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Showing posts with label Hobby. Show all posts
Showing posts with label Hobby. Show all posts

Ikan gapi Putrajaya untuk dijual (Putrajaya: Guppy Fish for sale)

SOLD OUT. Thanks for your kind buy. :)

Salam.. Saya ada ikan gapi (guppy fish) lebih 200 ekor (termasuk yg. masih kecil).
  COD: Fasa 18R12, Presint 18. * Post: Not preferred BUT can make arrangement for the request :)/Selected area only with delivery charge.


· Pakej: RM 5 = 2 jantan + 2 betina + 10 ekor anak. (COD only)
RM10 = 5 jantan + 5 betina (atau 10 dewasa, bergantung kepada stok)
· Dewasa: RM 1.00— RM 1.50 seekor.
· Anak: RM 0.10 (baby) - RM 0.50 seekor.

Boleh negotiate jika pembelian RM50 ke atas.

I have guppy fish more than 200 (including fries) that I want to sell due to care maintenance problem. 
Package: RM5 = 2 males + 2 females + 10 fries/small fish. (COD only)
RM10= 5 males + 5 females (or 10 adults, depends on stock)
Adults: RM 1.00 - RM1.50
Fries/small fish: RM 0.10 - RM0.50. 

Can negotiate for purchases above RM50.

Accept swap (or plus money if no stock of guppy left) for pair/s (male + female) of:

- Grade A/AA Guppy or
- Black Moscow guppy or
- Albino blue dress guppy or
- Japanese Blue Grass guppy or
- Betta/Guppy/Molly fish food 
** depends on prize of the food/guppies to be compatible with the fish's prize.


To book first, kindly make payment to 7601157972 Nurul Aini CIMB Islamik, and email to inialurunsophie@gmail.com/ SMS 019-3926587 details of payment, ie: time, amount paid, account number or others that prove that the money has been deposited into the account. :)
Contact: Inia 019—392 6587/ Facebook: https://www.facebook.com/inialurunsophie


Other terms and conditions:

  1. Once bought, customers are to be responsible to take good care of guppy/ies bought . 
  2. No refund and no warranty (For postage, if fish dead upon arrival, money will not be returned for postage charge, but the number of dead fish only- if want new replacement/s, custmers are to bear the delivery charge).
  3. Death upon arrival: Need to take photo with the packaging and inform me immediately. 
  4. POstage Important message: Besides from delivery charge, RM3 or above will be charged for oxygen 'purchase' from local fish shop. If courtesy of the fish shop will be cheaper/more expensive/free, it will depends on that. :) Hope they don't charge at all! ;)


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My First Domination in Having Betta Fish as Pet.

Breeding Bunga and Lini the Betta Fish

Friday (11 February, 2011)

- Bought Betta fish. One male, five females from Pasar Tani Presint 2, Putrajaya.

- Named them. Bunga (the only male, priced RM5), Lini, Tali Pinggang, Sakura, Unta & Gorila (priced RM5 for five of them).

Saturday (12 February, 2011)

- Bought small aquarium to put Bunga at ease from small space.

- Put Lini in a bottle and put in Bunga’s aquarium to be familiar with Bunga for later breeding.

- Bunga demonstrate the ability to breed by making bubbles on the water surface.

- Prepare 1 gallon tap water in bigger ‘aquarium’(breeding tank) for them . Let the clorine evaporate in air for 24 hours. Its ok to let it evaporated for 4 hours only. Its a 1 gallon tap water, 24 hours should be sufficient for the evaporation.

Sunday (13 February, 2011)

- Transfer Bunga in bigger space. Decorated the breeding tank of approxiamately 1 gallon of water. It seemed that the depth of the tank was 7 ½ inch. Long approximately 50cm , width approximately 30cm. Enough but too large space? Naah, its ok. Its their ‘large Bungalow’ for the ‘marriage’, mua haha (insincere evil laugh).

- Prepare Sakura as a second female choice to spawn with Bunga, put Sakura in the previous Bunga’s small aquarium and provide it with good food. I fed Sakura beef heart too.

- Put Lini after 1 hour Bunga set his territory and familiarize itself in the breeding tank.

- First 1 hour Lini seemed to tail Bunga whever it swim. After a few hours they happily chase each other and my mother said they ‘fight’ each other when I’m not in present. However, I didn’t see the fighting in my observations. Its okay because they need to know that they are capable of breeding good heredities.

- Now I stop feeding Bunga and Lini food during the spawning.

- Spawning should be done 3 days after providing male and female Betta good, quality food range as preparation for days without food during spawning. I was impatient to experiment breeding my own fish pet. :D Haha. My emotion drive that provoked me not to wait after 3 days providing quality food for the future mother Lini and father Bunga that time = ITS ALL RIGHT IF THE SPAWNING AND BREEDING FAIL BECAUSE THIS IS MY FIRST BREEDING TRIAL. AFTER LINI AND BUNGA ‘EXPERIMENT’ FAIL, THERE ARE SAKURA, TALI PINGGANG, UNTA AND GORILA FOR ME.

Monday (14 February, 2011)

- I was curious whether the couple show the sign of suitability to be spawned.

- In my mind, I want to breed the babies of Bunga and Tali Pinggang, not Sakura like 2 days ago. Tali Pinggang looks elegant. It is black and the tail is red in colour. The babies must be very elegent like their mom too.. (my overdreamed imagination of the breeding thingy)

- Dad said Lini was too small to be breed, he advised me not to have too much hope and faith towards this first breeding trial.

- Bubble nest was built upon the surface. It was the sign of courting.

- Bunga exhibited ‘courting dance’ towards Lini.

- Lini appeared interested and spotted sometimes to bue under the bubble nest.

- I was observing to look for signs that eggs has been produced; ie. Bunga will chase away Lini from the bubble nest.

- It looked as if eggs not produced yet since Bunga and Lini happily ‘play’ together and no sign of aggression towards Lini. Well, Bunga seemed to be a ‘gentlefish’. :P Haha.

Tuesday (15 February, 2011)

- To think that the breeding tank was like a ‘pond’ to the baby fish (I afraid the fries will not be able to swim at the surface when they hatch IF the spawning of Bunga and Lini successful), I transfered the bubble nest (as a precaution – maybe there ARE eggs in the nest) together with Bunga to the small aquarium.

- Sakura, Tali Pinggang, Unta and Gorila were put into the so called breeding tank to play and have a roomie place to live together. At first they fight for territories and they exhibited fightings and tail nippings to each other. Gorila was dominant in the group. Sakura appeared the weakest. Tali Pinggang look like a ‘cool’ fish and diplomatic, sometimes looked like a coward and hideous. Unta is an active female Betta fish. Unta is not too agressive and like to play around.

- After transfered Bunga and it’s bubble nest to the small aquarium, I was questioning whether Lini and Bunga completed the spawning process within these days.

- Tali Pinggang was put inside the aquarium first together with Bunga. Foolish but I thought of spawning those two Bettas. :P haha. The objective to put Tali Pinggang inside Bunga’s aquarium was to see whether Bunga is protective towards the bubble nest or not. If Bunga is protective, then it mean Lini and Bunga’s spawning was a success. Bunga looked cool and flared it’s opucula when it approached Tali Pinggang. The flaring was the sign of two things; one – a fighting sign, and two – a sign of courting. I made a self-answer that Bunga was flirting with Tali Pinggang. Then I took out Tali Pinggang and put together with the other females in the spacious tank.

- Lini was put into the small aquarium with Bunga after Tali Pinggang. Immidiately Bunga chased Lini the entire aquarium quite agressively with lots of flaring while protecting the bubble nest . While chasing away Lini, Bunga looked afraid of Lini coming near the nest. Prior to that, Lini were hiding all the time besides the rocks, to be out of sight of Bunga. Now I know that perhaps there are eggs at the nest. I took out Lini and separate her in the medicated tank because it’s skin look pale and torn.

- I tried to look at the bubble nest whether there were eggs on the bubbles. I failed to see them. I decided to let it be, my hope to have own baby fish was like 25% only.

- Bunga seemed restless when alone. I don’t know whether Bunga needs a female or he was surprised to be back at the small space tank.

Wednesday (16 February, 2011)

- I didn’t satisfied with Bunga. I observed quite a long time at Bunga’s bubble nest. Probing with my eyes to see whether or not the bubble next has my hope.

- Yeayyyy!! I saw the eggs! It was white in colour, not buble-clear look but it’s buble-white pebbles on the water surface!

- My hope and happy feeling was like 390%. Yippie!

- Bunga retrived falling eggs to the nest on the surface. (that’s how I realized the bubble nest PREOCCUPIED by my lovely little eggs).

- I spotted that sometimes Bunga tried hard to get something at bottom of the tank. Maybe the eggs fell to the bottom of the tank and Bunga couldn’t reach it. Poor baby fish.. L

Thursday (17 February, 2011)

- When I woke I found out that Bunga was assisting the fries to swim! The eggs had hatched! I was happy. Happy. Happy.

- My dad was surprised, and so do my mom. My dad didn’t believe that I successfully spawned Lini and Bunga.

- It is a crucial stage; will the fries survive within this 2 weeks?

- I went to a pet shop at Presint 8 to buy bloodworms and micro betta food. I bought an air pump for the fries too. It seemed that the air bubbles produced by the air pump was big and frenzy. Its not suitable to be put to the fries of course. They can’t breath and swim at all with the bubbles and frantic water surface. The fries may end up suffocated of air if I put that air pump into the small aquarium.

- Bunga not to be removed from the tank yet. The fries still not able to swim freely without their father’s help. Bunga shall be removed after 2 days or if it started eating the fries instead of guarding them to the nest on the surface.

- The fries began to swim up and down, their first trial to swim. From the bubbles, I could see their tails. It may not looked like a fry’s tail on that bubbles, but when it swims up and down at the nest, only then it look like a fry. ;)

- I tried to count the fry’s tail amount. Approximately 30 tails available within my sight from the bubble nest. Theremight be more fries inside the bubbles. From this counting, if one-third of the 30’s fries could make it to the 14 days/ 2 weeks, it would be wonderful! I’m looking forward into it.

Friday (18 February, 2011)

- Bunga was dedicated to fulfil its duty as a father.

- Now some of the fries could swim horizontally, not vertically.

Saturday (19 February, 2011)

- Bunga is removed from the breeding tank.

- Some fries not been static under their nest, but rather floating at the open area.

- I put some micro food into the tank so that it could trigger their instict to go close sinking objects.

- Sad news. When trying to change aquarium water of the Bettas, I found out that Gorila is sick. Gorila is put into a medicated tank. It hardly swim to the surface, weak, refuse to eat and the skin look pale and has torn. I suspect it might because of the other 3 Bettas, that are Unta, Tali Pinggang and Sakura. Those three females are tremendously ‘friendly’, not fighting each other.

- After put Lini aside with Bunga for breeding, it’s time to put her back with the other female Bettas. For my surprise, Lini picked a fight with Tali Pinggang only. At first Tali Pinggang ignored Lini, but when Lini keep flaring its opula and biting her (after 7 times trial), Tali Pinggang suddenly became aggressive. Tali Pinggang attacked (flared its opula and tried to bite others) all of the Bettas. I was confused. :P just now before I put on Lini into the scene, the tree females showed beautiful mutual among them.

- Tali Pinggang is isolated, so do the sick Gorila. Right now Lini, Sakura and Unta are living harmoniously in the tank. LOL


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Bulan & Bintang Senyum // The Smiling Moon & Stars

meandthembig

credit to bro shahgazer.. pic lu mmg superb.. from http://dewihati.wordpress.com/2008/12/01/bulan-dan-bintang-itu-senyum-padaku-fenomena-1-dec-2008/



Assalamualaikum warohmatullahi wabarokatuh.

Here is the collection of beutiful picturesque of a phenomenon happened on December 1st, 2008 where on that night, in the sky, there was a 'face', formed by two planets, which is Jupiter and Venus. From the Earth, it was seen like as if the planets been the eyes while the crescent moon looked like a smiling mouth. It was a great view, the greatness of Allah creation. Masya-Allah.. Allah The AlMighty.. I hope you will be amazed too by the beautiful pictures that I took from a few blogs. Enjoyyy.. ;)

smiley

credit to bro shahgazer.. lagi from http://dewihati.wordpress.com/2008/12/01/bulan-dan-bintang-itu-senyum-padaku-fenomena-1-dec-2008/

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


Indahnya Bulan Senyum Bermatakan Bintang

1 Dis 2008 (Isnin) - 1 tarikh yg sgt bermakna & xkan dilupakan. Waktu malam tu mesti ramai yg dpt tgk kecantikan ciptaan Allah SWT. Bersyukur sgt Anis antara org yg bertuah dpt tgk bulan yg sgt cantik sedang senyum.

Al-kisahnya begini, mlm tu around 8p.m Anis dlm bilik, tgh study sikit utk paper Ekonomi (SPM) esok. Agak tension sikit sbb subjek ekonomi bkn shj stkt subjek menghafaz, tp kena faham betul2 konsep ekonomi tu baru boleh nak olah nnti. So, sbb tension tu Anis campak dulu buku atas katil & nak release tension, Anis prgilah dkt tingkap bilik Anis tu. Alangkah terkejut bila tgk 1 permandangan yg sgt CANTIK! Apa lg, terus capai kamera & snap! hehe...

Dari tingkap bilik Anis

Mmg cantik sgt, bulan tgh senyum & bermatakan bintang. Pertama kali tgk pemandangan mcm ni. Rasa bersyukur sgt2 la. Mmg terus hilang tension td..hehe. So, sbb excited sgt Anis pun sms la bbrpa kwn Anis psl bulan ni. Suruh diorg tgk skali bulan tu. Rupa-rupanya kisah bulan senyum ni mmg dah heboh mlm tu smpai masuk berita lagi. Tp xtau berita mana sbb Anis sibuk study, x tgk tv pun. Tp mmg best la.. pengalaman yg xdpt dilupakan. Lps tu, dah puas snap pic & tgk bulan tu.. Anis pun prgilah smbung study subjek ekonomi dgn gembira smbil tersenyum2 =)

Zoom in...

source: http://anishayati.blogspot.com/2008/12/bulan-senyum-bermatakan-bintang.html
---------------------------------------------------------------------------------------------------------------------------

Hait korang semua. Ada dengar citer ni tak? Hmm.. yesterday aku dapat banyak YM message saying that malam tu 1 Disember 2008, keadaan bulan kat langit macam tengah senyum.


Tapi, since kat area umah aku ni mendung, so tak dapatlah tengok keadaan bulan yang tengah senyum tu.


Dari apa yang diceritakan, keadaan bulan umpama tersenyum. Bulan sabit - macam mulut org tengah senyum, dan ada dua bintang - macam mata. So, takde ke sape2 daripada korang yg tengok semalam? Share la sket kat sini.. takpun kot2 la kalo ada sapa2 daripada korang yg ada kamera canggih tu ada amik gambar bulan tuh.. Post la gamba tu..


Teringin gak aku nak tengok macamane gaya rupanya bulan tersenyum.. Huhu..

*Ni la gambar yang aku maksudkan tu.. cantik kan? Subhanallah..

*cantiknya.. view kat kampung..

* Ni view gamba dari Australia..

source: http://www.arakian.com/readblog.aspx?blogID=749

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Neuron from Wikipedia - My Genius Comes from My Brain

Neuron

From Wikipedia, the free encyclopedia

(Redirected from Neurons)
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Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. (A) Denotes Purkinje cells, an example of a bipolar neuron. (B) Denotes granule cells which are multipolar.

Neurons (IPA: /ˈnjʊɹɒn/, NYOO-ron, also known as neurones and nervous cells) are responsive cells in the nervous system that process and transmit information by electrochemical signalling. They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves. A number of different types of neurons exist: sensory neurons respond to touch, sound, light and numerous other stimuli affecting cells of the sensory organs that then send signals to the spinal cord and brain. Motor neurons receive signals from the brain and spinal cord and cause muscle contractions and affect glands. Inter-neurons connect neurons to other neurons within the brain and spinal cord. Neurons respond to stimuli, and communicate the presence of stimuli to the central nervous system, which processes that information and sends responses to other parts of the body for action.

Contents

[hide]

[edit] Overview

Structure of a typical neuron
Neuron

The complexity and diversity in nervous systems is dependent on the interconnections between neurons, which rely on a limited number of different signals transmitted within the neurons to other neurons or to muscles and glands. The signals are produced and propagated by chemical ions that produce an electrical charge that moves along the neuron.

Neurons exist in a number of different shapes and sizes and can be classified by their morphology and function. The anatomist Camillo Golgi grouped neurons into two types; type I with long axons used to move signals over long distances and type II without axons. type I cells can be further divided by where the cell body or soma is located. The basic morphology of type I neurons, represented by spinal motor neurons, consists of a cell body called the soma and a long thin axon which is covered by the myelin sheath. Around the cell body is a branching dendritic tree that receives signals from other neurons. The end of the axon has branching terminals (axon terminal) that release transmitter substances into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron.

The anatomy and the properties of the surface membrane determine the behavior of a neuron. The surface membrane is not uniform over the entire length of a neuron, but is modified in specific areas: some regions secrete transmitter substances while other areas respond to the transmitter. Other areas of the neuron membrane have passive electrical properties that effect capacitance and resistance. Within the neuron membrane there are gated ion channels that vary in type, including fast response sodium channels that are voltage-gated and are used to send rapid signals.

Neurons communicate by chemical and electrical synapses in a process known as synaptic transmission. The fundamental process that triggers synaptic transmission is the action potential, a propagating electrical signal that is generated by exploiting the electrically excitable membrane of the neuron. This is also known as a wave of depolarization.

Fully differentiated neurons are permanently amitotic[1]; however, recent research shows that additional neurons throughout the brain can originate from neural stem cells found in high concentrations in (but throughout the brain) the subventricular zone and subgranular zone through the process of neurogenesis.[2][3][4][5][6][7]

[edit] History

The neuron's place as the primary functional unit of the nervous system was first recognized in the early 20th century through the work of the Spanish anatomist Santiago Ramón y Cajal.[8] Cajal proposed that neurons were discrete cells that communicated with each other via specialized junctions, or spaces, between cells.[8] This became known as the neuron doctrine, one of the central tenets of modern neuroscience.[8] To observe the structure of individual neurons, Cajal used a silver staining method developed by his rival, Camillo Golgi.[8] The Golgi stain is an extremely useful method for neuroanatomical investigations because, for reasons unknown, it stains a very small percentage of cells in a tissue, so one is able to see the complete micro structure of individual neurons without much overlap from other cells in the densely packed brain.[9]

[edit] Anatomy and histology

Diagram of a typical myelinated vertebrate motoneuron.

Neurons are highly specialized for the processing and transmission of cellular signals. Given the diversity of functions performed by neurons in different parts of the nervous system, there is, as expected, a wide variety in the shape, size, and electrochemical properties of neurons. For instance, the soma of a neuron can vary from 4 to 100 micrometers in diameter.[10]

  • The soma is the central part of the neuron. It contains the nucleus of the cell, and therefore is where most protein synthesis occurs. The nucleus ranges from 3 to 18 micrometers in diameter.[11]
  • The dendrites of a neuron are cellular extensions with many branches, and metaphorically this overall shape and structure is referred to as a dendritic tree. This is where the majority of input to the neuron occurs. Information outflow (i.e. from dendrites to other neurons) can also occur, but not across chemical synapses; there, the backflow of a nerve impulse is inhibited by the fact that an axon does not possess chemoreceptors and dendrites cannot secrete neurotransmitter chemicals. This unidirectionality of a chemical synapse explains why nerve impulses are conducted only in one direction.
  • The axon is a finer, cable-like projection which can extend tens, hundreds, or even tens of thousands of times the diameter of the soma in length. The axon carries nerve signals away from the soma (and also carry some types of information back to it). Many neurons have only one axon, but this axon may - and usually will - undergo extensive branching, enabling communication with many target cells. The part of the axon where it emerges from the soma is called the axon hillock. Besides being an anatomical structure, the axon hillock is also the part of the neuron that has the greatest density of voltage-dependent sodium channels. This makes it the most easily-excited part of the neuron and the spike initiation zone for the axon: in neurological terms it has the most negative action potential threshold. While the axon and axon hillock are generally involved in information outflow, this region can also receive input from other neurons.
  • The axon terminal contains synapses, specialized structures where neurotransmitter chemicals are released in order to communicate with target neurons.

Although the canonical view of the neuron attributes dedicated functions to its various anatomical components, dendrites and axons often act in ways contrary to their so-called main function.

Axons and dendrites in the central nervous system are typically only about one micrometer thick, while some in the peripheral nervous system are much thicker. The soma is usually about 10–25 micrometers in diameter and often is not much larger than the cell nucleus it contains. The longest axon of a human motoneuron can be over a meter long, reaching from the base of the spine to the toes. Sensory neurons have axons that run from the toes to the dorsal columns, over 1.5 meters in adults. Giraffes have single axons several meters in length running along the entire length of their necks. Much of what is known about axonal function comes from studying the squid giant axon, an ideal experimental preparation because of its relatively immense size (0.5–1 millimeters thick, several centimeters long).

[edit] Classes

Image of pyramidal neurons in mouse cerebral cortex expressing green fluorescent protein. The red staining indicates GABAergic interneurons. Source PLoS Biology [1]
SMI32-stained pyramidal neurons in cerebral cortex.

[edit] Structural classification

[edit] Polarity

Most neurons can be anatomically characterized as:

[edit] Other

Furthermore, some unique neuronal types can be identified according to their location in the nervous system and distinct shape. Some examples are:

[edit] Functional classification

[edit] Direction

  • Afferent neurons convey information from tissues and organs into the central nervous system and are sometimes also called sensory neurons.
  • Efferent neurons transmit signals from the central nervous system to the effector cells and are sometimes called motor neurons.
  • Interneurons connect neurons within specific regions of the central nervous system.

Afferent and efferent can also refer generally to neurons which, respectively, bring information to or send information from the brain region.

[edit] Action on other neurons

  • Excitatory neurons excite their target neurons. Excitatory neurons in the central nervous system, including the brain, are often glutamatergic. Neurons of the peripheral nervous system, such as spinal motoneurons that synapse onto muscle cells, often use acetylcholine as their excitatory neurotransmitter. However, this is just a general tendency that may not always be true[clarification needed]. It is not the neurotransmitter that decides excitatory or inhibitory action, but rather it is the postsynaptic receptor that is responsible for the action of the neurotransmitter[citation needed].
  • Inhibitory neurons inhibit their target neurons. Inhibitory neurons are often interneurons. The output of some brain structures (neostriatum, globus pallidus, cerebellum) are inhibitory. The primary inhibitory neurotransmitters are GABA and glycine.
  • Modulatory neurons evoke more complex effects termed neuromodulation. These neurons use such neurotransmitters as dopamine, acetylcholine, serotonin and others.

[edit] Discharge patterns

Neurons can be classified according to their electrophysiological characteristics:

  • Tonic or regular spiking. Some neurons are typically constantly (or tonically) active. Example: interneurons in neurostriatum.
  • Phasic or bursting. Neurons that fire in bursts are called phasic.
  • Fast spiking. Some neurons are notable for their fast firing rates, for example some types of cortical inhibitory interneurons, cells in globus pallidus, retinal ganglion cells [12].
  • Thin-spike. Action potentials of some neurons are more narrow compared to the others. For example, interneurons in prefrontal cortex are thin-spike neurons.

[edit] Classification by neurotransmitter production

Neurons differ in the type of neurotransmitter they manufacture. Some examples are

[edit] Connectivity

Main article: Synapse

Neurons communicate with one another via synapses, where the axon terminal or En passant boutons of one cell impinges upon another neuron's dendrite, soma or, less commonly, axon. Neurons such as Purkinje cells in the cerebellum can have over 1000 dendritic branches, making connections with tens of thousands of other cells; other neurons, such as the magnocellular neurons of the supraoptic nucleus, have only one or two dendrites, each of which receives thousands of synapses. Synapses can be excitatory or inhibitory and will either increase or decrease activity in the target neuron. Some neurons also communicate via electrical synapses, which are direct, electrically-conductive junctions between cells.

In a chemical synapse, the process of synaptic transmission is as follows: when an action potential reaches the axon terminal, it opens voltage-gated calcium channels, allowing calcium ions to enter the terminal. Calcium causes synaptic vesicles filled with neurotransmitter molecules to fuse with the membrane, releasing their contents into the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft and activate receptors on the postsynaptic neuron.

The human brain has a huge number of synapses. Each of the 1011 (one hundred billion) neurons has on average 7,000 synaptic connections to other neurons. It has been estimated that the brain of a three-year-old child has about 1015 synapses (1 quadrillion). This number declines with age, stabilizing by adulthood. Estimates vary for an adult, ranging from 1014 to 5 x 1014 synapses (100 to 500 trillion).[13]

[edit] Mechanisms for propagating action potentials

A signal propagating down an axon to the cell body and dendrites of the next cell.

In 1937, John Zachary Young suggested that the squid giant axon could be used to study neuronal electrical properties,[14] being larger but similar in nature to human neurons, they were easier to study. By inserting electrodes into the giant squid axons, accurate measurements were made of the membrane potential.

The cell membrane of the axon and soma contain voltage-gated ion channels which allow the neuron to generate and propagate an electrical signal (an action potential). These signals are generated and propagated by charge-carrying ions including sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca2+).

There are several stimuli that can activate a neuron leading to electrical activity, including pressure, stretch, chemical transmitters, and changes of the electric potential across the cell membrane.[15] Stimuli cause specific ion-channels within the cell membrane to open, leading to a flow of ions through the cell membrane, changing the membrane potential.

Thin neurons and axons require less metabolic expense to produce and carry action potentials, but thicker axons convey impulses more rapidly. To minimize metabolic expense while maintaining rapid conduction, many neurons have insulating sheaths of myelin around their axons. The sheaths are formed by glial cells: oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. The sheath enables action potentials to travel faster than in unmyelinated axons of the same diameter, whilst using less energy. The myelin sheath in peripheral nerves normally runs along the axon in sections about 1 mm long, punctuated by unsheathed nodes of Ranvier which contain a high density of voltage-gated ion channels. Multiple sclerosis is a neurological disorder that results from demyelination of axons in the central nervous system.

Some neurons do not generate action potentials, but instead generate a graded electrical signal, which in turn causes graded neurotransmitter release. Such nonspiking neurons tend to be sensory neurons or interneurons, because they cannot carry signals long distances.

[edit] All-or-none principle

The conduction of nerve impulses is an example of an all-or-none response. In other words, if a neuron responds at all, then it must respond completely. The greater the intensity of stimulation does not produce a stronger signal but can produce more impulses per second. There are different types of receptor response to stimulus, slowly adapting or tonic receptors respond to steady stimulus and produce a steady rate of firing. These tonic receptors most often respond to increased intensity of stimulus by increasing their firing frequency, usually as a power function of stimulus plotted against impulses per second. This can be likened to an intrinsic property of light where to get greater intensity of a specific frequency (color) there has to be more photons, as the photons can't become "stronger" for a specific frequency.

There are a number of other receptor types that are called quickly adapting or phasic receptors, where firing decreases or stops with steady stimulus, examples include; skin when touched by an object causes the neurons to fire, but if the object maintains even pressure against the skin the neurons stop firing. The neurons of the skin and muscles that are responsive to pressure and vibration have filtering accessory structures that aid their function. The pacinian corpuscle is one such structure, it has concentric layers like an onion which form around the axon terminal. When pressure is applied and the corpuscle is deformed, mechanical stimulus is transfered to the axon, which fires. If the pressure is steady there is no more stimulus, thus typically these neurons respond with a transient depolarization during the initial deformation and again when the pressure is removed which cause the corpuscle to change shape again. Other types of adaptation are important in extending the function of a number of other neurons.[16]

[edit] Histology and internal structure

Golgi-stained neurons in human hippocampal tissue.

Nerve cell bodies stained with basophilic dyes show numerous microscopic clumps of Nissl substance (named after German psychiatrist and neuropathologist Franz Nissl, 1860–1919), which consists of rough endoplasmic reticulum and associated ribosomal RNA. The prominence of the Nissl substance can be explained by the fact that nerve cells are metabolically very active, and hence are involved in large amounts of protein synthesis.

The cell body of a neuron is supported by a complex meshwork of structural proteins called neurofilaments, which are assembled into larger neurofibrils. Some neurons also contain pigment granules, such as neuromelanin (a brownish-black pigment, byproduct of synthesis of catecholamines) and lipofuscin (yellowish-brown pigment that accumulates with age).

There are different internal structural characteristics between axons and dendrites. Axons typically almost never contain ribosomes, except some in the initial segment. Dendrites contain granular endoplasmic reticulum or ribosomes, with diminishing amounts with distance from the cell body.

[edit] The neuron doctrine

The neuron doctrine is the now fundamental idea that neurons are the basic structural and functional units of the nervous system. The theory was put forward by Santiago Ramón y Cajal in the late 19th century. It held that neurons are discrete cells (not connected in a meshwork), acting as metabolically distinct units.

As with all doctrines, there are some exceptions. For example glial cells may also play a role in information processing.[17] Also, electrical synapses are more common than previously thought,[18] meaning that there are direct, cytoplasmic connections between neurons. In fact, there are examples of neurons forming even tighter coupling; the squid giant axon arises from the fusion of multiple neurons that retain individual cell bodies and the crayfish giant axon consists of a series of neurons with high conductance septate junctions[citation needed].

Cajal also postulated the Law of Dynamic Polarization, which states that a neuron receives signals at its dendrites and cell body and transmits them, as action potentials, along the axon in one direction: away from the cell body.[19] The Law of Dynamic Polarization has important exceptions; dendrites can serve as synaptic output sites of neurons[20] and axons can receive synaptic inputs[citation needed].

[edit] Neurons in the brain

The number of neurons in the brain varies dramatically from species to species.[21] One estimate puts the human brain at about 100 billion (1011) neurons and 100 trillion (1014) synapses.[21] By contrast, the nematode worm Caenorhabditis elegans has just 302 neurons making it an ideal experimental subject as scientists have been able to map all of the organism's neurons. By contrast, the fruit fly Drosophila melanogaster has around 100,000 neurons and exhibits many complex behaviors. Many properties of neurons, from the type of neurotransmitters used to ion channel composition, are maintained across species, allowing scientists to study processes occurring in more complex organisms in much simpler experimental systems.

[edit] Neurologic diseases

Alzheimer's disease: Alzheimer's disease (AD), also known simply as Alzheimer's, is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes. The most striking early symptom is loss of short-term memory (amnesia), which usually manifests as minor forgetfulness that becomes steadily more pronounced with illness progression, with relative preservation of older memories. As the disorder progresses, cognitive (intellectual) impairment extends to the domains of language (aphasia), skilled movements (apraxia), recognition (agnosia), and functions such as decision-making and planning get impaired.

Parkinson's disease: Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills and speech. Parkinson's disease belongs to a group of conditions called movement disorders. It is characterized by muscle rigidity, tremor, a slowing of physical movement (bradykinesia), and in extreme cases, a loss of physical movement (akinesia). The primary symptoms are the results of decreased stimulation of the motor cortex by the basal ganglia, normally caused by the insufficient formation and action of dopamine, which is produced in the dopaminergic neurons of the brain. Secondary symptoms may include high level cognitive dysfunction and subtle language problems. PD is both chronic and progressive.

Myasthenia Gravis: Myasthenia gravis is a neuromuscular disease leading to fluctuating muscle weakness and fatigability. Weakness is typically caused by circulating antibodies that block acetylcholine receptors at the post-synaptic neuromuscular junction, inhibiting the stimulative effect of the neurotransmitter acetylcholine. Myasthenia is treated with immunosuppressants, cholinesterase inhibitors and, in selected cases, thymectomy.

[edit] Demyelination

Demyelination is the act of demyelinating, or the loss of the myelin sheath insulating the nerves. When myelin degrades, conduction of signals along the nerve can be impaired or lost, and the nerve eventually withers. This leads to certain neurodegenerative disorders like multiple sclerosis, chronic inflammatory demyelinating polyneuropathy.

[edit] Axonal degeneration

Although most injury responses include a calcium influx signaling to promote resealing of severed parts, axonal injuries initially lead to acute axonal degeneration (AAD), which is rapid separation of the proximal and distal ends within 30 minutes of injury. Degeneration follows with swelling of the axolemma, and eventually leads to bead like formation. Granular disintegration of the axonal cytoskeleton and inner organelles occurs after axolemma degradation. Early changes include accumulation of mitochondria in the paranodal regions at the site of injury. Endoplasmic reticulum degrades and mitochondria swell up and eventually disintegrate. The disintegration is dependent on Ubiquitin and Calpain proteases (caused by influx of calcium ion), suggesting that axonal degeneration is an active process. Thus the axon undergoes complete fragmentation. The process takes about roughly 24 hrs in the PNS, and longer in the CNS. The signaling pathways leading to axolemma degeneration are currently unknown.

[edit] Nerve regeneration

Although neurons do not divide or replicate in most parts of the adult vertebrate brain, it is often possible for axons to regrow if they are severed. This can take a long time: after a nerve injury to the human arm, for example, it may take months for feeling to return to the hands and fingers.[citation needed]

Source: http://en.wikipedia.org/wiki/Neurons

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Choosing a Diploma Programme In Early Childhood Education

Introduction
In the field of early childhood education and teachers training, there are skilled based programs and professional and academic programs. Historically, many who entered the teaching profession at the early childhood level, do so because of their love for children and their passion for teaching. However, many of them do not possess any formal training in this field. In order to meet the demands of today’s parents who are more educated and also more demanding, pre school and child care teachers are seeking and equip themselves with the right skills and also the appropriate professional qualifications.

In the past, pre-school teachers may choose to attend some intensive holiday programs and courses offered by trade associations. These courses are designed to provide pre service teachers with some basic skills in handling children. Apart from these programs, there are also many short courses available for those who wish to get an insight to early childhood education. Usually a certificate of attendance is awarded at the end of these short programs. While all these programs can help pre service teachers or potential teachers in getting some basic knowledge, it cannot be equated to a professional qualification or an academic qualification. Thus, the demand for academic qualification especially at Diploma level seems to be increasing.

Choosing a Place to Study
In general, in choosing a place to study for a Diploma qualification in Early Childhood Education, one may consider the following few important criteria:
  1. Registered with the Ministry of Higher Education

    According to the Private Higher Education Act (Act 555), all educational institutions conduct courses leading to the award of certificate, diploma or degree qualification must be approved by the Ministry of Higher Education. This Act seeks to control the management and establishment of private higher education institutions so as to provide quality in higher education for its students.
  2. Registered with the State Education Department

    Upon receiving approval from the Ministry of Higher Education, the college or institution must also need to register with the State Education Department. A Certificate of Registration will be issued and colleges are required to exhibit this certificate in a conspicuous part of their premises. This registration is subjected for renewal every 5 years.
  3. Programmes must be Approved by the National Accreditation Board (LAN)
    Next, the programmes offered must be approved by the Ministry of Higher Education and able to meet all the requirement set by the National Accreditation Board (Lembaga Akreditasi Negara - LAN). LAN functions as a quality assurance body, responsible for ensuring that the higher education provided by the private institutions is of high quality. The Lembaga Akreditasi Negara Act (Act 556) functions to ensure that all courses of study offered achieve a standard acceptable to the norms and conventions of a higher institute of education.

    This is crucial because it provides a benchmark in terms of duration of programme, credit hours, contact hours, entry requirement and lecturers qualifications:
    1. Credit Hours and Contact Hours
      According to the requirements set by LAN, all Diploma programs must be conducted over a period of at least 2 ½ years or 30 months with at least 90 credits hours or 1,260 contact hours.
    2. Entry Requirements
      The entry requirement for all Diplomas in Malaysia is at least 3 credits in SPM or its equivalent.
    3. Lecturers’ Qualification
      All lecturers teaching in private colleges must obtain teaching permits and must possess the relevant academic qualifications in the relevant field. For example, lecturers teaching Diploma programs must have at least Bachelor’s Degree and lecturers teaching Bachelor’s Degree programs must have at least a Master’s Degree.
  4. Minimum Standard
    It is also mandatory for colleges to apply for Minimum Standard certification from LAN after 4 semesters of conducting the programme. This is to ensure quality control and that the courses which have been granted approved previously are conducted accordingly. Here, LAN will send a panel to assess the program content, how it has been delivered, lecturers’ qualifications, facilities, examination procedures and also management of the college. In this visitation, students from various semesters will be interviewed and lecturers will be invited for discussion. Without getting the minimum standard for the course of study, college is not allowed to award qualification to their students.
  5. Accreditation
    Every college should strive for accreditation although in some cases it is not compulsory. Programmes that have been accredited have many advantages compared to those which are not accredited. Graduates of accredited programmes can apply to work with the Government if it has already been accepted by Public Services Department.. These accredited programmes are also of international standing as such are often accepted overseas.
  6. Approval codes
    It is also compulsory for colleges to state the approval code when they advertise their program as this will assist the public to distinguish those that have been approved from those that have not. One example of approval code is KP/JPS/KA5572/10/08. The last 4 digits of the code represent expiring date of the program in month and year.
  7. EPF withdrawal
    Students pursuing diploma programs approved by the Ministry of Higher Education and LAN, are eligible to withdraw money from their Employee Provident Fund (Account II) to settle their school fees. This privilege is very helpful for working adults who have some funds in their Account II.
  8. PTPTN loans (Perbadanan Tabung Pendidikan Tinggi Nasional)
    Likewise, students who are registered in any approved Diploma onwards are eligible to apply for PTPTN loans.
  9. Study Pathway
    Another factor to consider would be the future of the program in terms of continuity. For example before a person is signing up for a Diploma, he or she may wish to consider is there any study pathway available for them to continue into a Degree program if desired.

    Apart from those factors listed above, students and parents should also make comparison about fees, curriculum and syllabus, course outcomes, facilities and overall track record of the college in early childhood education. In summary, there are many Diploma in Early Childhood Education programmes, it is good for students and parents to compare these programmes before making decision on the programme and the college.

Contributed by:
Kolej DiKa,
Petaling Jaya

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