Neurons: Cells That Produce Electrical Current

Nerves interpenetrating our bodies consist of hundreds, and sometimes, thousands of nerve cells called “neurons.” An average neuron is 10 microns wide. (One micron is equal to 1/1000 millimeter, which equals to 0.000039 of an inch.) Were we able to line up the 100 billion neurons in a human brain, their line would extend for a full 1000 kilometers (620 miles). But this line would be only 10 microns wide, invisible to the naked eye. You can envisage the minute size of neurons with the following comparison: 50 neurons would fit into a period at the end of this sentence5 and 30,000 on the head of a pin. 6

Neurons have been created to carry the electrical impulses throughout the body. The task of most neurons is to receive signals from neighboring neurons and then to transmit these on to another adjacent neuron or to the ultimate target cell. Neurons communicate with one another, carrying out thousands of these processes every second.

We can compare a neuron to an electrical switch that goes on or off, depending on circumstances. On its own, a neuron constitutes only a very small part of the interconnected circuits of the nervous system. But in the absence of these tiny electrical circuits, life is impossible. Professor Werner Gitt of the German Federal Institute of Physics and Technology describes this giant complex squeezed into this small area:

If it were possible to describe [the nervous system] as a circuit diagram, [with each neuron] represented by a single pinhead, such a circuit diagram would require an area of several kilometers... . [It would be] several hundred times more complex than the entire global telephone network.7

As he emphasizes, the nervous system in our bodies functions like a very complex data network, which depends on all the neurons performing their duties to perfection. With the rhythmic, coordinated motion of the impulses from one neuron to the next, each organ, muscle, joint, system and cell performs its functions without any conscious command or supervision from you.

Moreover, although millions of cells die in your body every day, these are expelled from your body in a way that causes no disruption to its balances and functions. Again by means of an impeccable system, new cells replace the ones that have died. In this, there is not the slightest error in terms of timing or measurement. We have no control over these activities, and continue to enjoy healthy lives so long as none of them suffer any disruption.

If you tread on a piece of broken glass while walking barefoot, only a few thousandths of a second elapse between the glass entering your foot and your brain perceiving the pain. During that interval—so brief that it is impossible for you to be aware of it—a message is sent from your foot to your brain, a rapid and flawless communication carried out by neurons. In this way, you lift your foot off the ground before it can be injured any further.

It is completely beyond the bounds of possibility for such a system to have developed spontaneously. However, certain circles who blindly support the theory of evolution seek to account for this perfect order in the human body in terms of random coincidences. We can show just how meaningless these claims are with the following example:

Look at the electrical devices around you, each of which has been specially designed with plastic and electronic equipment, buttons, cables and other components for a specific objective that will make your life easier. Dozens of engineers have worked behind the scenes for a single hairdryer, along with the use of various plants, several branches of science and the designs of experts in the field. The result was a device that's functional and easy to use. No rational person could logically suggest that such a device came into being as the result of chance.

Your body, however, possesses an electrical system far more complex than that in any electrical device. The odds against such a system coming into being by chance are therefore still more infinitesimally remote.

1. Skin 2. Meissner's corpuscles 3. Axon 4. Nodes of Ranvier 5. Schwann cell 6. Direction of nerve impulse 7. Cross-section of spinal cord	8. Cell body 9. Direction of nerve impulse 10. Spinal cord 11. Sensory cortex 12. Brain 13. Thalamus
The time elapsed between your stepping on a nail and your brain perceiving pain is only a few thousandths of a second. During that interval, of which you are unaware, a message is sent from the foot to the brain. You thus withdraw your foot before further damage is done.

Neurons Specially Created to Carry Signals

Processes Squeezed into a Thousandth of a Second

Everything we see, hear and touch turns into electrical signals that move between the brain and the body by way of nerve cells. With our Lord’s knowledge, these processes take place in less than a thousandth of a second.

All neurons contain a nucleus, short fibers known as dendrites that carry electrical signals, and a long fiber known as axon that carries signals for long distances. The nerve cell, which can be as fine as silk thread, can be as long as roughly 1 meter (3,2 feet). Signals sometimes must travel even greater distances along the nerves.8

It’s fair to liken the body of the neuron to a telephone switchboard equipped with advanced technology. However, with its cellular dimensions varying between 0.004 and 0.1 millimeters (0.0001575 and 0.003937 of an inch) and wide-ranging communication mechanisms, this miniaturized telephone exchange has no equivalent in the modern world. In contrast to other cells, neurons contain both dendrites and axons, which give rise to lines of communication that permit the cell to pass its signals along to others. Dendrites receive messages, and axons send them.

A neuron can send an impulse in as little as 1/1,000 of a second. This means that a single neuron can transmit 1,000 nerve signals a second. In general, however, transmission may range between 10 and 500 impulses per second. 9The largest and thickest nerve fibers transmit electricity at a speed of 152 meters (500 feet) per second, and the thinnest of them at about 1 meter (3 feet) a second. 10

Information is transmitted without impairment inside the neuron and forwarded to the correct destination in a most astonishing way. However, the speed at which these phenomena take place is no less astonishing.

Imagine that all the complex systems in your body exist, but that the data transmission in your nerve cells is slower than it actually is: Only hours after the event could you appreciate the beauty of a view, the taste of the food you ate, or that something you touched was hot enough to burn your fingers. You would need dozens of minutes to reply to a question put to you. Crossing from one side of the street to another, or driving, lifting a fork to your mouth, commenting on an article of clothing you like, and countless other forms of behavior could lengthen into situations seriously incompatible with your lifestyle, or which even endangered your life. Lapses in timing between an event you perceive and being able to speak might make life untenable.      Furthermore, this example only considers actions that we undertake voluntarily. The body also performs activities outside our conscious control, such as the beating of the heart. Any slowing in the signals regarding these functions would have fatal consequences. However, through the blessing of our Lord, the Compassionate and Merciful, everything in the human body is just as it needs to be.

In one verse of the Qur’an it is revealed that God has created all things in their proper measure:

God knows what every female bears and every shrinking of the womb and every swelling. Everything has its measure with Him. God knows what every female bears and every shrinking of the womb and every swelling. Everything has its measure with Him.

Dendrites and Axons: The Cables That Surround Our Bodies

Dendrites consist of a large number of short protrusions and are comparable to the roots of the cell. With their branched structure, dendrites receive reports arriving from other neurons and transmit these to the cell body. Put another way, dendrites are like electrical cables, transmitting signals entering the cell. Every neuron possesses up to 100,000 branching dendrites that carry incoming messages to the cell.11

The axons generally bring information from sense receptors to the brain and spinal cord or transmit commands back to the muscles, glands and internal organs. An axon is a long fiber, generally consisting of a single protrusion, that emerges from the cell body and along which signals are sent. Individual axons are microscopic in diameter - typically about one micrometre across (1μm) - but may extend to macroscopic (>1mm) lengths. The longest axons in the human body, for example, are those of the sciatic nerve, which run from the base of the spine to the big toe of each foot. These single-cell fibers of the sciatic nerve may extend a meter or even longer.12

Another striking feature is that a single axon is capable of dividing itself into as many as 10,000 terminals, or end sections. In this way, each terminal can be connected to a different neuron and can permit more than one region to be stimulated at the same time. Since any one single neuron can receive signals from more than 1,000 other neurons, it can carry a million different pieces of information at the same time. 13—an incredible figure. This ability plays a very important role in situations wherein more than one muscle fiber needs to be activated. With these structures, each nerve cell appears like a dense network consisting of long chains.

If the nerves did not have such a structure, then every signal would have to be transmitted in turn. That would slow and seriously impair the rapid, complex transfer of signals in the body.

We can compare the axon terminals at the end of dendrites to plugs fitting into sockets. Thus, in the same way that an electrical current flows from the socket to the plug, the electrical signal continues on between two nerve cells. These connection points at the axons’ ends are attached to receptors on other cells and permit information to transmit between cells. In the way they allow communication between different points in the nervous system, axons are comparable to the links connecting one part of an electrical circuit to another.

Each of these features is essential for our bodies’ communication and coordination. Our ability to lead healthy lives and our very existence depend on all these details functioning flawlessly. One of the aims behind their creation is to exhibit the knowledge and artistry of our Lord. Ours is the responsibility to appreciate the greatness of our Lord and give proper thanks:

... God pours out His favour on mankind but most people do not show thanks. That is God, your Lord, the Creator of everything. There is no god but Him--so how have you been perverted? (Surah Ghafir: 61-62)

The Role of The Synapses in Data Transmission

The gaps or spaces between the axons of two neurons are known as synapses. Communication between the two neurons is established and maintained at these terminal connection points. In the same way that a telephone switchboard permits a large number of callers to talk to one another at the same time, so a neuron can communicate with many other neurons by means of these synapses. Each neuron has around tens of thousands of synapses, 14 meaning that a neuron can establish connections with tens of thousands of separate nerve cells. Even assuming that hundreds of millions of telephone conversations could be transmitted over a single telephone network at the same time, this capacity still lags far behind that of the human brain, which can effect 1 quadrillion (1,000,000,000,000,000) communications by means of the synapse inside it.15Consider how hard-pressed one human being is when working on a 10-line telephone switchboard! You can better understand how a single nerve cell simultaneously carrying out 10,000 connections is evidence of an extraordinary creation.

A neuron collects incoming signals, decides if the total input message is strong enough, and permits its passage to another neuron.16Synapses, the connection points between two neurons, control the distribution of this communication by determining the direction of the signals transmitted.17Triggering or inhibiting signals arrive from various regions of the nervous system, sometimes opening synapses and other times, closing them. In this way, synapses halt weak signals and permit strong ones to pass.

1. Axon terminal fiber 2. Nerve threads 3. Cell membrane 4. Synaptic node	5. Micro-tubules 6. Receptor cells 7. Synaptic sacs 8. Mitochondria	9. Neurotransmitter molecules 10. Synaptic gap 11. Cell membrane channels
Dendrites can be compared to plugs inserted into the axon terminals. In the same way that the electrical current continues flowing from the socket to the plug, the electrical signal between two nerve cells continues on its way.
Synapses: Our Bodies’ Electric Fuses
Nerve cells are connected to one another by special electrical circuits known as synapses, which prevent the body’s electrical system—the brain, spinal cord and nerves—from being damaged. More than 95% of your body’s physiological processes are carried out automatically. We do not tell our stomach, liver, kidneys or lungs to carry out their functions, nor do we command our heart to beat regularly. Our electrical systems depend on that system being protected since it performs a great many functions, and through the mercy of God this protection in our bodies operates flawlessly.

At the same time, they also provide a selective function by choosing and magnifying some of the weaker signals and passing them on—not in one single direction but in many. The way that neurons collect signals and decide to transmit them might lead you to assume they have something resembling conscious human intellect. However, this is accomplished merely by very specially arranged groups of molecules, with no ability to think, nor any organs that permit them to perceive. The ability of a group of molecules flawlessly discharging such vitally important responsibilities is a sign of God’s supervision and eternal dominion over living things.

It is God, Lord of the worlds, Who causes these impeccable processes to be carried out:

I have put my trust in God, my Lord and your Lord. There is no creature He does not hold by the forelock. My Lord is on a Straight Path. (Surah Hud: 56)

Synapses and Constant Electrical Current

Synapses, or the gaps between two nerve cells, are so small that they become visible only when magnified thousands of times. Yet this gap between two cells is also wide enough to prevent any electrical impulse’s leaping from one cell to another. Despite the billions of neurons in the nervous system, they never touch each other in any way. Therefore, from the point of view of the body’s electrical system, every synapse is an obstacle that must be overcome. Yet although they are separated from one another, no lapse is ever experienced in the body’s nerve network, because the signals transmitted electrically along the neurons continue across these spaces between them in chemical form.

Assume that an electrical signal—traveling at 354 kilometers (220 miles) per hour—reaches the end of the axon.18 Where will this stimulus go? How will it get past the synapse to continue on its way? This situation is analogous to coming to a river as you drive along in a car. At this point one has to change vehicles. In the same way that you get out of the car to cross the river in a boat, the electrical signal continues on its journey in another form, that is, in chemical form. Thanks to this chemical communication in the synapses, electrical signals can continue their journeys without interruption.

When a signal reaches the axon terminal, it gives rise to a so-called “message packet” that jumps the small synapse between two neurons and carries chemicals to set the receptor nerves in the neighboring neuron dendrites into action. These messenger molecules, known as neurotransmitters, cross the gap and set the second neuron into action in less than a millisecond.19Neurotransmitters are produced in the body of the nerve cell, are carried along the axon and stored in synaptic vesicles in the axon terminals. Each vesicle contains some 5,000 transmitter molecules,20which chemicals function as trigger or preventive signals. They either impel neurons to produce an electrical impulse, or else prevent them from firing.21

A. Electrical synapse B. Chemical synapse 1. Neuron 2. Direction of impulse	3. Synapse 4. Mitochondria 5. Synaptic gap 6. Connection gap between cells	7. Synaptic sac 8. Open receptor 9. Neurotransmitter 10. Na+ ions 11. Na+ channel
The neuron transmitting a signal and the neuron receiving it meet at the synapse point. A particular electrical signal sets into action the messengers at the axon terminal of the transmitter nerve cell. Sacs full of chemical messengers join with the cell membrane and release molecules into the synapse gap, transmitting the message to receptors on the neuron’s membrane. Different messenger molecules establish connections with different receptors. The harmony among transmitter and receptor neurons is a clear sign of intelligent creation. Electrical signals travel throughout the nervous system, carrying messages from one location to another. Electrical signals have to jump the gaps, or synapses between nerve cells, in order to proceed on their way. In some electrical machines, electricity jumps such small gaps in the form of a spark. The electrical signals in the body pass over the gap in the from of a chemical signal known as a neurotransmitter. In order for us to enjoy healthy lives, these innumerable connections in the brain must be established without the slightest deficiency. Any break or error in connections may lead to a wide range of ailments

Recent research has shown that neurons can contain and release some 100 different types of neurotransmitters. 22 In other words, each neuron is like a chemical factory producing messengers to be employed in communications. Some neurotransmitters are employed in the triggering of electrical signals, others in the halting of electrical signals, and still others in acceleration or deceleration, in frequency-changing and energy storage. Each neuron releases only one or at most, a few different varieties of these neurotransmitters. When a neurotransmitter emerges, it crosses the synapse and the protein receptor on the receptive neuron’s cell membrane sets a protein into motion. At this point, synapses can be compared to a highway by which these chemical messengers are transmitted between nerve cells. The distance between them is approximately 0.00003 of a millimeter (118.10-8 of an inch). 23 Although this distance is very small, it is still a gap that the electrical signals must cross.

The amount of neurotransmitter released is much greater than what’s needed for attachment to the target dendrite. However, as in every other detail in the human body, this excess is an example of very wise creation. The extra neurotransmitters remaining in the synapse block the nerve to prevent the sending of excess signals. If these surplus molecules did not block the nerve, then the time needed for the signal to come to a stop would lengthen into seconds, even minutes. However, the signal transmission takes place in just a fraction of a second. The excess neurotransmitters are absorbed by the axon terminal, and the remainder decomposed by enzymes.24 Just as in a relay race, electrical information is transmitted from cell to cell by means of neurotransmitters that serve as bridges. In this way, the flow of information continues uninterrupted, despite the gaps between the cell extensions.

Yet how do these two independent systems know that they must act together to perform this vital function? In addition, how is that there is no omission or delay in the information transmitted, and for data to be transmitted perfectly to its appropriate destination?

Each of these systems is no doubt a reflection of the knowledge and artistry of God. It flies in the face of logic and reason to expect these miraculous systems to have come into being spontaneously, or to maintain that unconscious cells engage in purposeful activities as the work of chance.