pen spot

The Effectiveness of The Variety of Clean Fluid to Let Disappear Ballpoint Pen Ink of Cloth


PROPOSAL
Presented to complete assignment of methodology course
Educated by Prof.Da.Herawati SusiloM.Si and Dr.Hadi Suwono,M.Si


by:
Susi Munawaroh (108341409786)
Rifqi Hardiana P. (108341410885)












BIOLOGY EDUCATION STUDY PROGRAM
BIOLOGY DEPARTMENT
MATHEMATIC AND SCIENCE FACULTY
STATE UNIVERSITY OF MALANG
November 2009

UNIT I
INTRODUCTION

1.1 Background
Most of people, especially students can’t free from spot of ballpoint pen ink, because ballpoint pen ink is fluid which used to support study process. Often when used it, ballpoint pen ink touch the cloth. And now not yet know what a substance which can disappear spot of ballpoint pen ink from cloth effectively.
A ballpoint pen (also eponymously known in British English and Australian English as a biro ) is a modern writing instrument. Ball point pen ink is not a something that you can usually remove with simple soap and water, but there is an easy and inexpensive way to remove pen ink from surfaces or clothing. (Helmenstine, 2009)
There are various of fluid which can dissolve the spot of ballpoint pen ink from cloth, they are petrol, citric acid, kerosin, detergen, and alcohol. To fit this facts, so necessary know what the clean fluid which most effective to disappear the spot of ballpoint pen ink from cloth.

1.2 Problematic formula
According to the background above, the problematic formula which appropriate are :
1. What a characteristic of ballpoint pen ink?
2. How comparasion of variety clean fluid to disappear the spot of ballpoint ink from cloth?
3. How disappear the spot of ballpoint ink from cloth?

1.3 Purpose
According to the problematic formula above, the purpose of experiment are :
1. To know the characteristic of ballpoint pen ink
2. To know the comparasion of variety clean fluid to disappear the spot of ballpoint ink from cloth.
3. To know how disappear the spot of ballpoint ink from cloth.

1.4 Adventages of experiment
The adventages of this experiment are :
1. Give information to society about characteristic of ballpoint ink
2. Give information to society about most effective clean fluid to disappear the spot of ballpoint ink from cloth.
3. Give information to society how disappear the spot of ballpoint ink from cloth.

1.5 Definition of variable
1. Independent variable : the kind of fluid
In this experiment, we use 4 different kind of fluid, there are alcohol,citric acid, petrol, and kerosin.
2. Dependent variable : The pen’s spot will be disappear.
The disappear can measure with paper level of whiteness. We can classify it with ranking (less white (1), white medium (2), and whiteness (3))
3. Control group: detergen
Detergen is fluid that often use to wash anything so it can be the control.

1.6 Hypothesis
In this experiment the hypothesis is: “ If the chemical activity of the fluid incresed, then the pen’s spot of cloth will be disappear.”











UNIT II
LITERATURE REVIEW

1. Ballpoint Pen Ink
Ballpoint pen (also eponymously known in British English and Australian English as a biro and pronounped /ˈbaɪroʊ/ BYE-roh in Britain and Australia but sometimes /ˈbɪəroʊ/ BEER-oh elsewhere, named after its credited, though contested, inventor László Bíró) is a modern writing instrument. A ballpoint pen has an internal chamber filled with a viscous ink that is dispensed at tip during use by the rolling action of a small metal sphere (0.7 mm to 1.2 mm in diameter) of brass, steel or tungsten carbide
The ink dries almost immediately after contact with paper. Inexpensive, reliable and maintenance-free, the ballpoint has replaced the fountain pen as the most popular tool for everyday writing. When ballpoint pen ink touch the cloth, to difficult to disappear it with simple soap and water. (Helmenstine, 2009)
Ink is a complex media, contain of solvent, pigment, dig, resin, and pelumas, sollubizer (material which form polar polymer ions with waterproof resin), surfactant (wet element which drop surface pressure a fluid and between two fluid).

2. Petrol
Petrol is a petroleum-derived liquid mixture, primarily used as fuel in internal combustion engines. It is also used as a solvent, mainly known for its ability to dilute paints. Gasoline contains about 32.0 MJ/L (9.67 kWh/L, 132 MJ/US gal or 36.6 kWh/US gal). This is an average; gasoline blends differ, and therefore actual energy content varies from season to season and from batch to batch, by up to 4% more or less than the average, according to the US EPA. On average, about 19.5 US gallons (16.2 imp gal; 74 L) of gasoline are available from a 42-US-gallon (35 imp gal; 160 L) barrel of crude oil (about 46% by volume), varying due to quality of crude and grade of gasoline. The remaining residue comes off as products ranging from tar to naptha. It consists mostly of aliphatic hydrocarbons obtained by the fractional distillation of petroleum, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating.

3. Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin, is a combustible hydrocarbon liquid. The name is derived from Greek keros (κηρός wax). The word Kerosene was registered as a trademark by Abraham Gesner in 1854 and for several years only the North American Gas Light Company and the Downer Company (to which Gesner had granted the right) were allowed to call their lamp oil kerosene, It eventually became a genericized trademark.
Kerosin is non polar solution. Kerosene is a thin, clear liquid formed from hydrocarbons, with density of 0.78-0.81g/cm3. Kerosene is obtained from the fractional distillation of petroleum between 150 °C and 275 °C, resulting in a mixture of carbon chains that typically contain between 6 and 16 carbon atoms per molecule.[5] The flash point of kerosene is between 37 and 65 °C (100–150 °F) and its autoignition temperature is 220 °C (428 °F).[6] Kerosene is insoluble in water (cold or hot), but miscible in petroleum solvent.

4. Citric acid
The particular variety of Citric Acid offered by Mountain Rose Herbs is USP grade and is soluble in water and very soluble in alcohol. Can be used for both cosmetic and culinary use.
Citric acid is a very useful and effective preservative, obtained from naturally occurring organic acids. It exists in many different fruits and vegetables, but is especially concentrated in lemons and limes. Although it is also produced in refineries by using cane sugar, molasses, and dextrose, the citric acid stocked by Mountain Rose Herbs comes from the fermentation of crude fruit sugars. Citric acid is used extensively in the food, beverage, cosmetic, and pharmaceutical industries. It has been recognized as safe by all major national and international food regulatory agencies, and is also approved by the US Food and Drug Administration and in Europe for use in food. Citric acid is used for many different reasons, including (but not limited to): Antioxidant and preservative properties, prevents rancidity and bacteria growth, astringency and Acidity, used in sourdough bread for an extra tart taste (known as "sour salt" among bakers), adjusts pH, stabilizes the ingredients, color, taste, and flavor of a product, rapidly biodegradable, readily metabolized and eliminated from the body
Undeniably, citric acid is a very important ingredient for use in natural body care and cosmetic recipes. Not only does citric acid have many varied applications and uses, but it has also been approved by the FDA and other food regulatory agencies. Furthermore, since citric acid is present in almost every life form, it is consequently easily metabolized and eliminated from the body.
Citric acid is often a base ingredient in bath bomb recipes, and is the agent responsible for the "fizzing" action. In the majority of body care recipes, it is used in small proportions, usually not making up more than 0.5% of the total solution. At room temperature, citric acid is a white powdered form. However, it may be dissolved and easily incorporated into your recipes by heating it in a liquid mixture to a temperature above 74 degrees Celcius.

5. Alcohol
Alcohol is created when grains, fruits, or vegetables are fermented. Fermentation is a process that uses yeast or bacteria to change the sugars in the food into alcohol. Fermentation is used to produce many necessary items — everything from cheese to medications. Alcohol has different forms and can be used as a cleaner, an antiseptic, or a sedative.
So if alcohol is a natural product, why do teens need to be concerned about drinking it? When people drink alcohol, it's absorbed into their bloodstream. From there, it affects the central nervous system (the brain and spinal cord), which controls virtually all body functions. Because experts now know that the human brain is still developing during our teens, scientists are researching the effects drinking alcohol can have on the teen brain.





UNIT III
EXPERIMENTAL METHOD

A. Kind of experiment : Quantitative experiment
B. Equipments and Materials
-Tools:
Boils (15)
Scissor (1)
Spoon (5)
Paper level of whiteness (1)
Beaker Glass (1)
-Materials:
Kind of fluid
Kerosene (6 spoonfull)
Petrol (6 spoonfull)
Alcohol (6 spoonfull)
Detergen liquid (as a control) (6 spoonfull)
Citric acid (50 gr) + 90ml water
Water (1500ml)
Cloth (10cm x 10cm) (15 pieces)

C. Procedure:
1. Prepare tools and materials
2. Make a citric acid liquid 50 %
a. Enter 50 gr of citric acid into beaker glass and add water until 100ml
b. Then mix it with spoon
3. Cut the cloth become 12 piece with a scissor (size of each piece is 10cm x 10cm)
4. Give ballpoint pen ink’s spot to each clothes ( the spot is dot with same diameter 0,5cm)
5. Available 15 boils
6. Enter 1 cloth (that give a dot spot) into each boil
7. Enter alcohol into 3 boils which each boil is 2 spoonfull
8. Enter petrol into 3 boils which each boil is 2 spoonfull
9. Enter kerosene into 3 boils which each boil is 2 spoonfull
10. Enter citric acid liquid 50 % each 3 boils which each boil is 2 spoonfull
11. Enter detergen into 3 boils which each boil is 2 spoonfull
12. Let after it for one hour
13. And then take it
14. After that rub the each cloth
15. Give each cloth with 100ml water
16. Dry and compare it
17. Put in the data on table which available.

D. The way to collect data and experimental instrument
We measure the disappear of cloth with paper level of whiteness. So we must compare the cloth before. After that we can classify it with ranking (less white, white medium, and whiteness).
The table available:
Trials
3 times Control
(detergen) Kind of fluid
Alcohol Petrol Citric acid Kerosene
1 1 cloth 1 cloth 1 cloth 1 cloth 1 cloth
2 1 cloth 1 cloth 1 cloth 1 cloth 1 cloth
3 1 cloth 1 cloth 1 cloth 1 cloth 1 cloth

E. Analysis data
We analize the data of experiment with t- test. T test is use for comparing the data which have more than 2 treatment.





UNIT IV
REFERENCE


Anonim, 2009. (online)
http://en.wikipedia.org/wiki/Ballpoint_pen, diakses 13 November 2009.

Helmenstine, Anne Marie. 2009. (online)
http://kidshealth.org/teen/drug_alcohol/alcohol/alcohol.html. diakses 13 November 2009.

Anonim, 2009. (online)
http://id.wikipedia.org/wiki/Alkohol. diakses 13 November 2009

Anonim, 2009. (online)
http://en.wikipedia.org/wiki/Citric_acid, diakses 13 November 2009.

Anonim, 2009. (online)
http://en.wikipedia.org/wiki/The fuel and industrial solvent, diakses 8 November 2009.

Nervous System

UNIT I
INTRODUCTION


1.1 Background
There are so many materials which have to be mastered by student in histology lesson, including Nervous System. In studying this material, student must learn deeply with the right concept. Many ways can use to support the learning process of this material, like make a paper. That is the reason why this paper is made. We make this paper not only to complete the assignment of Histology, but also to sharper our understanding of Nervous System material. In Nervous System divided into two part, there are Central Nervous System and Peripheral Nervous System. It contains the majority of the nervous system and consists of the brain and the spinal cord. In Peripheral Nervous System divided into Autonomic Nervous System and Somatic Nervous System . Together with the peripheral nervous system it has a fundamental role in the control of behavior. Because of the completable of these unit, So we must know and identify about apart of our self body that have many function in our body system. In this unit we just talk about Central Nervous System, because it is the main part of Nervous System that must known. The function of Central Nervous System is to receive and integrate incoming information (stimuli) corcening our internal and external environtment received from sensory receptors. Motor impuls are generated and discharged to effector organs (muscle and glands) for appropriate action, or the information may be stored as memory for future reference. Central Nervous System divided into Spinal cord and Brain. In each part have mainly function that very important in our body selves.

1.2 Problematic Formula
According to the background above, the problematic formula which appropriate are:
1. How is the histological structure of Central Nervous System?
2. How is the histological element of the Central Nervous System?
3. How is the histological structure of Spinal cord?
4. How is the histological structure of Brain?
5. How is the description of the Neuroglia?
6. How is the description of the Meninges?
7. How is the descriotion of the Cerebrospinal Fluid?

1.3 Purpose
According to the problematic formula above, the purpose of experiment are:
1. To Explain about histological structure of Central Nervous System.
2. To Explain about histological element of the Central Nervous System.
3. To Explain about histological structure of Spinal cord.
4. To Explain about histological structure of Brain.
5. To describe of the Neuroglia.
6. To describe of the Meninges.
7. To describe of the Cerebrospinal.


UNIT II
EXPLANATION

The nervous systems, together with the hormones secreted by endocrine system, maintain a balance among the various activities of the body, called homeostasis. It is the critical balance that prepares responses the body must make in response to external environmental stimuli. The nervous system is widespread throughout the body. Its interconnections are so extensive that nerve impulses can be transmitted along the network from one end to the other. Hence, an activity in one body region is likely to influence activity in other regions. Obviously, the functions can be very different, varying from a simple two neuron reflex to the complex special sense of hearing and seeing. (Telford, 1995)
The nervous system is derived from embryonic ectoderm through two rudiment, they are neural tube and the neural crest. The tube has its beginning at the neural plate which forms a thickened band of ectoderm along the midline of the embryo. The edge of the plate becomes depressed to form the neural tube. The anterior part of the tube enlarges to form the brain, whereas the smaller diameter posterior portion forms the spinal cord. (Telford, 1995)
The neural crest appears, just before the closure of the neural tube, as a cluster of specialized cells along the neural ridges. When the neural tube closes, the neural crest cells do not fuse with either the neural tube or the surface ectoderm, but remain between the structures. The principal derivatives of the neural crest are the spinal and cranial ganglia. (Telford, 1995)
The nervous system devided into two part, there are Central Nervous System and Peripheral Nervous System.

Central Nervous System
The central nervous system (CNS) is the part of the nervous system. In vertebrates, the central nervous system is enclosed in the meninges, connective tissue, and is protected by bone (skull and vertebral column). It contains the majority of the nervous system and consists of the brain and the spinal cord. Together with the peripheral nervous system it has a fundamental role in the control of behavior. The central nervous system is contained within the dorsal cavity, with the brain in the cranial cavity and the spinal cord in the spinal cavity. The brain is protected by the skull, while the spinal cord is protected by the vertebrae. (Wikipedia, 2009)
The function of central nervous system is to receive and integrate incoming information (stimuli) concerning our internal and external environment received from sensory receptors. Motor impulse are generated and discharged to effector organs (muscle and glands) for appropriate action, or the information may be stored as memory for future reference. (Telford, 1995)










Histological Structure of Central Nervous System
The histological element of the central nervous system consists of:
a. Neuron
Neuron is cell body, in the spinal cord located in a longitudinal, in the center of the cord it has H-shaped column, while in the brain, they are either in clusters (nuclei) deep in the brain or in layers (laminae) in the superficial cortex.
b. Glia
Glia is nonneunoral cells that are supportive or insulating elements throughout the central nervous system. The glial cells, derived from neuroectoderm, serve roles of connective tissue within the CNS tissue. Three types are found: (1) microglia, which represent macrophages of the CNS, (2) oligodendrocytes, which myelinate the axons within the CNS and, (3) astrocytes, which are a fibroblast-like supportive cell. These cells are characterized as fibrous astrocytes with unbranched processes and protoplasmic astrocytes with branched processes.
c. Nerve fiber
Nerve fiber is mostly long axons which may be myelinated or non-myelinated. They traverse and connect various regions of the brain and spinal cord. Most of the fiber is in definite bundles called tracts. These bundles are encapsulated in fibroconnective tissue in a manner similar to that seen in muscle tissue. Entire nerve bundles are surrounded by the epineurium (Nerve Bundle 1). Branching from the epineurium and dividing the nerve bundle into fascicles is the perineurium (Nerve Bundle 2). Finally each individual axon is surrounded by the endoneurium (Nerve Bundle 3).
d. Accessory structures
It is support and nourish the nervous elements are the investing meninges, abundant blood vessels, and the cerebral spinal fluid (CSF) in spaces, or reservoirs, called cisternae and ventricles.

-Central nervous system consists of the brain and spinal cord. The brain and spinal cord are each divided into gray and white matter.

a. Gray Matter
Grey matter is a major component of the central nervous system consisting of neuronal cell bodies, neuropil (dendrites and both unmyelinated axons and myelinated axons), glial cells (astroglia and oligodendrocytes) and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts. The color difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually has a grey-brown color which comes from capillary blood vessels and neuronal cell bodies.
Grey matter is distributed at the surface of the cerebral hemispheres (cerebral cortex) and of the cerebellum (cerebellar cortex), as well as in the depths of the cerebrum (thalamus, hypothalamus, subthalamus, basal ganglia - putamen, globus pallidus, nucleus accumbens, septal nuclei), cerebellar (deep cerebellar nuclei - dentate nucleus, globose nucleus, emboliform nucleus, fastigial nucleus), brainstem (substantia nigra, red nucleus, olivary nuclei, cranial nerve nuclei) and spinal grey matter (anterior horn, lateral horn, posterior horn).
The function of grey matter is to route sensory or motor stimulus to interneurons of the Central Nervous System in order to create a response to the stimulus through chemical synapse activity. Grey matter structures (cortex, deep nuclei) process information originating in the sensory organs or in other gray matter regions. This information is conveyed via specialized nerve cell extensions (long axons), which form the bulk of the cerebral, cerebellar, and spinal white matter. (Wikipedia. 2009)

b. White Matter
In white matter, parallel fascioles of myelinated axons dominate an exhibit a white, glistening appearance in the fresh condition. There are relatively few capillaris and very little extracelluler space. Because the function of white matter is largely conductive. It has considerably less metabolic activity. It differ greatly from gray matter by having no synapses no dendrites, and a limited blood supply.


-Spinal Cord
The Spinal Cord is connected to the brain and is about the diameter of a human finger. From the brain the spinal cord descends down the middle of the back and is surrounded and protected by the bony vertebral column. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae.
A typical cross section of the spinal cord is demarcated into an outer thick zone of white matter and an inner butterfly or H-shapped zone of gray matter. Near the center of the crossbar of the H is the small central canal lined with ependymal cells, a type of glia cell. On each side of the cord, the gray matter extends caudally and rostrally as two vertical columns called the dorsal (posterior) and ventral (anterior) horns. A small lateral horn is also seen in the thoracic and upper lumber regions.
There are three major types of the spinal gray matter, (1) the large, stelatte motor cells in the ventral horns, (2) the small and medium sized sympathetic efferent neurons in the lateral horns, and (3) the medium sized sensory neurons in the dorsal horns. All of these cells are confined to layers called laminae.
The white matter of the spinal cord consist of bundles of axons having spesific functions either motor of sensory, example pain, touch propioception. There are three of these large fibers columns or funiculi (L., cord), named their position example dorsal, ventral, lateral. Each faniculus is subdivided into smaller nerve bundles, the fasciculi, or tract. From the named of the tract, one can tell the location of the cells of origin and the termination of the fibers. For example, in the corticospinal tract, the cell bodies are in the cerebral cortex, and their axons end synaptically on neurons in the spinal cord.
While the pattern of gray and white matter is constant, their relative proportions vary at various levels. The greatest amount of gray matter is found in the cervical and lumbar enlargements of the cord because of the marked increase of neurons that are needed to serve the upper and lower limbs. The white matter increases in a caudal to rostral direction because the ascending pathways, connecting the spinal cord with the brain, are constantly recruiting fibers as they approach the brain. Furthermore, the axons of the descending tract gradually leave the tract to terminate in synapsea on the motor cells of the gray matter (ventral horn) of the cord. Recall that, in contrast to the gray matter, white matter contains only axons and glial cells.

-Brain
Brain is central nervous system. Brain located in cranium.The function of brain is manage most of movement, behavior and function of homeostatic like as pulse rate, blood pressure, and the other.
. Brain is subdivided into the large cerebrum, the much smaller cerebellum (meaning small brain), and inferiorly situated, funnel shaped brain stem. The latter is composed of nerve tract entering and leaving the brain as well as nuclei sub serving various reflect function

1. Cerebrum
The cerebrum is divided into two equal hemispheres by a deep, longitudinal fissure that contains the falx cerebri, a vertical extension of the dura meter. The cortex (gray matter) is highly convoluted, i.e., thrown into deep folds, which greatly increase its surface area. The convolutions are called gyri and the intervening depressions are sulci.
Histologically the cerebral cortex shows six ill defined layer or zone that vary In their cytoarchitecture from area to area of the brain. Three morphologically different cell types make up most of the neurons, i.e.,stellate or granular , fusiform, and phyramidal . By far the most conspicuous are the various sized phyramidal cells
All phyramidal cells have an apical dendrite that project toward the outer surface of the cortex. Its axon, emerging from the based of the phyramid, penetrates the deeper layers of the cortex eventually to form the efferent pathways of the brain in the white matter of the cortex








The Layer of Cerebral Cortex
The different cortical layers each contain a characteristic distribution of neuronal cell types and connections with other cortical and subcortical regions. One of the clearest examples of cortical layering is the stria of gennari in the primary visual cortex. This is a band of whiter tissue that can be observed with the naked eye in the fundus of the calcarine sulcus of the occipital lobe. The Stria of Gennari is composed of axons bringing visual information from the thalamus into layer four of visual cortex. The neurons of the cerebral cortex are grouped into six main layers, from outside (pial surface) to inside (white matter).
1. The molecular layer I, which contains few scattered neurons and consists mainly of extensions of apical dendritic tufts of pyramidal neurons and horizontally-oriented axons, as well as glial cell. Some Cajal-Retzius and spiny stellate neurons can be found here. Inputs to the apical tufts are thought to be crucial for the ‘‘feedback’’ interactions in the cerebral cortex involved in associative learning and attention. While it was once thought that the input to layer I came from the cortex itself, it is now realized that layer I across the cerebral cortex mantle receives substantial input from ‘‘matrix’’ or M-type thalamus cells (in contrast to ‘‘core’’ or C-type that go to layer IV
2. The external granular layer II, which contains small pyramidal neurons and numerous stellate neurons
3. The external pyramidal layer III, which contains predominantly small and medium-size pyramidal neurons, as well as non-pyramidal neurons with vertically-oriented intracortical axons; layers I through III are the main target of interhemispheric corticocortical afferents, and layer III is the principal source of corticocortical efferents
4. The internal granular layer IV, which contains different types of stellate and pyramidal neurons, and is the main target of thalamocortical afferents from thalamus type C neurons. as well as intra-hemispheric corticocortical afferents
5. The internal pyramidal layer V, which contains large pyramidal neurons (such as the Betz cells in the primary motor cortex); it is the principal source of subcortical efferents
6. The multiform layer VI, which contains few large pyramidal neurons and many small spindle-like pyramidal and multiform neurons; layer VI sends efferent fibers to the thalamus.establishing a very precise reciprocal interconnection between the cortex and the thalamus
It is important to note that the cortical layers are not simply stacked one over the other; there exist characteristic connections between different layers and neuronal types, which span all the thickness of the cortex. These cortical microcircuits are grouped into cortical columns and minicolumns, the latter of which have been proposed to be the basic functional units of cortex.]The functional properties of the cortex change abruptly between laterally adjacent points; however, they are continuous in the direction perpendicular to the surface. Later works have provided evidence of the presence of functionally distinct cortical columns in the visual cortex, auditory cortex and associative cortex.







Three drawings of cortical lamination each show a vertical cross-section, with the surface of the cortex at the top. Left: nissl- stained visual cortex of a human adult. Middle: Nissl-stained motor cortex of a human adult. Right: golgi stained cortex of a 1½ month old infant. The Nissl stain shows the cell bodies of neurons; the Golgi stain shows the dendrites and axons of a random subset of neurons

2. Cerebellum
The cerebellum is divided into right and left hemispheres, which are separated by a wormlike, segmented band of gray matter called vermis. The surface of the hemispheres is thrown into many thin, parallel folds or leaflets called folia. A thin cortex of gray matter covers the folia. Collections of neurons are buried in the underlying white matter, constituting the cerebellar nuclei.
A section through the cerebellar cortex reveals a trilaminar structure. It has outer molecular layer consisting of a few, small, basket type and stellate type neurons, myriad parallel fiber derived from granule cell and a massive dendritic arborization largely arising from the deeper purkinje cells. The intermediate layer is the purkinje layer, consisting of single layer of large purkinje cells whose cells bodies rest on the innermost granular layer. The purkinje cell has a large, prominent, flask-shaped cell body with a clear vesicular nucleus. Many nissl granules are scattered throughout the cytoplasm. Its most distinctive feature , however ,is its elaborate ,profusely branching, three like dendritic arbor ,which project into the molecular layer.
The innermost granular layer is the most conspicuous layer of the cerebellar cortex because it consists of large populations of closely packed, small granular cells whose nuclei essentially fill the cell. Under low power, the resemble lymphocytes.


3. Brain stem
The brain stem houses the main sensory and motor tract of the brain. They are collected and concentrated into this cylindrical mass of white matter, which tapper caudally to form the spinal cord. The cerebellum rest astride the central portion of the brain stem, called the spons. Other part are medulla oblongata located between the spinal cord and the spons, and the mid brain, situated rostral to the pons. The diencephalon extending rostrally from the mid brain.
Histological the brain stem exhibits a variety of neural structure . It is the funnel through which all the nerve pathways between the cerebrum and spinal cord must pass. Practically all of the tracts are composed of heavily myelinated fibers. It is in the brain stem that most of the cranial nerves arise or terminate. Therefore in the gray matter, where these event take place neuron are sequestered in clusters.

-Neuroglia
About 70-80% of all cells of the CNS are non-nervous; they’re mostly supportive cells, not neurons. Collectively they are called glial cells or neuroglia. As reinforcing cells, their function similar to connective tissue cells in other parts of the body. Neuroglia include astrocytes (protoplasmic and fibrous), oligodendroglia, microglia and ependyma.


a. Astrocytes
The largest of neuroglia, the star-shaped astrocytes (Gk., astron, star), are two types: protoplasmic or mossy and fibrous or spider-like. They are probably the same cell type, merely representing functional differences as reflected in their structural variation. Astrocytes are about 8-10 m in diameter.
Protoplasmic astrocytes are found chiefly in the gray matter. They have a rather large, round, light-staining nucleus surrounded by abundant granular cytoplasm. Many cytoplasmic processes terminate as expanded endings, called perivascular feet, which attach to the basal lamina of capillaries.
Fibrous astrocytes (spider cells) are found mainly in the white matter. As their name implies, they have long, thin, sparsely branching processes that extend considerable distances from the body. Otherwise they are similar to protoplasmic astrocytes.


b. Oligodendroglia
The oligodendrocyte, found in both white and gray matter, is the most common of the supporting elements of the CNS. It has a smaller cell body than astrocytes (measuring 6-8 m in diameter) and contains a small, often eccentric, dark nucleus with abundant heterochromatin. As its name implies, it has only a few (Gk., oligo, few) processes. It has considerably less cytoplasm and is more granular in appearance than the astrocytes. The oligodendrocytes do not have perivascular feet, yet their bodies may rest on capillaries. They are three types of oligodendrocytes; perivascular oligodendrocytes, perineural glia or satellite cells and interfascicular cells.



c. Microglia or Mesoglia
Microglia also called mesoglea because it derived from mesoderm. Microglia is the smallest of the glial cells with 5-7 μm in diameter. Their nuclei are small, irregular in shape and stain deeply. The cells have very limited, granular cytoplasm and only a few stubby, twisted processes. They make up about 4-5% of the total population of glial cells in the white matter but about 18% in the gray matter of the cerebral cortex. Their structural characteristics include the many dense inclusion bodies, lysosomes, and lipofuscin granules, which are suggestive of the cell’s phagocytic activity. The rER has long, attenuated cisternae, as contrasted to the short cisternae of oligodendrocytes.
Microglia is phagocytic cells, a part of the macrophage (reticuloendothelial) system. When engorged with cellular debris, principally degenerating myelin, they are called gittter cells. Their numbers greatly increase following the damage to the CNS. They may be brought to the site of injury by the general circulation or by migration from other areas of the CNS by amoeboid movement.










Source : www.mda/alsnewsmagazine.com
-Meninges
Bony encasement (the skull and vertebral column) protect the CNS from external trauma as well as by three membranous investments, the meninges. These fibrous coverings are the outermost, robust dura mater; the middle, spider web-like arachnoid; and the innermost, delicate, vascular pia mater. The three layers enclose the brain and spinal cord. They also sheathe the cranial nerves as they leave the cranium and the spinal nerves as they leave the vertebral canal.



Source: www.medical-look.com

a.Dura Mater
The cranial dura is a tough, relatively thick collagenous sheath consisting of two layers: (1) an outer, dense connective tissue, the endosteal layer, adheres to the inner surface of the bones of the skull. It is well supplied with blood vessels and nerves. (2) An inner meningeal layer consists of a thinner fibrous tissue membrane, which is covered on its inner surface by a single layer of flat, mesothelial cells. Thees two layers separate from each other to the certain locations to form the extensive venous (dural) sinuses.
The dura also sends out extensions that form partitions for the brain. The largest of these is the sickle-shaped falx cerebri, which extends along the superior longitudinal fissure and partially separates the left and right cerebral hemispheres. An extension of the dura as a thick septum between the cerebellar hemispheres is the falx cerebelli. Separating the cerebellum and cerebrum is another extension of the dura, the tentlike tentorium cerebelli. At its anterior aspect is an oval gap, the tentorial notch, which allows the brain stem to pass from the undersurface of the cerebrum into the posterior cranial fossa.
The spinal dura is a continuation of the inner layer of the cranial dura. From its attachment to the margins of the foramenmagnum of the skull, it descends as a closed tube to surround the spinal cord. It terminates as the coccygeal ligament that invests the filium terminale, the filamentous ending of the spinal cord.

a. Arachnoid
The arachnoid is a delicate, nonvascular membrane immediately beneath the dura. It has two components: (1) a thin, connective tissue component on contact with the dura and (2) a network of delicate trabeculae, which are covered with flat or low cuboidal epithelium. The trabeculae expand into the rather large space between the connective tissue and the underlying pia mater. This cavity is the important subarachnoid space, which is filled with CSF.
In some areas adjacent to the venous dural sinuses, the arachnoid perforates the dura mater to open into the venous sinuses. These protrusions, carrying a central core of trabeculae, are the arachnoid villi, which function to transfer the CSF back into the blood stream.

b. Pia Mater
The pia mater is a thin, highly vascular sheath that adheres closely to the brain and spinal cord. It follows all of their surface irregularities. Therefore, unlike the dura and arachnoid, the pia closely covers the convolutions (gyri) of the brain and extends into the depths of the sulci. As blood vessels penetrate the brain and spinal cord they carry the pia with them for a short distance, creating a perivascular space.
The pia mater consists of two poorly defined layers. The inner, thinner layer of reticular and elastic fibers is firmly attached to the underlying nervous tissue. The more superficial layer receives fibrous attachments (trabeculae) from the arachnoid. Its external surface is a single layer of squamous cells of mesodermal origin. This cellular covering is continuous with cells covering the arachnoid. Because both the pia and the arachnoid are so closely related, they are often described as a single structure, the pia-arachnoid membrane, or leptomeninx.
-Cerebrospinal Fluid
Most of the CSF is produced in choroids plexuses in the ventricles of the brain. The remainder of the fluid, perhaps as much as 40%, is formed at other sites, e.g., at the blood vessels, and the ependymal lining cells of the ventricles and spinal canal.
a. Ependymal Cells
In embryonic development, the brain and spinal cord develop as a hollow tube. Lining this neural tube are primitive neuroopithelial cells that later persist as cuboidal ependymal cells, a type of neuroglia. They line the four ventricles of the brain and the central of the spinal cord and cover the coroid plexuses.
Many of these cells have an abundance of microvilli and one or two cilia on their luminal surface. The presence of cilia is not unexpected because all the cells had cilia during some stage in their development. The basal end of these ependymal lining cell do not rest on a basement membrane, instead, the base is tapered to form a single, branched process that extends into the underlying nervous tissue, in thin region of the brain, some of these processes may extend to the external surface of the brain. Along with other glial cell processes, they contribute to the formation of the glia limitans.
Transmission electron micograph of the lining ependymal cells reveal large accumulations of mitochondria in the apices of the cells. The other cell organelles are similar to the astrocyte, e.g., limited rER and ribosome, small Golgi complexes, and many bundles of neurofilaments; each filament is about 6-10 mm in diameter.
In certain region of the ventricles of the brain, the lining ependymal cells cover tufts of capillaries, called choroids plexuses. This special layer of ependyma is the choroids plexus epithelium, which is involved in the production of the CSF.

b.Choroids plexuses
The choroids plexuses are delicate capillary network formed by invaginations of the pia mater called thela chorioidea. As the plexuses invaginate into the ventricles, they are convered by a layer of cuboidal epithelium, the ependymal cells that line the ventricles (brain cavities). This epithelium shows evidence of high metabolic activity, involving the expenditure of energy in the production of CSF. Such cytological characteristic of the epithelium include numerous mitochondria; abundance cytoplasm; and large, clear, vesicular nucleus. Also, the plasma membrane of the free surface of these cells has irregular microvilli, suggesting an absorptive function.
Eventually, the CSF leaves the interior of the brain by way of three foramina to enter the subarachnoid space surrounding the brain. The fluid then flow down the subarachnoid space surrounding the spinal cord. Thus, the CSF serves as an effective fluid buffer or cushion for the CNS, protecting it against sudden movements of the head and body.
As the fluid diffuses over the brain, it escapes from the subarachnoid spce by passing through villi that perforate the dura into the dural venous sinuses of the brain. The arachnoid villi became hyperthrophied with age and are then called Pacchionian bodies or arachnoid granulations. They may be of sufficient size to produce a pitting of the cranial bones, which can be seen in the dried skull.
c. Blood-Brain Barrier
When certain drugs, pigments, or dyes are administered intravenously to animals, these substances do not enter the tissues of the brain or spinal cord, yet they penetrate most other tissues of the body. Such absorptions suggest the presence of barrier between the capillaries of the CNS and the surrounding nervous tissue, i.e., a blood-brain barrier.
It was not until EM studies were available, however, that the elements of the barrier were identified. They include the presence of (1) many tight junctions between adjacent endothelial cells that line the continuous-type capillaries of the CNS, (2) a well developed basal lamina surrounding these capillaries, and (3) the extensive covering of the external surface of the capillaries by myriad end-feet process from atrocytes. Such a physiohistologic barrier normally allows only O2, CO2, and small nutrient molecules to pass, which sustain the easily damaged neurons and delicate glial cells.

COMPARISON OF LAYERS IN CENTRAL NERVOUS SYSTEM
LAYER NUMBER NAME NERVE CELL BODIES PROCESSES AND SYNAPSES
Cerebrum
I
Molecular or Plexiform
Only few cells, mostly horizontal cells (of Cajal) and a few Golgy type II cells
Terminal dendrites of fusiform and pyramidal cells from deeper layers, also axonalsynapses with neuron possessing ascending axons, i.e.,Martinotti cells
II Outer Granular Many small pyramidal and stellate cells, which appear as granules, called small granulle cells Dendrites of both cell types terminate here, whiletheir axon descend to deeper layers; axons of deep Martinotti cells synapse here
III Outer Pyramidal Most cels are medium-sized pyramidal cells; others are large pyramidal and Martinotti cells Apicaldendrites extend into molecular layer;axons descend to synapse in deeper layers
IV Inner Granular Chiefly small, stellate cells that resemble granules under low magnification Axons of smaller cells largely remain in layer;axons of larger cells descend to synapse in deeper layers
V Inner Pyramidal or Ganglionic Principally large and medium-size pyramidal cells, in motor cortex giant cells of Betz are prominent Axons pass into white matter,while apical dendrites ascend intomolecular layer or may arborize within layer
VI Fusiform and multiform Fusiform (spindle) cells dominate; their long axes are perpendicular to cortical surface Apical dendritesof smaller spindlecells arborizewhitin layer, other ascend into upper layers; allaxons of spindle cells enter white matter;axons from cells of other layers synapse here
Cerebellum
I
Molecular
(outer)
Few small basket and stellate cells
Theirdendrites arborize in layer, extensive Purkinje cell dendritic ramifications dominate area; T-shaped axons of granule cells synapse here
II Purkinje
(middle) Single row of large, flask-shaped Purkinje cells associated with afew small, basket cells and Golgi type II cells Massive, treelike dendrites extend into molecular layer; Purkinje axons extend trough the inner granular layer to enter whitematter
III Granular
(inner) Numerous,closely packed dark-staining, small granule cells, some GolgitypeII cells inupper partr of layer Thin, unmyelinated axons of granulecells ascend into molecular layer,their short dendrites terminatein glomeruli near cells bodies;dendritesog golgi cells terminatein molecular layer
Spinal Cord
I

White matter
Virtually none
Parallelbundles of myelinated axons fill field; essentially no dendrites or synapses present
II Gray matter Three types of moltipolar neurons: (a) Large,stellate motor cells in ventral horn; (b) small,stellate, internuncial cells between ventraland dorsal horns;(c) medium-sized stellate sensory cellsin dorsal horns Abundance of fine unmyelinated axons; frequent axonic synaptic terminal; extensive dendritic plexuses surround nerve cells bodies

Peripheral Nervous System
Afferen and efferent fiber
-The Neuron Doctrine
-The Neuron
Morpholigal Classification
Perikaryon
Cell Processes
Axon
Dendrites
Comparasion Dendrite and Axon
Synapse
Peripheral Nerve
Investement
Nodus of ranvier
Sensory Nerve Receptor
Somesthetic Receptor
Free Nerve Endings
Encapsulated Sensory Nerve Endings
Krause’s end blub
Meissner’s Corpuscle
Panician Corpuscle
Ruffini Endings
Golgi tendon Organs
Muscle Spindle
-Motor Nerve Endings (Effectors)
Motor Unit
Motor End-Plate
Myelination
Reflect Arc
Ganglia
Craniospinal Ganglia
Autonomic Ganglia
-Nerve Degeneration and Regeneration
Peripheral Nervous System Response
Central Nervous System Response
-Autonomic Nervous System
Sympathetic Division
Parasympathetic Division













UNIT 3
CLOSING

3.1 Conclusion
1. It contains the majority of the nervous system and consists of the brain and the spinal cord.
2. The histological element of the central nervous system consists of :
a. Neuron
b. Glia
c. Nerve fiber
d. Accessory structures
3. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae. A typical cross section of the spinal cord is demarcated into an outer thick zone of white matter and an inner butterfly or H-shapped zone of gray matter.
4. Brain is subdivided into the large cerebrum, the much smaller cerebellum (meaning small brain), and inferiorly situated, funnel shaped brain stem.
5. Neuroglia include astrocytes (protoplasmic and fibrous), oligodendroglia, microglia and ependyma.
6. Bony encasement (the skull and vertebral column) protect the CNS from external trauma as well as by three membranous investments, the meninges. These fibrous coverings are the outermost, robust dura mater; the middle, spider web-like arachnoid; and the innermost, delicate, vascular pia mater.
7. Cerebrospinal fluid: ependymal cells, choroids plexuses, blood-brain barrier

3.2 Sugesstion
In the learning process of Histology materials especially Nervous System topic, there are many sub-topic that have to be undesrtood by students. So the students have to learning this topic not only from the books but also from the other media like internet, journal, magazine, etc.
In this paper, there are many mistakes. So the suggestion and critic will always be wished by writers.

REFERENCE


Bridgman, Telford.1995.Introduction to Functional Histology.Harper Collins College Publisher

Medical look . 2008.Spinal cord, (Online), (http://medical look /prev/index.html diakses 28 November 2009).


Wikipedia, anonym. 2009 . 2008. Nervous System , (Online), (http://google.co.id/prev/index.html diakses 28 November 2009).

Anonim, 1998 .grey and Whie matter , (Online), (http://mds/alsnewsmagazine prev/index.html diakses 2 November72009).

Nervous System

UNIT I
INTRODUCTION


1.1 Background
There are so many materials which have to be mastered by student in histology lesson, including Nervous System. In studying this material, student must learn deeply with the right concept. Many ways can use to support the learning process of this material, like make a paper. That is the reason why this paper is made. We make this paper not only to complete the assignment of Histology, but also to sharper our understanding of Nervous System material. In Nervous System divided into two part, there are Central Nervous System and Peripheral Nervous System. It contains the majority of the nervous system and consists of the brain and the spinal cord. In Peripheral Nervous System divided into Autonomic Nervous System and Somatic Nervous System . Together with the peripheral nervous system it has a fundamental role in the control of behavior. Because of the completable of these unit, So we must know and identify about apart of our self body that have many function in our body system. In this unit we just talk about Central Nervous System, because it is the main part of Nervous System that must known. The function of Central Nervous System is to receive and integrate incoming information (stimuli) corcening our internal and external environtment received from sensory receptors. Motor impuls are generated and discharged to effector organs (muscle and glands) for appropriate action, or the information may be stored as memory for future reference. Central Nervous System divided into Spinal cord and Brain. In each part have mainly function that very important in our body selves.

1.2 Problematic Formula
According to the background above, the problematic formula which appropriate are:
1. How is the histological structure of Central Nervous System?
2. How is the histological element of the Central Nervous System?
3. How is the histological structure of Spinal cord?
4. How is the histological structure of Brain?
5. How is the description of the Neuroglia?
6. How is the description of the Meninges?
7. How is the descriotion of the Cerebrospinal Fluid?

1.3 Purpose
According to the problematic formula above, the purpose of experiment are:
1. To Explain about histological structure of Central Nervous System.
2. To Explain about histological element of the Central Nervous System.
3. To Explain about histological structure of Spinal cord.
4. To Explain about histological structure of Brain.
5. To describe of the Neuroglia.
6. To describe of the Meninges.
7. To describe of the Cerebrospinal.


UNIT II
EXPLANATION

The nervous systems, together with the hormones secreted by endocrine system, maintain a balance among the various activities of the body, called homeostasis. It is the critical balance that prepares responses the body must make in response to external environmental stimuli. The nervous system is widespread throughout the body. Its interconnections are so extensive that nerve impulses can be transmitted along the network from one end to the other. Hence, an activity in one body region is likely to influence activity in other regions. Obviously, the functions can be very different, varying from a simple two neuron reflex to the complex special sense of hearing and seeing. (Telford, 1995)
The nervous system is derived from embryonic ectoderm through two rudiment, they are neural tube and the neural crest. The tube has its beginning at the neural plate which forms a thickened band of ectoderm along the midline of the embryo. The edge of the plate becomes depressed to form the neural tube. The anterior part of the tube enlarges to form the brain, whereas the smaller diameter posterior portion forms the spinal cord. (Telford, 1995)
The neural crest appears, just before the closure of the neural tube, as a cluster of specialized cells along the neural ridges. When the neural tube closes, the neural crest cells do not fuse with either the neural tube or the surface ectoderm, but remain between the structures. The principal derivatives of the neural crest are the spinal and cranial ganglia. (Telford, 1995)
The nervous system devided into two part, there are Central Nervous System and Peripheral Nervous System.

Central Nervous System
The central nervous system (CNS) is the part of the nervous system. In vertebrates, the central nervous system is enclosed in the meninges, connective tissue, and is protected by bone (skull and vertebral column). It contains the majority of the nervous system and consists of the brain and the spinal cord. Together with the peripheral nervous system it has a fundamental role in the control of behavior. The central nervous system is contained within the dorsal cavity, with the brain in the cranial cavity and the spinal cord in the spinal cavity. The brain is protected by the skull, while the spinal cord is protected by the vertebrae. (Wikipedia, 2009)
The function of central nervous system is to receive and integrate incoming information (stimuli) concerning our internal and external environment received from sensory receptors. Motor impulse are generated and discharged to effector organs (muscle and glands) for appropriate action, or the information may be stored as memory for future reference. (Telford, 1995)










Histological Structure of Central Nervous System
The histological element of the central nervous system consists of:
a. Neuron
Neuron is cell body, in the spinal cord located in a longitudinal, in the center of the cord it has H-shaped column, while in the brain, they are either in clusters (nuclei) deep in the brain or in layers (laminae) in the superficial cortex.
b. Glia
Glia is nonneunoral cells that are supportive or insulating elements throughout the central nervous system. The glial cells, derived from neuroectoderm, serve roles of connective tissue within the CNS tissue. Three types are found: (1) microglia, which represent macrophages of the CNS, (2) oligodendrocytes, which myelinate the axons within the CNS and, (3) astrocytes, which are a fibroblast-like supportive cell. These cells are characterized as fibrous astrocytes with unbranched processes and protoplasmic astrocytes with branched processes.
c. Nerve fiber
Nerve fiber is mostly long axons which may be myelinated or non-myelinated. They traverse and connect various regions of the brain and spinal cord. Most of the fiber is in definite bundles called tracts. These bundles are encapsulated in fibroconnective tissue in a manner similar to that seen in muscle tissue. Entire nerve bundles are surrounded by the epineurium (Nerve Bundle 1). Branching from the epineurium and dividing the nerve bundle into fascicles is the perineurium (Nerve Bundle 2). Finally each individual axon is surrounded by the endoneurium (Nerve Bundle 3).
d. Accessory structures
It is support and nourish the nervous elements are the investing meninges, abundant blood vessels, and the cerebral spinal fluid (CSF) in spaces, or reservoirs, called cisternae and ventricles.

-Central nervous system consists of the brain and spinal cord. The brain and spinal cord are each divided into gray and white matter.

a. Gray Matter
Grey matter is a major component of the central nervous system consisting of neuronal cell bodies, neuropil (dendrites and both unmyelinated axons and myelinated axons), glial cells (astroglia and oligodendrocytes) and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts. The color difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually has a grey-brown color which comes from capillary blood vessels and neuronal cell bodies.
Grey matter is distributed at the surface of the cerebral hemispheres (cerebral cortex) and of the cerebellum (cerebellar cortex), as well as in the depths of the cerebrum (thalamus, hypothalamus, subthalamus, basal ganglia - putamen, globus pallidus, nucleus accumbens, septal nuclei), cerebellar (deep cerebellar nuclei - dentate nucleus, globose nucleus, emboliform nucleus, fastigial nucleus), brainstem (substantia nigra, red nucleus, olivary nuclei, cranial nerve nuclei) and spinal grey matter (anterior horn, lateral horn, posterior horn).
The function of grey matter is to route sensory or motor stimulus to interneurons of the Central Nervous System in order to create a response to the stimulus through chemical synapse activity. Grey matter structures (cortex, deep nuclei) process information originating in the sensory organs or in other gray matter regions. This information is conveyed via specialized nerve cell extensions (long axons), which form the bulk of the cerebral, cerebellar, and spinal white matter. (Wikipedia. 2009)

b. White Matter
In white matter, parallel fascioles of myelinated axons dominate an exhibit a white, glistening appearance in the fresh condition. There are relatively few capillaris and very little extracelluler space. Because the function of white matter is largely conductive. It has considerably less metabolic activity. It differ greatly from gray matter by having no synapses no dendrites, and a limited blood supply.


-Spinal Cord
The Spinal Cord is connected to the brain and is about the diameter of a human finger. From the brain the spinal cord descends down the middle of the back and is surrounded and protected by the bony vertebral column. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae.
A typical cross section of the spinal cord is demarcated into an outer thick zone of white matter and an inner butterfly or H-shapped zone of gray matter. Near the center of the crossbar of the H is the small central canal lined with ependymal cells, a type of glia cell. On each side of the cord, the gray matter extends caudally and rostrally as two vertical columns called the dorsal (posterior) and ventral (anterior) horns. A small lateral horn is also seen in the thoracic and upper lumber regions.
There are three major types of the spinal gray matter, (1) the large, stelatte motor cells in the ventral horns, (2) the small and medium sized sympathetic efferent neurons in the lateral horns, and (3) the medium sized sensory neurons in the dorsal horns. All of these cells are confined to layers called laminae.
The white matter of the spinal cord consist of bundles of axons having spesific functions either motor of sensory, example pain, touch propioception. There are three of these large fibers columns or funiculi (L., cord), named their position example dorsal, ventral, lateral. Each faniculus is subdivided into smaller nerve bundles, the fasciculi, or tract. From the named of the tract, one can tell the location of the cells of origin and the termination of the fibers. For example, in the corticospinal tract, the cell bodies are in the cerebral cortex, and their axons end synaptically on neurons in the spinal cord.
While the pattern of gray and white matter is constant, their relative proportions vary at various levels. The greatest amount of gray matter is found in the cervical and lumbar enlargements of the cord because of the marked increase of neurons that are needed to serve the upper and lower limbs. The white matter increases in a caudal to rostral direction because the ascending pathways, connecting the spinal cord with the brain, are constantly recruiting fibers as they approach the brain. Furthermore, the axons of the descending tract gradually leave the tract to terminate in synapsea on the motor cells of the gray matter (ventral horn) of the cord. Recall that, in contrast to the gray matter, white matter contains only axons and glial cells.

-Brain
Brain is central nervous system. Brain located in cranium.The function of brain is manage most of movement, behavior and function of homeostatic like as pulse rate, blood pressure, and the other.
. Brain is subdivided into the large cerebrum, the much smaller cerebellum (meaning small brain), and inferiorly situated, funnel shaped brain stem. The latter is composed of nerve tract entering and leaving the brain as well as nuclei sub serving various reflect function

1. Cerebrum
The cerebrum is divided into two equal hemispheres by a deep, longitudinal fissure that contains the falx cerebri, a vertical extension of the dura meter. The cortex (gray matter) is highly convoluted, i.e., thrown into deep folds, which greatly increase its surface area. The convolutions are called gyri and the intervening depressions are sulci.
Histologically the cerebral cortex shows six ill defined layer or zone that vary In their cytoarchitecture from area to area of the brain. Three morphologically different cell types make up most of the neurons, i.e.,stellate or granular , fusiform, and phyramidal . By far the most conspicuous are the various sized phyramidal cells
All phyramidal cells have an apical dendrite that project toward the outer surface of the cortex. Its axon, emerging from the based of the phyramid, penetrates the deeper layers of the cortex eventually to form the efferent pathways of the brain in the white matter of the cortex








The Layer of Cerebral Cortex
The different cortical layers each contain a characteristic distribution of neuronal cell types and connections with other cortical and subcortical regions. One of the clearest examples of cortical layering is the stria of gennari in the primary visual cortex. This is a band of whiter tissue that can be observed with the naked eye in the fundus of the calcarine sulcus of the occipital lobe. The Stria of Gennari is composed of axons bringing visual information from the thalamus into layer four of visual cortex. The neurons of the cerebral cortex are grouped into six main layers, from outside (pial surface) to inside (white matter).
1. The molecular layer I, which contains few scattered neurons and consists mainly of extensions of apical dendritic tufts of pyramidal neurons and horizontally-oriented axons, as well as glial cell. Some Cajal-Retzius and spiny stellate neurons can be found here. Inputs to the apical tufts are thought to be crucial for the ‘‘feedback’’ interactions in the cerebral cortex involved in associative learning and attention. While it was once thought that the input to layer I came from the cortex itself, it is now realized that layer I across the cerebral cortex mantle receives substantial input from ‘‘matrix’’ or M-type thalamus cells (in contrast to ‘‘core’’ or C-type that go to layer IV
2. The external granular layer II, which contains small pyramidal neurons and numerous stellate neurons
3. The external pyramidal layer III, which contains predominantly small and medium-size pyramidal neurons, as well as non-pyramidal neurons with vertically-oriented intracortical axons; layers I through III are the main target of interhemispheric corticocortical afferents, and layer III is the principal source of corticocortical efferents
4. The internal granular layer IV, which contains different types of stellate and pyramidal neurons, and is the main target of thalamocortical afferents from thalamus type C neurons. as well as intra-hemispheric corticocortical afferents
5. The internal pyramidal layer V, which contains large pyramidal neurons (such as the Betz cells in the primary motor cortex); it is the principal source of subcortical efferents
6. The multiform layer VI, which contains few large pyramidal neurons and many small spindle-like pyramidal and multiform neurons; layer VI sends efferent fibers to the thalamus.establishing a very precise reciprocal interconnection between the cortex and the thalamus
It is important to note that the cortical layers are not simply stacked one over the other; there exist characteristic connections between different layers and neuronal types, which span all the thickness of the cortex. These cortical microcircuits are grouped into cortical columns and minicolumns, the latter of which have been proposed to be the basic functional units of cortex.]The functional properties of the cortex change abruptly between laterally adjacent points; however, they are continuous in the direction perpendicular to the surface. Later works have provided evidence of the presence of functionally distinct cortical columns in the visual cortex, auditory cortex and associative cortex.







Three drawings of cortical lamination each show a vertical cross-section, with the surface of the cortex at the top. Left: nissl- stained visual cortex of a human adult. Middle: Nissl-stained motor cortex of a human adult. Right: golgi stained cortex of a 1½ month old infant. The Nissl stain shows the cell bodies of neurons; the Golgi stain shows the dendrites and axons of a random subset of neurons

2. Cerebellum
The cerebellum is divided into right and left hemispheres, which are separated by a wormlike, segmented band of gray matter called vermis. The surface of the hemispheres is thrown into many thin, parallel folds or leaflets called folia. A thin cortex of gray matter covers the folia. Collections of neurons are buried in the underlying white matter, constituting the cerebellar nuclei.
A section through the cerebellar cortex reveals a trilaminar structure. It has outer molecular layer consisting of a few, small, basket type and stellate type neurons, myriad parallel fiber derived from granule cell and a massive dendritic arborization largely arising from the deeper purkinje cells. The intermediate layer is the purkinje layer, consisting of single layer of large purkinje cells whose cells bodies rest on the innermost granular layer. The purkinje cell has a large, prominent, flask-shaped cell body with a clear vesicular nucleus. Many nissl granules are scattered throughout the cytoplasm. Its most distinctive feature , however ,is its elaborate ,profusely branching, three like dendritic arbor ,which project into the molecular layer.
The innermost granular layer is the most conspicuous layer of the cerebellar cortex because it consists of large populations of closely packed, small granular cells whose nuclei essentially fill the cell. Under low power, the resemble lymphocytes.


3. Brain stem
The brain stem houses the main sensory and motor tract of the brain. They are collected and concentrated into this cylindrical mass of white matter, which tapper caudally to form the spinal cord. The cerebellum rest astride the central portion of the brain stem, called the spons. Other part are medulla oblongata located between the spinal cord and the spons, and the mid brain, situated rostral to the pons. The diencephalon extending rostrally from the mid brain.
Histological the brain stem exhibits a variety of neural structure . It is the funnel through which all the nerve pathways between the cerebrum and spinal cord must pass. Practically all of the tracts are composed of heavily myelinated fibers. It is in the brain stem that most of the cranial nerves arise or terminate. Therefore in the gray matter, where these event take place neuron are sequestered in clusters.

-Neuroglia
About 70-80% of all cells of the CNS are non-nervous; they’re mostly supportive cells, not neurons. Collectively they are called glial cells or neuroglia. As reinforcing cells, their function similar to connective tissue cells in other parts of the body. Neuroglia include astrocytes (protoplasmic and fibrous), oligodendroglia, microglia and ependyma.


a. Astrocytes
The largest of neuroglia, the star-shaped astrocytes (Gk., astron, star), are two types: protoplasmic or mossy and fibrous or spider-like. They are probably the same cell type, merely representing functional differences as reflected in their structural variation. Astrocytes are about 8-10 m in diameter.
Protoplasmic astrocytes are found chiefly in the gray matter. They have a rather large, round, light-staining nucleus surrounded by abundant granular cytoplasm. Many cytoplasmic processes terminate as expanded endings, called perivascular feet, which attach to the basal lamina of capillaries.
Fibrous astrocytes (spider cells) are found mainly in the white matter. As their name implies, they have long, thin, sparsely branching processes that extend considerable distances from the body. Otherwise they are similar to protoplasmic astrocytes.


b. Oligodendroglia
The oligodendrocyte, found in both white and gray matter, is the most common of the supporting elements of the CNS. It has a smaller cell body than astrocytes (measuring 6-8 m in diameter) and contains a small, often eccentric, dark nucleus with abundant heterochromatin. As its name implies, it has only a few (Gk., oligo, few) processes. It has considerably less cytoplasm and is more granular in appearance than the astrocytes. The oligodendrocytes do not have perivascular feet, yet their bodies may rest on capillaries. They are three types of oligodendrocytes; perivascular oligodendrocytes, perineural glia or satellite cells and interfascicular cells.



c. Microglia or Mesoglia
Microglia also called mesoglea because it derived from mesoderm. Microglia is the smallest of the glial cells with 5-7 μm in diameter. Their nuclei are small, irregular in shape and stain deeply. The cells have very limited, granular cytoplasm and only a few stubby, twisted processes. They make up about 4-5% of the total population of glial cells in the white matter but about 18% in the gray matter of the cerebral cortex. Their structural characteristics include the many dense inclusion bodies, lysosomes, and lipofuscin granules, which are suggestive of the cell’s phagocytic activity. The rER has long, attenuated cisternae, as contrasted to the short cisternae of oligodendrocytes.
Microglia is phagocytic cells, a part of the macrophage (reticuloendothelial) system. When engorged with cellular debris, principally degenerating myelin, they are called gittter cells. Their numbers greatly increase following the damage to the CNS. They may be brought to the site of injury by the general circulation or by migration from other areas of the CNS by amoeboid movement.










Source : www.mda/alsnewsmagazine.com
-Meninges
Bony encasement (the skull and vertebral column) protect the CNS from external trauma as well as by three membranous investments, the meninges. These fibrous coverings are the outermost, robust dura mater; the middle, spider web-like arachnoid; and the innermost, delicate, vascular pia mater. The three layers enclose the brain and spinal cord. They also sheathe the cranial nerves as they leave the cranium and the spinal nerves as they leave the vertebral canal.



Source: www.medical-look.com

a.Dura Mater
The cranial dura is a tough, relatively thick collagenous sheath consisting of two layers: (1) an outer, dense connective tissue, the endosteal layer, adheres to the inner surface of the bones of the skull. It is well supplied with blood vessels and nerves. (2) An inner meningeal layer consists of a thinner fibrous tissue membrane, which is covered on its inner surface by a single layer of flat, mesothelial cells. Thees two layers separate from each other to the certain locations to form the extensive venous (dural) sinuses.
The dura also sends out extensions that form partitions for the brain. The largest of these is the sickle-shaped falx cerebri, which extends along the superior longitudinal fissure and partially separates the left and right cerebral hemispheres. An extension of the dura as a thick septum between the cerebellar hemispheres is the falx cerebelli. Separating the cerebellum and cerebrum is another extension of the dura, the tentlike tentorium cerebelli. At its anterior aspect is an oval gap, the tentorial notch, which allows the brain stem to pass from the undersurface of the cerebrum into the posterior cranial fossa.
The spinal dura is a continuation of the inner layer of the cranial dura. From its attachment to the margins of the foramenmagnum of the skull, it descends as a closed tube to surround the spinal cord. It terminates as the coccygeal ligament that invests the filium terminale, the filamentous ending of the spinal cord.

a. Arachnoid
The arachnoid is a delicate, nonvascular membrane immediately beneath the dura. It has two components: (1) a thin, connective tissue component on contact with the dura and (2) a network of delicate trabeculae, which are covered with flat or low cuboidal epithelium. The trabeculae expand into the rather large space between the connective tissue and the underlying pia mater. This cavity is the important subarachnoid space, which is filled with CSF.
In some areas adjacent to the venous dural sinuses, the arachnoid perforates the dura mater to open into the venous sinuses. These protrusions, carrying a central core of trabeculae, are the arachnoid villi, which function to transfer the CSF back into the blood stream.

b. Pia Mater
The pia mater is a thin, highly vascular sheath that adheres closely to the brain and spinal cord. It follows all of their surface irregularities. Therefore, unlike the dura and arachnoid, the pia closely covers the convolutions (gyri) of the brain and extends into the depths of the sulci. As blood vessels penetrate the brain and spinal cord they carry the pia with them for a short distance, creating a perivascular space.
The pia mater consists of two poorly defined layers. The inner, thinner layer of reticular and elastic fibers is firmly attached to the underlying nervous tissue. The more superficial layer receives fibrous attachments (trabeculae) from the arachnoid. Its external surface is a single layer of squamous cells of mesodermal origin. This cellular covering is continuous with cells covering the arachnoid. Because both the pia and the arachnoid are so closely related, they are often described as a single structure, the pia-arachnoid membrane, or leptomeninx.
-Cerebrospinal Fluid
Most of the CSF is produced in choroids plexuses in the ventricles of the brain. The remainder of the fluid, perhaps as much as 40%, is formed at other sites, e.g., at the blood vessels, and the ependymal lining cells of the ventricles and spinal canal.
a. Ependymal Cells
In embryonic development, the brain and spinal cord develop as a hollow tube. Lining this neural tube are primitive neuroopithelial cells that later persist as cuboidal ependymal cells, a type of neuroglia. They line the four ventricles of the brain and the central of the spinal cord and cover the coroid plexuses.
Many of these cells have an abundance of microvilli and one or two cilia on their luminal surface. The presence of cilia is not unexpected because all the cells had cilia during some stage in their development. The basal end of these ependymal lining cell do not rest on a basement membrane, instead, the base is tapered to form a single, branched process that extends into the underlying nervous tissue, in thin region of the brain, some of these processes may extend to the external surface of the brain. Along with other glial cell processes, they contribute to the formation of the glia limitans.
Transmission electron micograph of the lining ependymal cells reveal large accumulations of mitochondria in the apices of the cells. The other cell organelles are similar to the astrocyte, e.g., limited rER and ribosome, small Golgi complexes, and many bundles of neurofilaments; each filament is about 6-10 mm in diameter.
In certain region of the ventricles of the brain, the lining ependymal cells cover tufts of capillaries, called choroids plexuses. This special layer of ependyma is the choroids plexus epithelium, which is involved in the production of the CSF.

b.Choroids plexuses
The choroids plexuses are delicate capillary network formed by invaginations of the pia mater called thela chorioidea. As the plexuses invaginate into the ventricles, they are convered by a layer of cuboidal epithelium, the ependymal cells that line the ventricles (brain cavities). This epithelium shows evidence of high metabolic activity, involving the expenditure of energy in the production of CSF. Such cytological characteristic of the epithelium include numerous mitochondria; abundance cytoplasm; and large, clear, vesicular nucleus. Also, the plasma membrane of the free surface of these cells has irregular microvilli, suggesting an absorptive function.
Eventually, the CSF leaves the interior of the brain by way of three foramina to enter the subarachnoid space surrounding the brain. The fluid then flow down the subarachnoid space surrounding the spinal cord. Thus, the CSF serves as an effective fluid buffer or cushion for the CNS, protecting it against sudden movements of the head and body.
As the fluid diffuses over the brain, it escapes from the subarachnoid spce by passing through villi that perforate the dura into the dural venous sinuses of the brain. The arachnoid villi became hyperthrophied with age and are then called Pacchionian bodies or arachnoid granulations. They may be of sufficient size to produce a pitting of the cranial bones, which can be seen in the dried skull.
c. Blood-Brain Barrier
When certain drugs, pigments, or dyes are administered intravenously to animals, these substances do not enter the tissues of the brain or spinal cord, yet they penetrate most other tissues of the body. Such absorptions suggest the presence of barrier between the capillaries of the CNS and the surrounding nervous tissue, i.e., a blood-brain barrier.
It was not until EM studies were available, however, that the elements of the barrier were identified. They include the presence of (1) many tight junctions between adjacent endothelial cells that line the continuous-type capillaries of the CNS, (2) a well developed basal lamina surrounding these capillaries, and (3) the extensive covering of the external surface of the capillaries by myriad end-feet process from atrocytes. Such a physiohistologic barrier normally allows only O2, CO2, and small nutrient molecules to pass, which sustain the easily damaged neurons and delicate glial cells.

COMPARISON OF LAYERS IN CENTRAL NERVOUS SYSTEM
LAYER NUMBER NAME NERVE CELL BODIES PROCESSES AND SYNAPSES
Cerebrum
I
Molecular or Plexiform
Only few cells, mostly horizontal cells (of Cajal) and a few Golgy type II cells
Terminal dendrites of fusiform and pyramidal cells from deeper layers, also axonalsynapses with neuron possessing ascending axons, i.e.,Martinotti cells
II Outer Granular Many small pyramidal and stellate cells, which appear as granules, called small granulle cells Dendrites of both cell types terminate here, whiletheir axon descend to deeper layers; axons of deep Martinotti cells synapse here
III Outer Pyramidal Most cels are medium-sized pyramidal cells; others are large pyramidal and Martinotti cells Apicaldendrites extend into molecular layer;axons descend to synapse in deeper layers
IV Inner Granular Chiefly small, stellate cells that resemble granules under low magnification Axons of smaller cells largely remain in layer;axons of larger cells descend to synapse in deeper layers
V Inner Pyramidal or Ganglionic Principally large and medium-size pyramidal cells, in motor cortex giant cells of Betz are prominent Axons pass into white matter,while apical dendrites ascend intomolecular layer or may arborize within layer
VI Fusiform and multiform Fusiform (spindle) cells dominate; their long axes are perpendicular to cortical surface Apical dendritesof smaller spindlecells arborizewhitin layer, other ascend into upper layers; allaxons of spindle cells enter white matter;axons from cells of other layers synapse here
Cerebellum
I
Molecular
(outer)
Few small basket and stellate cells
Theirdendrites arborize in layer, extensive Purkinje cell dendritic ramifications dominate area; T-shaped axons of granule cells synapse here
II Purkinje
(middle) Single row of large, flask-shaped Purkinje cells associated with afew small, basket cells and Golgi type II cells Massive, treelike dendrites extend into molecular layer; Purkinje axons extend trough the inner granular layer to enter whitematter
III Granular
(inner) Numerous,closely packed dark-staining, small granule cells, some GolgitypeII cells inupper partr of layer Thin, unmyelinated axons of granulecells ascend into molecular layer,their short dendrites terminatein glomeruli near cells bodies;dendritesog golgi cells terminatein molecular layer
Spinal Cord
I

White matter
Virtually none
Parallelbundles of myelinated axons fill field; essentially no dendrites or synapses present
II Gray matter Three types of moltipolar neurons: (a) Large,stellate motor cells in ventral horn; (b) small,stellate, internuncial cells between ventraland dorsal horns;(c) medium-sized stellate sensory cellsin dorsal horns Abundance of fine unmyelinated axons; frequent axonic synaptic terminal; extensive dendritic plexuses surround nerve cells bodies

Peripheral Nervous System
Afferen and efferent fiber
-The Neuron Doctrine
-The Neuron
Morpholigal Classification
Perikaryon
Cell Processes
Axon
Dendrites
Comparasion Dendrite and Axon
Synapse
Peripheral Nerve
Investement
Nodus of ranvier
Sensory Nerve Receptor
Somesthetic Receptor
Free Nerve Endings
Encapsulated Sensory Nerve Endings
Krause’s end blub
Meissner’s Corpuscle
Panician Corpuscle
Ruffini Endings
Golgi tendon Organs
Muscle Spindle
-Motor Nerve Endings (Effectors)
Motor Unit
Motor End-Plate
Myelination
Reflect Arc
Ganglia
Craniospinal Ganglia
Autonomic Ganglia
-Nerve Degeneration and Regeneration
Peripheral Nervous System Response
Central Nervous System Response
-Autonomic Nervous System
Sympathetic Division
Parasympathetic Division













UNIT 3
CLOSING

3.1 Conclusion
1. It contains the majority of the nervous system and consists of the brain and the spinal cord.
2. The histological element of the central nervous system consists of :
a. Neuron
b. Glia
c. Nerve fiber
d. Accessory structures
3. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae. A typical cross section of the spinal cord is demarcated into an outer thick zone of white matter and an inner butterfly or H-shapped zone of gray matter.
4. Brain is subdivided into the large cerebrum, the much smaller cerebellum (meaning small brain), and inferiorly situated, funnel shaped brain stem.
5. Neuroglia include astrocytes (protoplasmic and fibrous), oligodendroglia, microglia and ependyma.
6. Bony encasement (the skull and vertebral column) protect the CNS from external trauma as well as by three membranous investments, the meninges. These fibrous coverings are the outermost, robust dura mater; the middle, spider web-like arachnoid; and the innermost, delicate, vascular pia mater.
7. Cerebrospinal fluid: ependymal cells, choroids plexuses, blood-brain barrier

3.2 Sugesstion
In the learning process of Histology materials especially Nervous System topic, there are many sub-topic that have to be undesrtood by students. So the students have to learning this topic not only from the books but also from the other media like internet, journal, magazine, etc.
In this paper, there are many mistakes. So the suggestion and critic will always be wished by writers.

REFERENCE


Bridgman, Telford.1995.Introduction to Functional Histology.Harper Collins College Publisher

Medical look . 2008.Spinal cord, (Online), (http://medical look /prev/index.html diakses 28 November 2009).


Wikipedia, anonym. 2009 . 2008. Nervous System , (Online), (http://google.co.id/prev/index.html diakses 28 November 2009).

Anonim, 1998 .grey and Whie matter , (Online), (http://mds/alsnewsmagazine prev/index.html diakses 2 November72009).