The Theory of Plate Tectonics

The theory of plate tectonics (English : Plate Tectonics ) is a theory in the field of geology developed to explain the evidence of large -scale movements performed by the lithosphere of the earth . This theory has also replaced the cover and continental shift theory is first put forward in the first half of the 20th century and the concept of seafloor spreading were developed in the 1960s .
Outermost part of the Earth's interior is made up of two layers . At the top there is the lithosphere consists of the crust and the upper part of the mantle is rigid and solid . Beneath the layers of the lithosphere asthenosphere are solid but can flow like a liquid with a very slow and in the geological time scale is very long due to the viscosity and shear strength (shear strength ) is low . Deeper , part of the mantle below the asthenosphere is more rigid nature become again . The cause is not the cooler temperatures , but high pressure .
Layers of lithosphere is divided into tectonic plates ( tectonic plates ) . On Earth , there are seven major plates and many plates smaller . The lithospheric plates ride on top of the asthenosphere . They are moving relative to each other in the plate boundaries , either divergent ( away ) , convergent ( colliding ) , or transform ( sideways ) . Earthquakes, volcanic activity , mountain-building , and oceanic trench formation generally occurs in areas all along the plate boundaries . The lateral movement of the plates is typically 50-100 mm speed / a. [ 1 ]

The development of theoryMaps with details that indicate tectonic plates and the direction of its motion vector
At the end of the 19th century and early 20th century , geologists assumed that the appearance of major earth - based permanent appearance . Most geological appearance as mountains can be explained by vertical crustal movement as described in the theory geosinklin . Since 1596 , it has been observed that the Atlantic Ocean coast of the face-off between the continents of Africa and Europe with North America and South America have similar shapes and seem to never become one . This accuracy will be more obvious if we look at the edges of the continental shelf there . [ 2 ] Since then many theories have been advanced to explain this , but everything is at a stalemate due to the assumption that the earth is completely solid complicate the discovery of appropriate explanations . [ 3 ]
The discovery of radium and its heating properties in 1896 to encourage the review of the age of the earth , [ 4 ] having previously obtained estimates of the rate of cooling and assuming the Earth's surface radiated like a black body . [ 5 ] From these calculations it can be concluded that even if at first the earth is an object that is red - flare , the Earth's temperature to drop to as it is now in a few tens of million years . With the heat source of this newfound scientists consider it absurd that the Earth is actually much older , and its core is still hot enough to be in a liquid state .
The theory of plate tectonics shift hypothesis comes from the Continent ( continental drift ) Alfred Wegener proposed in 1912. [ 6 ] and developed further in his book The Origin of Continents and Oceans , published in 1915 . He suggested that the continents are now there once was a face that moves away landscapes thus releasing the continents from the Earth 's core as ' iceberg ' of a low type of granite that mass floating on a sea of ​​denser basalt . [ 7 ] [ 8 ] However , in the absence of detailed evidence and calculation of the forces involved , this theory marginalized . Maybe Earth has a solid crust and a liquid core , but it still seems unlikely that the parts of the crust could move . Later, the theory proposed dibuktikanlah British geologist Arthur Holmes in 1920 that link parts of the crust under the ocean possibilities . Also proved his theory that convection currents in the Earth's mantle is the driving force . [ 3 ] [ 9 ] [ 10 ]
The first evidence that the plates did have movement obtained from the discovery of differences in the magnetic field direction in rocks of different age . This discovery was first revealed at a symposium in Tasmania in 1956. At first , the invention is incorporated into the theory of earth expansion , [ 11 ] but more precisely later lead to the development of plate tectonic theory which explains the expansion ( spreading ) as a consequence of vertical movement ( upwelling ) rocks , but avoids the necessity of the earth continues to grow in size or expansion ( expanding earth ) by entering the subduction zone / hunjaman ( subduction zone) , and cesarean translation ( translation fault ) . At that time the theory of plate tectonics changed from a radical theory becomes a theory commonly used and later widely accepted among scientists . Further research on the relationship between seafloor spreading and the Earth's magnetic field reversal ( geomagnetic reversal ) by geologist Harry Hammond Hess and Ron G. Mason oseanograf [ 12 ] [ 13 ] [ 14 ] [ 15 ] shows the exact mechanisms that explain the vertical movement of rock The new .
Along with the receipt of the Earth's magnetic anomaly indicated by parallel rows of symmetrical with similar magnetization on the seafloor on either side of the mid -oceanic ridge , plate tectonics became widely accepted . Rapid advances in seismic imaging techniques initially in and around Wadati - Benioff zones and a variety of other geological observation was soon confirmed as the theory of plate tectonics that have exceptional ability in terms of explanation and prediction .
Research on the deep ocean floor , a branch of the rapidly growing marine geology in the 1960s played an important role in the development of this theory . Correspondingly, plate tectonic theory was developed in the late 1960s and has been fairly universally accepted in all disciplines , as well as renew the world of earth sciences by providing an explanation for a wide range of geological phenomena and their implications in other fields such as paleogeography and paleobiology .Key Principles
Part of the outer layer , the interior of the Earth is divided into layers of the lithosphere and the asthenosphere layer based on differences in mechanical and heat transfer of the occurrence . Llitosfer more cold and rigid , while the asthenosphere is hotter and mechanically weaker . In addition , the lithosphere loses heat by conduction , whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient . This division is very different from the chemical division of the earth into a core , mantle , and crust . Lithosphere includes the crust and also own a portion of the mantle .
A portion of the mantle may be part of the lithosphere or the asthenosphere at different times , depending on the temperature , pressure , and shear strength . Key principle of plate tectonics is that the lithosphere separated into tectonic plates different . This slab moves over the asthenosphere ride that has so behave like viscoelastic fluid . The movement of the slab could reach 10-40 mm / a ( fast as fingernails grow ) as in the Mid-Atlantic Ridge , or can reach 160 mm / a ( fast hair growth ) as the Nazca Plate . [ 16 ] [ 17 ]
These plates about 100 km thick and consist of lithospheric mantle on which is coated with a stretch of one of two types of crustal material .The first is the oceanic crust or often called the " sima " , a combination of silicon and magnesium .The second is the continental crust that is often called " bad luck " , a combination of silicon and aluminum .
The two types of crust differ in terms of thickness where the continental crust has a thickness that is much higher than the oceanic crust . The thickness of the continental crust reaches 30-50 km while the oceanic crust is only 5-10 km .
Two plates will meet along the plate boundaries ( plate boundary) , which is an area where geological activity such as earthquakes generally occur and the formation of topographical appearance such as mountains, volcanoes and oceanic trenches . Most active volcano in the world is above the plate boundaries , such as the Pacific Ring of Fire ( Pacific Ring of Fire ) in the Pacific Plate 's most active and widely known .
Plate tectonics may be continental or oceanic crust , but usually one plate consists of both. For example , the African Plate includes the continent itself and the base portion of the Atlantic Ocean and the Indian .
The difference between the continental crust by oceanic crust is based on the density of the constituent material .

    Oceanic crust is denser than continental crust due to differences in the comparison of the various elements , especially silicon .

    Continental crust is denser because the composition contains less silicon and more heavier material . In this case , the oceanic crust is said to be more mafic than felsik . [ 18 ] Thus , oceanic crust generally lies below sea level as most of the Pacific Plate , while the continental crust is raised to above sea level , following a principle known as isostacy .
Types of Plate BoundariesThree types of plate boundaries ( plate boundary) .
There are three types of plate boundaries are different from the way the plates move relative to one another . These three types are each associated with different phenomena on the surface . Three types of plate boundaries are:

    Limit transform ( transform boundaries ) occur when plates move and experiencing friction with each other laterally along the transform fault ( transform fault ) . The second plate relative motion can be sinistral ( left on the side opposite to the observer ) or dekstral ( to the right on the opposite side of the observer ) . Examples of this type of fault is the San Andreas Fault in California .
    Limit divergent / constructive ( divergent / constructive boundaries ) occurs when two plates move away from each other . Mid -oceanic ridge and fracture zones ( rifting ) enabled is an example of a divergent boundary
    Limit convergent / destructive ( convergent / destructive boundaries ) occurs when two plates rub against each other approached to form a subduction zone when one plate moves under another , or a continental collision ( continental collision ) if the two plates contain continental crust . Deep ocean trenches usually located at a subduction zone , where the pieces of plate that has taken root contains many are hydrates ( containing water ) , so that the water content is removed when the heating occurs mixed with the mantle and lead to melting , causing volcanic activity . An example of this can be seen in the Andes Mountains in South America and the Japanese island arc ( Japanese island arc ) .
Strength Activator Plate Movement
The movement of the tectonic plates could occur due to the relative density of oceanic lithosphere and the asthenosphere is relatively weak character . The release of heat from the mantle has been found to be the original source of energy that drives plate tectonics . The views were approved today , although still quite debatable , is that excess density of the oceanic lithosphere makes infiltrate downward at subduction zones is the strongest source of slab movement .
At the time of its formation in the mid- ocean ridge , oceanic lithosphere initially has a lower density than the surrounding asthenosphere , but the density increases with aging due to the cooling and thickening . The magnitude of the density of old lithosphere relative to the underlying asthenosphere allows the intrusion into the mantle at subduction zones so that the source of most of the driving force - plate movement . The weakness of the asthenosphere allows the plates to move easily towards a subduction zone [ 19 ] Although subduction is believed to be the strongest force driving plate - movement , there is another driving force plate as evidenced by the North American plate , the Eurasian plate is also moving but did not experience subduction anywhere . Driving source is still a topic of intensive research and discussion among scientists in earth science .
Two and three -dimensional imaging of the Earth's interior ( seismic tomography ) shows heterogeneous density distribution throughout the mantle laterally . Variations in the density could be material ( from rock chemistry ) , mineral ( from variations in mineral structures ) , or thermal ( through thermal expansion and contraction from heat energy ) . Manifestations of heterogeneity in the lateral density is mantle convection from buoyancy ( buoyancy forces ) [ 20 ] How mantle convection relates directly and not by the movement of the planet into a field that is still being studied and dealt in geodynamics . With one way or another , this energy must be transferred to the lithosphere that the tectonic plates to move . There are two main types of styles in its influence to the movement of the planets , ie friction and gravity .Stringed style
basal drag
    Large-scale convection currents in the upper mantle asthenosphere distributed through , so that the movement is driven by friction between the asthenosphere and lithosphere .slab suction
    Provide local convection currents pull down on the plates in subduction zones at ocean trenches . Penyerotan slab ( slab suction ) can occur in conditions where traction geodinamik basal plates continue to work on this at the time he entered into the mantle , although actually pull more work on both sides of the plate , top and bottom
gravitation

    Debris gravity : plate movement occurs due to higher in oceanic ridge plate . Cold oceanic lithosphere becomes denser than the hot mantle is the source , then by increasing the thickness of the plate sinks into the mantle to compensate for weight, produces little lateral inclination proportional to the distance from the axis . : In geology texts on basic education , this process is often referred to as a doronga . However , the actual title is more appropriate because of the topography of a plate debris can be very different and dike topography ( ridge ) that performs the division is simply the most dominant feature . For example , swelling of the lithosphere before it fell to the bottom of the plate adjacent produce can affect the appearance of the topography . Then , press the side of the mantle plume under the tectonic plates can also change the topography of the ocean floor .Slab - pull (tension slab )
    Plate movement partly caused also by the weight of cold, dense plates descend into the mantle in the oceanic trenches . [ 21 ] There is considerable evidence that convection also occurs in the mantle with a large enough scale . Upward movement of the material in the mid -oceanic ridge is likely part of this convection . Some early models of plate tectonics suggests that these plates riding on top of the cells like conveyor belts .
    However , most scientists now believe that the asthenosphere is not strong enough to directly cause movement by the friction forces . Slab pull themselves very likely to be the largest force acting on the plate . Newer models also provide an important role in penyerotan ( suction ) in the trough , but the slab as the North American Plate subduction not experience anywhere else , but also to have movement as well as the African Plate , Eurasian , and Antarctic . The main driving force for the movement of the slab and the energy source itself is still a matter of ongoing research
Outside force
In a study published in the January-February issue of 2006 of the bulletin of the Geological Society of America Bulletin , a team of scientists from Italy and the United States argued that the plate component that leads to the west comes from the Earth 's rotation and tidal friction months that followed . They said because the Earth spins eastward beneath the moon, the moon's gravitational pull is very small even though the Earth's surface layer back westward .
Some people also put forward controversial idea that these results may also explain why Venus and Mars does not have plate tectonics , ie in the absence of Venus and the moon in the small size of the moons of Mars to give effect to such tides on earth . [ 22 ]
This thought itself is actually not new . This in itself originally put forward by his own father of this hypothesis , Alfred Wegener , and then challenged physicist Harold Jeffreys who calculated that the magnitude of the frictional forces required oasang will quickly bring the Earth's rotation to stop since a long time .
Many plates are moving north and west , even many basic movement to the west is the Pacific Ocean from the point of view of the center of expansion ( spreading ) in the Pacific Ocean that leads to the east . It also said that relative to the lower mantle , there are fewer components that leads to the west on the movement of all platesThe relative significance of each mechanismPlate movement , based on NASA JPL GPS satellite data . Vector here indicate the direction and magnitude of movement .
Vectors are actually on the movement of a planet should be a function of all the forces acting on the plate . However , the problem is how much each process to take part in the movement of each plate Diversity geodinamik conditions and properties of each plate should make a difference in how these processes are actively moving the plate . one way to overcome this problem is by looking at the rate at which each plate is moving and to consider the available evidence for each of the driving forces of plate as far as possible .
One of the most important relationships found is that lithospheric plates are sticky on the tersubduksi plates move much faster than plates that do not . For example , the Pacific Plate subduction zone surrounded ( Ring of Fire ) that move much faster than plates in the Atlantic are sticky on the adjacent continent and not a plate tersubduksi . Thus , the force berhubungkan with downward moving plate ( slab pull and slab suction ) are the driving force that determines the movement of the plates except for the plates were not disubduksikan . Although however, the driving force of plate movement itself is still a matter of debate and research scientistsMain platesMap of tectonic plates
Major tectonic plates namely :

    African Plate , covering Africa - Continental plate
    Antarctic Plate , covering Antarctica - the continent Plate
    Australian Plate , covering Australia ( fused with Indian Plate between 50 to 55 million years ago ) - Continental plate
    Eurasian plate , covering Asia and Europe - Continental plate
    North American Plate , covering North America and northeastern Siberia - Continental plate
    South American Plate , covering South America - the continental plate
    Pacific Plate , covering the Pacific Ocean - the ocean plate
Another important plates smaller include the Indian Plate , Plate Arabia , the Caribbean Plate , the Juan de Fuca Plate , Cocos Plate , Nazca Plate , Philippine Plate , and the Scotia Plate .
The movement of plates has caused the formation and breakdown of continents over time , including the formation of the supercontinent that includes most or all of the continents . Supercontinent Rodinia formed at roughly 1 billion years ago and covers most or all of Earth's continents , and broken up into eight continents around 600 million years ago . The eight continents later reorganized into another supercontinent called Pangaea , which also split into Laurasia ( which became North America and Eurasia ) and Gondwana ( which became the remaining continents )

Baca selengkapnya »

Menahan Perasaan...

Menahan Perasaan. Sulit.

Menahan perasaan itu gak mudah. Kita sudah berlatih menahan diri,  setahun sekali selama 30 hari, walau mungkin tidak sempurna, menahan lapar, dahaga, amarah. Tapi bagi aku menahan perasaan….. !!

Bukan menahan perasaannya yang menjadi masalah,  tp komplikasinya dalam keseharian. Apa yang terjadi? seperti orang pesakitan, bedanya fisiklah yang bebas tapi hati dan pikiran yang terbelenggu. Produktifitas menurun, plus berat badan menurun (darn, i’m screwed). Sholat memang memberi ketenangan namun entah kenapa masih tidak cukup :( I have never felt anything like this before.

kesibukan memang pelarian dan sahabat adalah obat untuk melupakan, tapi dalam kesendirian dan kesunyian…. gagal saya menjadi kuat. Kepala menjadi berat, penuh dengan bayang-bayang semu. Perlukan air mata keluar? is it worth?

I am a girl, with the logic above my emotion.

I am a girl, with the obstinacy of the plume.

I am a girl, with the toughness to survive

but  I am a girl  who also only an ordinary human.

Perasaan cinta yang masih menyelimuti hati, lama-lama akan menghujam kuat dan menjadi karat hati yang amat sulit dibersihkan. Bahkan dokter sekalipun kebanyakan angkat tangan untuk menyembuhkan penyakit kasmaran. Uhuk. Jatuh Cinta akan membuat aku jatuh ke dalam cinta yang tidak berkah, terupurk di dalamnya, terhina karenanya, membuat aku benar-benar jatuh. Membuat aku enggan bangkit dari tempat tidur karena menikmati khayalan indahnya bisa bersama dirinya, membuat kita menangis sia-sia karena merasa kehilangan dia. Menahan perasaan cinta lebih baik daripada mengunkapkannya, mengungkapkan perasaan cinta ibaratnya sebuah pemantik api yang akan membakar api asmara yang sulit untuk dipadamkan. Astagfirullah.....

Aku membayangkan perasaan aku bebas, pikiran yang ringan dan kepak sayap imajinasi yang melayang tinggi ke angkasa. (jadi pengen ke pantai! karena di sana aku bisa melihat tempat yang luas, horizon langit yang seolah membuat saya berada dalam ruang tanpa batas, pengen ke gunung, karena di sana aku merasa berdiri di atas dunia).

Aku ingin berhenti, tapi tidak sanggup.

Aku ingin menutup hati, tapi itu artinya menyalahi anugrah kodrati.

Untuk seseorang yang membuat hati aku porak poranda.

Baca selengkapnya »

Perasaan vs Logika

Seperti membawa sebuah anak panah dan membidik ke arah sasaran yang tepat.
Dan itu bukanlah suatu hal yang mudah. Ketika jatuh cinta dan rasa sayang adalah suatu hal yang susah untuk diarahkan.

Cinta memang tidak dapat diatur jatuhnya kepada siapa tapi:

“ Orang yang tidak dapat memanah dengan arah yang benar tentu hasil sasarannya juga tidak tepat, yang dampaknya juga kurang baik untuk dijalankan meskipun bisa membuat bahagia” (hihihi…saya mengutip kata-kata bagus ini dari pacar saya)

Ya, bahagia dalam artian SEKETIKA dan SEMENTARA.
Mengapa Tuhan menciptakan manusia dengan menggunakan LOGIKA dan PERASAAN.

Sisi positif:

Ketika anda menggunakan LOGIKA anda bisa memutuskan sesuatu dengan cara yang benar, membela yang benar, memilih yang baik demi sebuah kebaikan, bijaksana dan adil..yang tentunya membawa kebahagiaan anda dan orang lain dalam jangka panjang.
Namun ketika PERASAAN anda ditumbuhkan, gunakanlah dengan sebaik-baiknya, untuk menolong sesama, membangun religi, melindungi dan membantu yang lemah terhadap sesama. Dalam hal ini tentu hati nurani anda akan terbangun, menjauhkan anda dari rasa BENGIS dan KEJAM.

Sisi negatif:

Ketika terlalu menggunakan LOGIKA anda secara berlebihan, egois, hati nurani anda akan tertutup, tidak percaya akan adanya TUHAN, melanggar moral, dan tidak ada rasa Iba dan Kasihan terhadap sesama.
Ketika anda juga terlalu menggunakan PERASAAN anda tidak dapat memutuskan dan memilih secara objektif, mana yang benar dan mana yang salah. Keputusan hanya didasarkan LIKE or DISLIKE.
Gunakanlah LOGIKA dan PERASAAN secara seimbang. Kapan anda harus memakai PERASAAN dan kapan anda harus memakai LOGIKA.
Ketika anda memutuskan sesuatu dengan menggunakan PERASAAN tumbuhkan LOGIKA anda untuk dapat memilih dan memutuskan secara baik dan adil?
Ketika anda memutuskan sesuatu dengan menggunakan LOGIKA tumbuhkan PERASAAN anda apakah perbuatan anda bermoral???? Atau menyalahi aturan etika sosial??

Ketika anda merasa DILEMA, pikirkan JANGKA PANJANG dan hitunglah mana yang lebih banyak berdampak buruk dan mana yang lebih banyak berdampak baik dalam kehidupan jangka panjang anda. Saya yakin dengan diri saya, apabila memikirkannya akan membawa kebaikan dalam hidup saya di waktu yang akan datang atas apa yang saya korbankan di waktu sekarang.

Itulah gunanya mengapa Tuhan menciptakan manusia dengan PERASAAN dan LOGIKA, keduanya saling mempengaruhi dan mengatur jalan keputusan hidup anda, bahkan tanggung jawab anda kepada Tuhan.
Yang dapat mengendalikan PERASAAN anda adalah LOGIKA, dan yang dapat mengendalikan LOGIKA anda adalah PERASAAN.

PERASAAN adalah NAFSU.

Saya lebih memilih LOGIKA untuk mengendalikan PERASAAN saya,
karena saya bukan BINATANG.
Ketimbang saya memilih PERASAAN tetapi munumpulkan LOGIKA.
kalau sperti itu hiduplah seperti BINATANG.
Dan anda akan hidup menjadi ORANG LEMAH.

Saya pernah merasa bingung. Untuk melakukannya memang bukan hal yang mudah. Tetapi, bila anda melakukan sesuatu dan memutuskan dengan BENAR, anda akan hidup dalam jalur yang BENAR dan mendapatkan ganti atas PENGORBANAN anda dengan KEBAIKAN di waktu yang akan datang.

Dalam tanda kutip saya tidak mencari KESEMPURNAAN dengan LOGIKA saya, tapi saya mencari jalan KEBENARAN atas apa yang saya pilih, niscaya KEBAHAGIAAN itu akan terbangun dari jalan KEBENARAN yang saya pilih.

Silahkan anda pilih sakit tapi nanti bahagia?

Atau bahagia tapi nanti sakit?

Saya lebih baik memilih ”SAKIT” tapi nanti ”BAHAGIA”.

Contoh keberhasilan memakai teori ini adalah orang tua saya yang begitu banyak mengorbankan perasaan, cinta, kesenangan sendiri, ego dan banyak hal di masa mudanya untuk kebahagiaan di waktu yang akan datang. Selamat mencoba bagi anda-anda yang sedang BIMBANG. Smoga KEBENARAN ada di pihak anda. =)

Baca selengkapnya »

Brain of Human

Brain (English : encephalon ) is a central nervous system ( CNS ) in vertebrates and many other invertebrates .
The human brain [ 1 ] is a central structure that has a volume setting around 1.350cc and consists of 100 million nerve cells or neurons . Brain organize and coordinated in large part, movement , behavior and homeostatic body functions such as heart rate , blood pressure , body fluid balance and body temperature . The human brain is responsible for setting the whole body and human thought . Therefore there is a strong link between the brain and thinking . Nerve cells inside the brain and is believed to affect human cognition . Knowledge of the brain affects the development of cognitive psychology . The brain is also responsible for functions such as recognition , emotion . memory, motor learning and all other forms of learning .
The brain is made up of two types of cells : neurons and glia . Glia serve to support and protect the neurons , whereas neurons carry information in the form of electrical pulses known as action potentials . They communicate with other neurons and throughout the body by sending a wide variety of chemicals called neurotransmitters . These neurotransmitters are sent on a gap known as a synapse . Invertebrates such as insects may have millions of neurons in the brain , large vertebrates can have up to a hundred billion neurons .
Neurons of the brain contains two types of fatty acids PUFA (English : polyunsaturated fatty acids ) , arachidonic acid ( AA ) and docosahexaenoic acid ( DHA ) which is located in the SN2 position of phosphoglycerides molecules in the cell membrane of neurons . [ 2 ] PUFAs regardless of phosphoglycerides by stimulation of phospholipase PLA - 2 . AA molecules released will be processed by the enzyme cyclo oxygenase into prostaglandins and tromboksana , or processed by the enzyme 5 - lipo oxygenase be lipoksin . Both AA and DHA can be processed by lipo oxygenase enzyme to form hydroxy derivatives and leukotriena .Parts of the human brain
In the vertebrate brain anatomy , brain is the front upper part of the brain . At this stage of development of the central nervous system , the developing forebrain and separated into a large brain and diencephalon . If in the embryo , the forebrain obstacles to develop into both lobes of this , there will be a condition called holoprosensefali (English : holoprosencephaly ) .cerebrum
Big brain is the most prominent part of the front of the forebrain . The brain consists of two hemispheres , the left and right hemispheres . Each body parts set and serve the opposite , the left hemisphere set the right part of the body and vice versa . If the left hemisphere of the brain impaired the right side of the body will be impaired , and even paralysis . Each front hemisphere is divided into four lobes frontal , parietal , okspital , and temporal . Between the frontal lobe and parietal lobes are separated by the central sulcus or crevice Rolando .
The term refers to structures embryonic telencephalon which later evolved into the cerebrum :

    Dorsal telencephalon or pallium develops into the cerebral cortex
    Ventral telencephalon or pallium evolved into a sub- basal ganglia .

Cerebral cortex
The cerebral cortex is a thin layer of gray consisting of 15-33 billion neurons , each of which is connected to about 10,000 synapses , one cubic millimeter , there are approximately one billion synapses . Communication that occurs between neurons in the form of a long series of signal pulses called action potentials made ​​possible through protoplamik fiber called an axon that can be sent to the remote parts of the brain or body to find a specific cell receptors .
There are six layers of the cortex , the neocortex / isokorteks , arcikorteks , paleokorteks , allokorteks the folds so that the surface becomes wider with a thickness of 2 to 4 mm . Layers of the cortex there are different kinds of nerve centers that control memory , attention , perception , judgment , language and consciousness .the basal ganglia
The basal ganglia is a layer of white . The inner layer contains many nerve fibers , the dendrites and neurites
Large brain is the main nerve center , because it has a very important function in the regulation of all activities of the body , particularly with regard to intelligence ( intelligence ) , memory ( memory ) , awareness , and consideration .
In detail , the activity is controlled in different areas .

    In front of the middle of the gap ( central sulcus ) are the motor area which controls voluntary movement . At the very bottom of the motor cortex have a relationship with speech .
    Anterior regions of the frontal lobe associated with the ability to think .
    In the back ( posterior ) sulcus entralis a sensory area . In this area the various properties of the feelings felt then interpreted .
    Auditory area ( auditory ) is located in the temporal lobe . In this area , the impression or sounds are received and interpreted .
    Visual areas ( vision ) is located at the tip of the occipital lobe that receives the shadow and the shadow subsequently interpreted . As for the taste and smell center is located at the tip of the anterior temporal lobe .
diencephalon
Diencephalon (English : diencephalon , interbrain ) is a part of the brain that consists of :

    mid - diencephalic territory
        pretalamus / ventral thalamus / subthalamic , located below the hypothalamus gland . Nuclei form of zone incerta , thalamic reticular nucleus , and the fields of Forel . Pretalamus patterned SHH signal from the ZLI and after that make different connections to the striatum ( caudate nucleus and putamen ) in the forebrain , to the thalamus ( medial and lateral nucleus group ) in the cerebellum , and to the red nucleus and substantia nigra in the midbrain . Pretalamus suspected to have contributed to the control of consumption patterns including defecation and copulation .
        intratalamika limitan zone that serves as a signaling center like as a barrier between the cerebrum and thalamus and pretalamus .
        thalamus / dorsal thalamus which serves , among others, connect different parts of the cerebrum .
    hypothalamus , a control center of biological time , body temperature and the secretion of hormones and other biological functions . The hypothalamus is located at the base of the forebrain .
    epitalamus
    pretektum
midbrain
The brain is a central part of the brain that has the structure :

    tektum , consisting of 2 pairs of colliculi called corpora quadrigemina :
        inferior colliculi , is involved in auditory processing . Signals received from various brain stem nuclei of the thalamus projected toward the medial geniculate nucleus are called to be forwarded to the primary auditory cortex (English : the primary auditory cortex ) .
        superior colliculi , serve as early visual processing and eye movement control
    cerebral peduncle
        tegmentum is a multi - network of synapses that are involved in homeostasis and trajectory reflex system .
        crus cerebri
        substantia nigra
hindbrain
Hindbrain includes bridge Varol (English : the pons , pons Varolii ) , advanced marrow , and cerebellum . This forms the third part of the brain stem (English : the brainstem ) .

    Varol bridge contains nerve fibers that connect the left and right lobe of the cerebellum , as well as connecting the cerebellum with the cerebral cortex .

    Advanced marrow forming the lower part of the brain stem and the pons bridge connecting the spinal cord . A group of neurons in the reticular formation in the marrow advanced functions to control the respiratory system , and cranial nerve that controls the heart rate are also in the marrow . [ 3 ] It also acts as a central regulator of reflex physiology , air pressure , body temperature , dilation or constriction of blood vessels , digestive tract movement and secretion of digestive glands . Another function is to regulate reflexes , such as coughing , sneezing , and flashing .
cerebellumThe cerebellum is the largest part of the hindbrain . The cerebellum is located below the occipital lobe of the cerebrum . The cerebellum consists of two hemispheres and the surface is grooved . The function of the cerebellum is to regulate the attitude or posture, balance and coordination of muscle movements that occur consciously . In case of minor injury to the brain , can cause disturbances in attitudes and coordination of muscle movements . The movement became uncoordinated




source : http://id.wikipedia.org/wiki/Otak

Baca selengkapnya »

Otak Manusia

Otak (bahasa Inggris: encephalon) adalah pusat sistem saraf (CNS) pada vertebrata dan banyak invertebrata lainnya.
Otak manusia ^[1] adalah struktur pusat pengaturan yang memiliki volume sekitar 1.350cc dan terdiri atas 100 juta sel saraf atau neuron. Otak mengatur dan mengkordinir sebagian besar, gerakan, perilaku dan fungsi tubuh homeostasis seperti detak jantung, tekanan darah, keseimbangan cairan tubuh dan suhu tubuh. Otak manusia bertanggung jawab terhadap pengaturan seluruh badan dan pemikiran manusia. Oleh karena itu terdapat kaitan erat antara otak dan pemikiran. Otak dan sel saraf didalamnya dipercayai dapat memengaruhi kognisi manusia. Pengetahuan mengenai otak memengaruhi perkembangan psikologi kognitif. Otak juga bertanggung jawab atas fungsi seperti pengenalan, emosi. ingatan, pembelajaran motorik dan segala bentuk pembelajaran lainnya.
Otak terbentuk dari dua jenis sel: glia dan neuron. Glia berfungsi untuk menunjang dan melindungi neuron, sedangkan neuron membawa informasi dalam bentuk pulsa listrik yang di kenal sebagai potensi aksi. Mereka berkomunikasi dengan neuron yang lain dan keseluruh tubuh dengan mengirimkan berbagai macam bahan kimia yang disebut neurotransmiter. Neurotransmiter ini dikirimkan pada celah yang dikenal sebagai sinapsis. Avertebrata seperti serangga mungkin mempunyai jutaan neuron pada otaknya, vertebrata besar bisa mempunyai hingga seratus miliar neuron.
Neuron otak mengandung dua jenis asam lemak PUFA (bahasa Inggris: polyunsaturated fatty acids), yaitu asam arakidonat (AA) dan asam dokosaheksaenoat (DHA) yang terletak pada posisi sn2 dari molekul fosfogliserida dalam membran sel neuron.^[2] PUFA dapat terlepas dari fosfogliserida oleh stimulasi fosfolipase PLA-2. Molekul AA yang terlepas akan diproses oleh enzim siklo oksigenase menjadi prostaglandin dan tromboksana, atau diproses oleh enzim 5-lipo oksigenase menjadi lipoksin. Baik AA maupun DHA dapat diproses oleh enzim lipo oksigenase guna membentuk senyawa turunan hidroksi dan leukotriena.

Bagian otak manusia

Pada anatomi otak vertebrata, otak depan  adalah bagian atas dari otak. Pada tahap perkembangan sistem saraf pusat, otak depan berkembang dan memisahkan diri menjadi otak besar dan diensefalon. Jika pada masa embrio, otak depan mengalami hambatan untuk berkembang menjadi kedua lobus ini, maka akan terjadi suatu kondisi yang disebut holoprosensefali (bahasa Inggris: holoprosencephaly).

Otak besar

Otak besar  adalah bagian depan yang paling menonjol dari otak depan. Otak besar terdiri dari dua belahan, yaitu belahan kiri dan kanan. Setiap belahan mengatur dan melayani tubuh yang berlawanan, belahan kiri mengatur tubuh bagian kanan dan sebaliknya. Jika otak belahan kiri mengalami gangguan maka tubuh bagian kanan akan mengalami gangguan, bahkan kelumpuhan. Tiap belahan otak depan terbagi menjadi empat lobus yaitu frontal, pariental, okspital, dan temporal. Antara lobus frontal dan lobus pariental dipisahkan oleh sulkus sentralis atau celah Rolando.
Istilah telencephalon mengacu pada struktur embrio yang kemudian berkembang menjadi cerebrum:

• Dorsal telencephalon atau pallium berkembang menjadi cerebral cortex
• Ventral telencephalon atau sub-pallium berkembang menjadi basal ganglia.

Korteks otak besar

Korteks otak besar  merupakan lapisan tipis berwarna abu-abu yang terdiri dari 15 - 33 miliar neuron yang masing-masing tersambung ke sekitar 10.000 sinapsis, satu milimeter kubik terdapat kurang lebih satu miliar sinapsis. Komunikasi yang terjadi antar neuron dalam bentuk deret panjang pulsa sinyal yang disebut potensial aksi dimungkinkan melalui fiber protoplamik yang disebut akson yang dapat dikirimkan hingga ke bagian jauh dari otak atau tubuh untuk menemukan reseptor sel tertentu.
Terdapat enam lapisan korteks, neokorteks/isokorteks, arcikorteks, paleokorteks, allokorteks yang berlipat-lipat sehingga permukaannya menjadi lebih luas dengan ketebalan 2 hingga 4 mm. Lapisan korteks terdapat berbagai macam pusat saraf yang mengendalikan ingatan, perhatian, persepsi, pertimbangan, bahasa dan kesadaran.

Ganglia dasar

Ganglia dasar merupakan lapisan yang berwarna putih. Lapisan dalam banyak mengandung serabut saraf, yaitu Dendrit dan Neurit
Otak besar merupakan pusat saraf utama, karena memiliki fungsi yang sangat penting dalam pengaturan semua aktivitas tubuh, khususnya berkaitan dengan kepandaian (inteligensi), ingatan (memori), kesadaran, dan pertimbangan.
Secara terperinci, aktivitas tersebut dikendalikan pada daerah yang berbeda.

• Di depan celah tengah (sulkus sentralis) terdapat daerah motor yang berfungsi mengatur gerakan sadar. Bagian paling bawah pada korteks motor tersebut mempunyai hubungan dengan kemampuan bicara.
• Daerah Anterior pada lobus frontalis berhubungan dengan kemampuan berpikir.
• Di belakang (Posterior) sulkus entralis merupakan daerah sensori. Pada daerah ini berbagai sifat perasaan dirasakan kemudian ditafsirkan.
• Daerah pendengaran (auditori) terletak pada lobus temporal. Di daerah ini, kesan atau suara diterima dan diinterpretasikan.
• Daerah visual (penglihatan) terletak pada ujung lobus oksipital yang menerima bayangan dan selanjutnya bayangan itu ditafsirkan. Adapun pusat pengecapan dan pembau terletak di lobus temporal bagian ujung anterior.

Diensefalon

Diensefalon (bahasa Inggris: diencephalon, interbrain) adalah bagian otak yang terdiri dari:

• mid-diencephalic territory
  • pretalamus / ventral talamus / subtalamus, terletak di bawah kelenjar hipotalamus. Nuklei berupa zona incerta, thalamic reticular nucleus, dan fields of Forel. Pretalamus terpola sinyal SHH dari ZLI dan setelah itu membuat koneksi yang berbeda-beda ke striatum (caudate nucleus dan putamen) dalam otak depan, ke talamus (gugus medial dan lateral nucleus) dalam otak kecil, dan ke red nucleus dan substantia nigra dalam otak tengah. Pretalamus ditengarai mempunyai andil dalam pengendalian pola konsumsi termasuk defecation dan copulation.
  • zona limitan intratalamika yang berfungsi sebagai pusat sinyal layaknya cerebrum dan sebagai pembatas antara talamus dan pretalamus.
  • talamus / dorsal talamus yang berfungsi antara lain menghubungkan komunikasi antar belahan otak besar.
• hipotalamus, merupakan pusat pengendalian waktu biologis, suhu tubuh dan sekresi hormon dan fungsi biologis lain. Hipotalamus terletak di dasar otak depan.
• epitalamus
• pretektum

Otak tengah

Otak tengah  adalah bagian otak yang mempunyai struktur:

• tektum, terdiri dari 2 pasang colliculi yang disebut corpora quadrigemina:
  • inferior colliculi, terlibat pada proses pendengaran. Sinyal yang diterima dari berbagai nukleus batang otak diproyeksikan menuju bagian dari talamus yang disebut medial geniculate nucleus untuk diteruskan menuju korteks pendengaran primer (bahasa Inggris: primary auditory cortex).
  • superior colliculi, berperan sebagai awal proses visual dan pengendalian gerakan mata
• cerebral peduncle
  • tegmentum adalah jaringan multi-sinapsis yang terlibat pada sistem homeostasis dan lintasan refleks.
  • crus cerebri
  • substantia nigra

Otak belakang

Otak belakang meliputi jembatan Varol (bahasa Inggris: pons, pons Varolii), sumsum lanjutan , dan otak kecil. Ketiga bagian ini membentuk batang otak (bahasa Inggris: brainstem).

• Jembatan Varol berisi serabut saraf yang menghubungkan lobus kiri dan kanan otak kecil, serta menghubungkan otak kecil dengan korteks otak besar.

• Sumsum lanjutan membentuk bagian bawah batang otak serta menghubungkan jembatan pons dengan sumsum tulang belakang. Sekelompok neuron pada formasi retikular di dalam sumsum lanjutan berfungsi mengontrol sistem pernapasan, dan syaraf kranial yang berfungsi mengatur laju denyut jantung juga berada pada sumsum ini.^[3] Selain itu juga berperan sebagai pusat pengatur refleks fisiologi, tekanan udara, suhu tubuh, pelebaran atau penyempitan pembuluh darah, gerak alat pencernaan, dan sekresi kelenjar pencernaan. Fungsi lainnya ialah mengatur gerak refleks, seperti batuk, bersin, dan berkedip.

Otak Kecil

Otak kecil  merupakan bagian terbesar otak belakang. Otak kecil ini terletak di bawah lobus oksipital serebrum. Otak kecil terdiri atas dua belahan dan permukaanya berlekuk-lekuk. Fungsi otak kecil adalah untuk mengatur sikap atau posisi tubuh, keseimbangan dan koordinasi gerakan otot yang terjadi secara sadar. Jika terjadi cedera pada otak kecil, dapat mengakibatkan gangguan pada sikap dan koordinasi gerak otot. Gerakan menjadi tidak terkoordinasi

sumber: http://id.wikipedia.org/wiki/Otak

Baca selengkapnya »