or threat)

Parasympathetic dominance in quite, relaxed

Conditions (non-threatening circumstances)

more

That's all for Today's lecture..

Done by: 1) Khalid.Z.Mortaja

2) Maher.M.Khatib

Edited by : hashim gazo .

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Khalid: I dedicate this script to my brother, Salah Mortaja ,,, and Id like to thank him

for helping me in several things including the Anatomy scripts ,,, and wish him a

successful life.

And I cant forget my brother from another mother :P ,,, Maher Khatib (Abo-Munir)

,,, yis3ad rabbak man ,,, law biddi a7o6 ma3na tanee la kilmit kafo walla 3eer

a3ayyirha la abo al-khateeb.

Maher:"Me myself dedicate this Script to My brother "Saed jarrar" and to thank him

for helping me, not only in this script but in life also. And take the chance to tell him

and to my friend Ihab abu il 7amam,

And to a special person in my life that deserves all respect and love for standing

beside me all the Time.

And of course to My mate in this script and in everything , and like he said (my

brother from another mother :P) Khalid Mortaja

(Shanfiza ) abu il waleeeeeeeed !!

And from me and Khalid to our beloved friends: Dirgham , Ahmad Hassan, Hashim,

Akkad, Yahya, Wirrrrrrrrrrrrrrrr, Mo2nis, Yanal, Zezo , ..And Special thanks for Gayda'a Kana'an , Saved us with a better recorder..

Khalid: Finally, some sarcastic quotes Id like to share :P :

Experience is a wonderful thing. It enables you to recognize a mistakewhen you make it againPeople say that laughter is the best medicine your face must be curingthe world!

Maher: All I can say That Details make difference,

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