(continued from the previous issue)

Using the distinct groves and folds on the hemispheres as a guideline, a map drawn on the cortex identifies focal points, where the various senses are concentrated, and activities in particular regions. Each of these different colored schematic centers has a specific name and performs specific functions. For example, the region above the neck at the back of the head (occipital lobe) is the field of sight; the sections that coincide with the temporal region is the field of hearing; immediately in front of this, on the left, is (generally) the field of speech; in the forehead region (frontal lobe), on the anterior wall of the middle canal is the initial center of planning of movement; on the top section of the front region is the field of complex movement; immediately behind here, in the middle-side region, is the field of simple movement; the area behind this, next to the hearing field and extending upwards, is defined as the touch receptive field. However, these areas are not confined, but rather spread out, and have a very complex connection network. The duty of the adjoining areas of these regions is to display and decipher the meaning of the signals received from the nerves. As the received signals regenerate past experiences and memories, the object or event sending the signal is recognized. To perform voluntary complex movements, the plan of movement must initially be defined in the mind and then the combination of this plan is conveyed through my nerve fibers to the movement regions. As complicated activities in humans, such as talking, and activities that involve the sensory integration mechanisms are miracles in themselves, it is quite astonishing that certain people claim that humans evolved from apes, later learning how to speak. The spinal cord (medulla spinalis) that extends from the skull in the form of a long cord, is the central nervous system sending signals to the body regions under the neck. The grey matter of the brain is located on the surface, while the white matter lies beneath the cortex; however with the spine, the butterfly shaped grey matter is inside, and the white matter on the surface covers the grey matter. In this central nervous system, all of the sensual messages that are received from the entire peripheral system, in particular from your skin and muscle, are immediately connected with the synapses or connections of the movement cells, and thus a spinal reflex is produced. As a section of the connecting cells (synapses) responds with a reflex, the other section transmits the signal to me to determine the appropriate voluntary response. For instance, if you tread on a nail, as the nail goes into the foot, a signal is transmitted by the sensor fibers to the spine, and to avoid a loss of time, the spine immediately signals the movement nerves before me, and a command is transmitted to your muscle you to raise your foot. And after your foot is saved by instant reflex, you begin to perform the other conscious activities, for example; you avoid putting weight on the foot, and bandage the wound if it is bleeding.

31 pairs of nerves (right and left) emerge from the spinal cord; 12 pairs from the brain area lay beneath the skull. These are all nerves that emerge from the central nervous system, and are distributed to various organs of the peripheral nervous system. All of the head nerves that emerge from the skull, with the exception of the tenth nerve, called the vagus nerve, control activities related to movement and senses in the head and neck region. Each of the 31 nerves exit from a space in the side of the vertebrae, and each of these nerves has two roots, an afferent nerve (sensual nerve), and an efferent nerve (movement nerve). These roots join immediately outside the spinal cord, and form the cords that carry the sensual and movement nerve fibers. These nerve cords are distributed in a plan and system that is specific for each organ. For example, the receptor sensor cells that sense a needle pricking your finger transmits this signal to the spinal cord through the receptor cell of the arm. The responsive reflex of pulling the hand away, a reflex from the spinal cord, is sent to the arm and hand muscles, and you pull your hand away. This is an example of a simple reflex. The movement nerve cells of the peripheral nervous system are divided into two, the somatic nervous system, which is distributed to the skeletal muscles, and the autonomic nervous system, which is distributed to the inner organs. Whilst the majority of the activities of the somatic systems occur voluntarily at the conscious level, the activity of autonomic systems is mainly involuntarily, or below the level of consciousness. The autonomic nervous system controls the smooth muscles of the heart, glands, blood vessels, respiration, digestion, urination and reproduction systems without our even realizing it. Dear Peter! Could you manage to do all this if you were in control? Your self control can only intervene until you place food in your mouth. Then the digestive secretions, the stomach and bowel activity, and the excretion of waste are all conducted automatically, totally beyond your control. Your breathing continues while you sleep, your kidneys never cease to function, your heart never rests, and your liver never relaxes while you sleep; your pancreas continues to produce insulin. All of your internal organs and blood vessels continue to function with the smooth muscles whenever necessary. And all this activity is conducted without you even being aware of it. If you tried to do all this, you would become exhausted within five minutes, lose interest and become unable to cope.

The nerve cords of the autonomic nervous system are divided into two, the sympathetic and the parasympathetic. These two systems have been created in such a way that they respond in opposition to one another, and every organ is provided with a stem from both. Therefore, no organ of the body is left uncontrolled. Whilst one signals and encourages the organ to function quicker and generate more outcomes, the other acts to the contrary, sending signals that encourage the organ to slow down. In which case, with these two contrasting signals, the organ protects its optimal functioning tempo according to the situation and conditions. The sympathetic system generally responds in cases of stress and shock, preparing the body for the effects of such situations. For example, an increase in your blood pressure, blood-sugar level, and perspiration, the dilation of your pupils, and an increase in the flow of blood in your muscles all occur from the effect of the sympathetic fibers. The parasympathetic system sends adverse signals, such as reducing blood pressure and so on, so that the organs return to their neutral state and continue their normal functions.

From the very beginning I have described many of my sections and signals, but I have not yet told you about my key to life, my nerve cells, and how my nerve cells function. 30 billion cells, known as neurons, are the actual units that function in every part of my system. A neuron has a cell body and emerging filaments like tree branches. The single thicker filament like the tree trunk is called the axon, and the thinner filaments that emerge in larger quantities like tree branches are called dentrites. The nerve signals advance from the axon to the dentrite in the form of an electrical pulse. In the space between the connection point (synapses) of a nerve cell axon and the other cells, the dentrite, a chemical substance, called the neurotransmitter, is released. When these substances, in the form of neuropeptides, amino acids, acetylcholines, and monomines, reach the wall of the opposite cells, it an electrical pulse is immediately ignited in the dendrite. Just like a row dominos, falling down one after the other, or football fans performing the Mexican wave, a wave-like effect is generated and these electrical messages are fired with great speed from one end of the cell to the other, advancing in the form of tiny electrical pulses to be transmitted to neighboring cells. While a cell at rest has a potential of 70m V, the action potential of up to +30 – +40m V can transmit all types of information. Every cell can transmit up to 1,000 signals per second.

While you still do not recognize the true value of what you call the memory, which records hundreds of experiences every day, various theories are presented regarding how this bank which stores information in your brain actually functions. But we all know that the answer to this question lies within the millions of neurons that constitute me. Just as all of the senses, thoughts and actions occur from electrical and chemical signals that are transmitted from one cell to another they are presumably recorded in the same way, that is, with electrical and chemical signals.

It is difficult to define a precise center for the boundaries of the memories in me; memory could be interconnected with all of my regions. The storing of certain memories, some voices, visions, smells, or dreams, or the sense of resentment, anger or joy, is all carried out in different forms. You could not even begin to imagine the greatness of the memory storage! I have two types of memory, one short and one-long term. In my short term memory, I can store up to between seven and nine different things at any one time. Nothing remains in my short-term memory for more than a few minutes. Everything that you remember after this is stored in my long-term memory. In my long-term memory things can remain for days, months or even years. Everything you know and learn is stored in your long-term memory. By the time you are eight years old, the information in your memory is enough to fill one million pages. However, this is a mere drop in the ocean; the long-term memory is so vast that it can never become full. Even when you reach a hundred, I will have the capacity to store new information, so never assume that you are overloading a child’s mind and never deprive them of education…Some presumptuous people say; “Never force a child to memorize at a young age, it will affect the brain.” Do not believe them! The learning of foreign languages, the Qur’an and religious education is recorded in my memory by electric pulses and this is so much easier and healthier in the early stages of life. In fact, such activities at a young age can even strengthen the memory. The event called ‘recollection’ is the repeat of the electric pulse codes that are recorded at the actual time of an event. Occasionally you try to remember a person’s name, and although the name is on the tip of your tongue, you just cannot remember. You struggle and eventually give up. Then suddenly, two days later the name comes to your mind. You are quite puzzled and of course pleased that you have remembered, but have you ever wondered how this happens? As you try to remember, you control each of my nerve cells individually, because you are not sure where you placed the files that bear this information. But you are unable to find which section of the millions of cells bears the information. As you have not used this information often, or because you did not consider it to be important, you did not register it in a particular place. But you would never forget your father’s name, as it is important to you and use it often, so the file is in front of you constantly. Well, you get frustrated at not being able to remember and stop searching; however, what you call the subconscious is in fact a much more mysterious mechanism. It begins to search without you being aware of it. Then to your surprise it produces the file two days later. The subconscious is a very mysterious place, it affects everything about you. Only the most sincere feelings are recorded in the subconscious; no veil, no hypocrisy, only actual thoughts are recorded. And also events that deeply affect you, the sad or bad memories you experience, and of course sins…The subconscious is what causes the sense of guilt or an inferiority complex; this is reflected in much of your behavior. But problems like guilt or an inferiority complex are something we can change; it all depends on you. If you are a person who has self-control, you perform good, favorable deeds, and are continuously patient; thus you can eventually renew the contaminated sections of your subconscious so that it will not upset you anymore. Indeed, this is the reason why, of all the creatures on earth, only humans were blessed with the sense of remorse and faith. If you suppress feelings of guilt and sin in the subconscious, the autonomic system affects the organs without you even realizing it; the thalamus, hypothalamus, or the pituitary gland (hypophsis), which are small in size, but bear a great responsibility; eventually this disturbs the balance of the whole body and you become ill. Although this may not be an organic complaint at first, due to psychosomatic symptoms which are caused by suppressing your subconscious, over time this will affect the functions of one of your organs and you become ill. Of course the exact opposite is also possible, with inspiration, pleasant thoughts and good actions the positive signals transmitted to the affected organ may possibly be the means to recovery.

Dear Peter! I have so many more facts and mysterious functions to describe to you, but unfortunately the pages here are not enough. Well, I suppose I must stop somewhere. I really wanted to talk to you about a number of different things, like dreams, mental illnesses such as Parkinson’s, Alzheimer’s, strokes, sleep, hypnosis, and the damage caused by drugs. However, each of these subjects is so vast, and many of them have already been explained in previous issues, so for now I will leave it to others to describe these subjects to you, and say my last words…

Dear Peter!… While your hand is writing and reading these words, or explaining what you have read to your friends, or learning all this information and passing it through the filter of thought, you are constantly using my nerves and my systems. There is not a single moment where I am not informed of events that occur in your body. Who knows just how much of the mysteries in me you will use in order to rise to the peak of accomplishment with the blessings that have been bestowed upon you by the Creator. Even the greatest computers made by human beings are mere toys compared to me. Nevertheless, the knowledge of engineers and craftsmen which design, plan, and place every piece into these computers with total accuracy is only possible because of me. Presumably you are not denying those who designed, constructed, and made the computer operate, are you? In which case you should thank God, the One who created me, an organ whose capacity exceeds that of thousands of computers, with His eternal power and wisdom; always remember to use me in good, blessed, and honest actions!…May God protect you!…

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir. 

When we have been sitting or lying for a long time we can suffer from orthostatic hypotension due to an insufficient operation of the sympathetic nerves.

When we are lying down, the blood pressure in our arteries is pretty much equal throughout the body. When we stand up, the blood pressure is affected by the gravity and increases in the vessels under the heart, while decreasing in the brain. If we lie down again, the blood pressure in the arteries balances once again. If these changes cannot be naturally controlled, then we may suffer an increase or decrease in blood pressure, which could result in a fatal injury.

There are baroreceptors in the walls of main arteries whose tasks are to measure constantly the blood pressure and to send data (electrical signals) to the brain, informing it about the blood pressure in the body. These baroreceptors are located in the aorta as it leaves the heart and in the carotid artery as it enters the brain. With the onset of hypertension, the frequency of the signals that are sent to the brain increases and this drops in case of hypotension. The center of vessel movement in the brain, with regard to the frequency of electrical signals it receives, perceives a low or high blood pressure.

In the brain is a vasomotor center; this continuously controls the blood pressure and regulates it. This center constantly receives data about blood pressure. If the pressure decreases, the signals of the sympathetic nerve increase. If the pressure increases, the signals to the parasympathetic nerves are suppressed. As a result of sympathetic irritability, the heart begins to beat faster and stronger. It pumps much more blood in a unit of time, and thus the blood pressure increases. The arteries and veins also constrict and owing to this constriction in the arteries, the blood pressure increases further. As a consequence of constriction in the veins, the extra blood that is stored inside the veins is pumped into the heart. Now, as the heart is receiving greater volumes of blood, it works faster and contributes to the increase in the pressure. In the meantime, as a result of the suppression of parasympathetic nerve signals, the heart contracts faster and stronger, thus pumping much more blood.

As the blood pressure rises, the mechanism which is in charge of reducing the pressure via vasomotor center is triggered. While pressure is applied to the sympathetic nerves, the signals that are being sent to the heart and vessels decrease. Thus, the rate of systole and the amount of blood which is being pumped decreases. As the arteries receive less blood the volume of blood in the system falls off and as the arteries and veins expand, the blood pressure falls. Due to the dilatation in the veins, the volume of blood which is sent to the heart also decreases and as a result the heart pumps less blood and the blood pressure drops.

However, by triggering the parasympathetic nerves, the signals that are sent to the heart increase. This helps to slow the heart down and ensures that there is less blood pumping through the system. As a result, the blood pressure which has been reduced via the sympathetic system is reduced even further with the parasympathetic system. At this point, it is necessary for there to be a rapid drop in blood pressure, which is provided by the simultaneous functioning of different mechanisms.

We cannot control this system and it acts extremely rapidly and with great elegance. Even in the systole period, when the heart is pumping the blood and there is a short and sudden increase in pressure and in the diastole period, when the heart relaxes and there is a short and sudden decrease in pressure, the system is in charge and functioning at every second, operating to increase the hypotension and to decrease the hypertension. The average healthy human heart beats 70 times per minute. Consequently, there are 70 systole and 70 diastole stages every minute; thus a normal balance can be maintained by decreasing the pressure, which increases 70 times every minute, and by increasing the pressure, which decreases 70 times every minute; this is how the body maintains a normal balance. In other words, this system functions 140 times every minute. Is it possible that this system, which operates throughout our life, a system that we are not aware of, a system that is so sensitive and vital to our lives, a system the details of which have only recently been understood after centuries of observation could be nothing more than a coincidence?

The pressure regulating system mentioned above carries out other important tasks while we are sitting and standing as well. The amount of blood going to the brain is related to the maintenance of a difference in blood pressure between the arteries and veins and to the recirculation of blood. In connection with hypotension, the pressure in the veins to the brain decreases, in order to partially compensate for the decrease in the arteries. By preventing a decrease in the difference of pressure (perfusion pressure) between the two systems, the continuity of blood going to the brain can be maintained.

In addition, a small decrease in the blood going to the brain can lead to an increase in acidity and carbondioxide in the brain tissues and to a decrease in oxygen; this results in the dilatation of the blood vessels in the brain. When these systems go into action anyone who is not suffering from orthostatic hypotension will have a stable amount of oxygen consumption in the brain when they stand up, and thus not experience dizziness.

In fact, scenes from karate movies are wonderful displays of the perfect functioning of this system. In such scenes, the fighter will jump up, and then suddenly fall to the ground; he will then suddenly spring up and performs different moves. Certainly with every movement, the blood pressure changes suddenly, but as a sign of the Creator’s mercy and grace, the body is able to maintain a balance. Should not the person watching these scenes stand in amazement, thinking: “Oh my God, what an incredible order! How great is Your knowledge, power, wisdom and art!”

As mentioned at the beginning of the article with reference to an actual sad incident, when a person whose sympathetic system is not functioning normally suddenly stands up, they can suffer from dizziness and perhaps even faint due to irregular blood pressure.

For patients suffering from orthostatic hypotension patients, it is important that they do not stand up rapidly. In addition, exercises that encourage the use of leg muscles before standing up will help pump blood towards the brain.

Pause for a minute… What would happen if this miraculous system did not exist? Consider how much time it would take you to merely get out of bed every day!

Finally, I have come to say goodbye to you. As you probably know, there is a saying “Leave the best till last.” I am the greatest of all the organs and systems that have described themselves to you so far. I am an integrative system that forms a chain between every organ in your body. Just as your veins are spread out to carry nutrients and oxygen to every part of your body, I also embrace your entire system like a network, without leaving the tiniest space; I am informed of everything that goes on inside your body. Even if a tiny insect settles on your arm, you sense it immediately. I make you aware of a tiny drop of sweat on your body. I induce pain in suitable measures to inform you of any illnesses in your inner organs. In fact, I not only inform you, I also warn you to seek help.

However, it is hard for me to describe myself. When you hear the words “nervous system,” what comes to mind is a cluster of cells called neurons. But this is a great mass of cells, and we should always remember that we are referring to the most complex matter in all of creation. The very important main nervous systems, which are very close to one another, are the huge masses positioned beneath the skull, the extensions of my system and secondary nervous system; this latter is spread out through various regions of the body. It would take up too much of your time to describe each region and branch of my system individually to you each month, but in this way I could prove what a perfect and incredible duty each of them performs within your body. However, I will try to explain the subject briefly to avoid boring you. Nevertheless, please forgive me if I ramble on too much; we are describing the most excellent organ created by God so it is inevitable that there will be some complicated matters that need clarification.

Instead of allowing each of my sections to describe themselves to you individually, I will speak on their behalf as the “brain.” It may be easier for you to understand the system if we divide it into two. One of them is me and the nervous system which I lead; we can briefly describe this as the thalamus, hypothalamus, cerebellum, the medulla, and the spine. The other part is the peripheral nervous system, which emerges from the central nervous system and is distributed, rather like fiber optic telephone cables, throughout the entire body. In addition to me, the brain, and my two large cerebral hemispheres, there is another smaller section, which is known as the brain stem. The brain and its cerebral hemispheres and the sections of the brain stem which are protected beneath the skull (the cerebellum, medulla, thalamus, and hypothalamus) are very important. The spinal cord, which is also a part of the central nervous system, however is not in the skull, but positioned within the vertebrae that constitute the spine. Due to its connection with the central nervous system, any damage to the spinal cord can endanger life.

Although damage to regions of the body where the nerves are distributed from the central nervous system may cause paralysis, or functional disorder for the specific organ, such an incident is not life threatening.

If you recall, when the heart and circulation system described themselves they boasted – indeed the veins also seemed to brag a bit when they stated that they measured 75,000 miles (long enough to go around the world almost three times). But the nerves are approximately 477,000 miles, long enough to stretch from the earth to the moon, and back again… the nerves which are distributed throughout the various parts of your body measure 250,000 miles, and the total length of the central nervous system is 228,000 miles. Almost 200,000 signals pass through just one cell at a time, which means that every moment thousands of signals pass through millions of my cells all throughout your body, and flow from the central nervous system to the whole body and then back to the central nervous system. There are about 30 billion cells in my system. 10 billion of these cells are in the cortex, 10 billion in the cerebellum, and the remainder forms the structure of the nerves and other sections. As a comparison, a fly’s brain contains 100 thousand cells, and a rat’s brain has 10 million cells. The total number of connections and contact points (synapses) that my 30 billion cells use to send and receive signals is 100 trillion. The number of combinations that these connections can establish to send signals to one another is greater than the number of atoms in the universe. At the beginning of a thinking process, the number of cells activated is between 10 and 100 million, and according to the depth and intensity of the activity, these figures can increase to astounding numbers. Every second 4 billion signals are exchanged between the left and right hemispheres. When you were an embryo, just a few weeks old, I consisted of 92% water. When you were first born, the ratio of water was 90%. And when you were fully developed, the water ratio remains at 77%. Peter! Can you imagine, a heap of mass consisting of 77% water, the remainder made up of various element. Our Lord, the bearer of eternal power places me in you, in the head of the most honorable creation, and with me you form civilizations; you invent and discover. And even more important, with my mediation you have the ability to contemplate and reach your Creator. What we are learning about here is how with me you are able to recognize the wisdom of the entire universe. The electric signals of the various sense organs, such as the eyes, ears, nose, tongue and skin, all of which have previously described themselves, are transmitted by the receptive cells on various wavelengths; these are then conveyed to you in the form of sight, noise, smell and taste. In fact I am inducing you to write these words at this very moment. The evaluation of everything you do passes through me, but you are not even aware of it. When you walk, eat, talk, speak or sleep, the information I receive from every part of your body is reviewed and responded to in a suitable manner. Dear Peter! Could a single nucleus of a single one of my cells possibly position itself alone?

The Lord has created me so magnificently that you are still only aware of a very few of my mysteries. Each of the sections that I mentioned above has a distinct and important vital function. On their behalf, I will briefly explain their duties: The cerebellum is the nerve center from which the harmony of balance and muscle movement is controlled. As this section of me has no sense of perception, it is impossible to voluntarily change the functions of this region. The pyramid shaped medulla oblongata, which connects the spinal cord to the midbrain and the pons; the latter constitutes the other end of the brainstem through a hole in the back of the skull in the form of the spinal cord and enters into the vertebral column. Here, there are many nerve centers which regulate autonomic nervous system activity, such as the heart rate, breathing, and digestion process. This is also the center from which the reflexes are controlled, the body’s inner environment is regulated, and this center, working with the cerebellum also controls movement and coordinates signals received from the nerves of inner organs. Moreover, activities such as excitement and sleep are also controlled here in collaboration with the thalamus.

The thalamus lies between the brainstem and the hemispheres of the brain, performing a function rather like a junction or relay station. This section gathers all the signals sent by the sense receptors, except for those from the olfactory (smell) receptors, and conveys these signals to the cortex reflecting the information; there is also a role played in consciously identifying sensations such as pain, touch and noise. There is also a role played in the sensory changes that occur with the perception of senses in our consciousness and awareness, as well as in the regulation of sleep and paying attention. The hypothalamus, which is located below the thalamus, is an important center that controls sexual senses; the sensations of pain, pleasure, hunger, and thirst, as well as blood pressure, temperature and other functions of the inner organs. It also performs the important duty of regulating hormone release. The nerve fibers that enter this center, which is the location of a very complex network of nerves coming from the olfactory bulb, thalamus, and the frontal lobe, reach the autonomic nervous system, the reticular formation in the stem section, and the posterior lobe behind the pituitary gland (hypophysis). The pituitary gland, one of the most important systems that earlier described itself in the endocrine system, produces hormones that stimulate secretion in the anterior section, as well as the oxytocin and antidiuretic hormones which are stored and released from the posterior pituitary.

On the base of the deep grove that separates the two hemispheres of the large brain there is a callus-like body; this is a bundle of axon (nerves) called the corpus callosum which connects the two hemispheres. Because the nerve fibers cross and change direction in the medulla, the left side of the brain controls your right side, and the right controls your left. Although my two hemispheres may look like a reflection of one another, there are some variations in their duties; for example, the left hemisphere controls speech, but the section which controls the perception of location is in the right hemisphere. Whilst you use the left hemisphere for duties that must be performed in a specific order (activities such as adding and subtracting or buttoning a shirt), you use the right hemisphere in thinking with images (for example, mapping the route from your home to the market). If the callus substance that connects my two hemispheres did not exist, there would be no communication between the two, therefore, you could read the word “fish,” but you would not be able to picture the image of a fish in your mind without the right hemisphere to achieve this.

The brain, the grey-colored mass of folds and grooves that covers the top of my anatomic hemispheres, the region where the main stems of my cells are found, is called the cortex or grey matter; the lighter colored matter that lies beneath this, the region where the axons (stems of neurons) are found, is called the white matter. My cortex region, which is composed of six layers of cells, is the center where the sensory signals are received and analyzed and where voluntary muscle movement is controlled, while also being the center of activities, such as learning, reasoning, and remembering. My two hemispheres, the focal point of conscious activity and thought that forms the large brain, constitute 85% of the whole brain. When you were first born I weighed 400 grams, but I grew very quickly, and by the time you were a year old I weighed 800 grams. When you were four years old, I weighed 1,200 gr. However, my growth began to slow down after the age of seven, and when you reach twenty, I will weigh approximately 1,379–1,434 grams. When you begin to pass your first youth, my weight begins to decrease every year by 1 gram, so when you reach seventy-five, I would have shrunk in comparison to when you were twenty. The reason for this decrease in weight is that approximate 50,000 neurons die, or cease to function daily, after you reach the age of twenty. The body cells of the cartilage, bone, skin, ligaments and the liver divide, regenerate and increase in number; however, the nerve cells that are part of me continue to increase until they reach the figure set out for you when you were formed in your mother’s womb; they then lose the ability to segregate. So if there is any damage, relative functions fail because the cells in that region have died. Then the question arises: As there is no increase in the numbers of cells, how does the weight continue to increase until the age of twenty? Well, there is not an increase in the numbers of cells; rather, there is an increase in the number and growth of connections between the cells and this is how my weight increases. Of course, nutrients are added to build and stimulate these connections. Subsequently, with age these connections begin to decrease. With ever experience you have, all the things that you learn or see during your youth these connections increase, and in turn this increases my capacity for thought and reasoning. If you continue to activate your brain by reading, writing and other social activities in old age, these connections continue to increase. Even if there is a decrease in my cells, you are able to continue your usual activities without losing any functions of the brain. But as soon as you say that is enough, it is time for a rest, my cells begin to withdraw their connections immediately, and in time you will certainly see the difference in my capacity. If the cells in my central nervous system are injured or damaged, they cannot repair themselves. However, if the cell bodies of my cells in the peripheral nervous system are not damaged the stems are repairable.

Thanks to this special feature if a severed arm, leg or finger can be carefully replaced with microsurgery, the nerves can repair themselves, and the limb will continue its normal functions. The visible cause of this characteristic is found in the nerves of the arms and legs, but not in the brain or spine, is the casing that surrounds this bundle of nerves that transmits signals for the cells to grow. Even with the greatest of techniques, no surgeon could sew the severed nerve fibers. However, thanks to the nerve casing that holds these fibers together (like the plastic that covers the electric cable, consisting of thin wires) the severed limb can be replanted. Then with guidance from this outer casing, each of the hundreds of fibers found inside grow 1 mm every day, and in a period of between 1 month and a year, they will begin to function again.

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir. 

He was born in Cordova in 52OAH (1126) and named after his grandfather Abu al-Walid Muhammad ibn Ahmad ibn Rushd, who died in the same year. His grandfather was the Chief Judge in Cordova and the foremost authority in Maliki jurisprudence. To distinguish him from his illustrious ancestor, Ibn Rushd was later known as Ibn Rushd al-Hafid (the grandson).

Cordova, where Ibn Rushd grew up, was a thriving centre of all the diverse arts of civilization and culture attracting many great scholars from around the then known world to its wonderful libraries. Ibn Rushd studied and memorized the Qur’an and the Muwatta of Imam Malik. He was an excellent student of jurisprudence and quickly qualified to give legal opinions and sit as judge.

Following his work in the sciences of law, language and Hadith, he went on to study mathematics, astronomy and astrology and then medicine. He was a friend to the most prominent thinkers and writers of his age: Ibn al-Tufayl (d. 1186/6), author of the famous allegory Hayy ibn Yaqzan (said to have influenced Robinson Crusoe ); the philosopher, Ibn Bajja (Avempace in the West, d. 1139); the great jurist and judge Abu Bakr ibn al ‘Arabi (d. l148); the famous physician Abu Marwan ‘Abd al-Malik ibn Zuhr (Avenzoar in the West, d. 1161) and his son Abu Bakr (d. 1198).

Ibn Rushd served as a judge in Ishbiliya (Seville) in 1171 and then in Cordova two years later. His reputation for wide knowledge, correctness and fairness in giving verdicts, led to his appointment as Chief Judge. His book Bidayat al-mujtahid wa nihayat al-muqtasid (The reference for the searcher and the resort for the fair) remains an important reference for students of jurisprudence and is still taught in universities to this day. Although he was a Maliki he used the ideas of other schools of thought. Because he had so many activities and interests besides his public duties, Ibn Rushd had to organize his time very fully: he spent his days working as a judge, teaching, and in academic discussion with other scholars; he reserved his nights for reading and writing.

His friend Ibn al-Tufayl wrote to invite him to visit Marrakech, the capital of the Muwahhidun (Almohades) who had established a powerful and stable state in North Africa after they took over from the Murabitun (Almoravides), and were famous for their patronage of scientists, physicians, theologians and philosophers. Ibn Rushd’s intelligence, learning and ideas so impressed the ruler, Abu Yusuf ‘Abd al-Mu’min, that he was appointed to reform the educational system. This he did successfully before returning to Cordova.

When Abu Ya‘qub ibn ‘Abd al-Mu’min came to power, he appointed Ibn Rushd as his personal physician after Ibn Tufayl. Ibn Rushd held this post for a year (1183) when he was appointed as Chief judge. His success provoked court envy and he was falsely accused of heresy, in particular that he adhered too closely to the doctrines of Aristotle. He was indeed a supporter of Aristotle’s doctrines after these were properly reformed and adapted to Islam. Ibn Rushd fell out of favour at the court and was ill-treated. His books on philosophy were burnt, though his works on medicine and theology were not censored. When Abu Ya‘qub discovered he had been misinformed, he tried to invite Ibn Rushd back to apologise to him, but he was too late. Ibn Rushd died on 9th Safar 595AH (December 1198).

His writings

Ibn Rushd was broadly cultured indeed and wrote on many different subjects. Here we can mention only the most famous of his great works. In jurisprudence, as noted above, he wrote Bidayat al-mujtahid wa nihayat al-muqtasid (The reference for the searcher and the resort for the fair). In philosophy, he wrote Tahafut al-tahafut (refutation of the refutation), his response to Imam al-Ghazali’s famous Tahafut al-falsafa (refutation of philosophy). Ibn Rushd combined both philosophy and religion in mainly two books: Fasl al-maqal wa taqrib ma bayna l-shari‘a wa l-hikma min al-ittisal (an authoritative treatise on the convergence between the religious law and philosophy), and Kitab al-kashf ‘an manahij al-adilla fi ‘aqa’id al-milla wa ta‘rif ma waqa‘a fiha bi hasb al-ta‘wil min al-subah al-muzayyifa wa 1-bida‘ al-mudilla (an exposition of the methodology of demonstrating the creeds and description of the confusions and innovations in interpretation which confound truth and lead to error). In medicine, Ibn Rushd wrote the Kitab al-kulliyyat fi al-tibb (a general reference on medicine) which was translated into Latin and Hebrew and European vernaculars. It was a major reference in medicine though it never reached the standard of al-Qanun fi al-Tibb of Ibn Sina (Avicenna, d. 1037) which was used everywhere as simply T he Canon of Medicine.

Ibn Rushd had prepared this book especially for practising physicians and students of medicine. He apologised for the work’s brevity, a limitation he attributed to his preoccupation with commitments to judging, political affairs and philosophy. He advised those who sought greater detail to consult al-Taysir (The simplification) of Abu Marwan ‘Abd Al-Malik ibn Zuhr. Al-Kulliyyat is organized under seven broad headings or chapters:

1. Anatomy
2. The function of the organs
3. Diseases (pathology)
4. Syndromes: a brief clinical review
5. Health care, especially sports, massage and sleep
6. Medication and diet
7. Healing (particularly of different types of fevers).

The chapter on anatomy in al-Kulliyat

Ibn Rushd criticized the physicians and students of medicine of his time for neglecting anatomy. His own presentation of the subject is both concise and precise. He divides it into two major areas:

a. Anatomy of ‘simple’ organs such as bones, flesh, and veins.

b. Anatomy of ‘compound’ organs-for example, the arm which comprises bones, flesh, veins, tendons, nerves etc.

His description starts with the bones of the head and the teeth. 

Bones

There are six bones in the cranium and 14 in the upper jaw (the maxilla) and the ear, and two in the lower jaw (the mandible). All these bones are attached by seams except the two bones of the mandible that are articulately joined. This was later established as untrue-the mandible in fact has a single bone not two. The first to discover this was the physician and linguist ‘Abd al-Latif al-Baghdadi (Ibn al-Labbad). He examined 10,000 cadavers removed from the hills of al-Muqattam, east of Cairo, during the construction of a road. He realized this fact after observing thousands of examples. This was revealed in his wonderful book al-Ifada wa l-i’tibar fi l-umur al-mushahada wa l-ahwal al-mu‘ayana fi ardi Misr, (review and lessons from examinations and experiences in Egypt).

Ibn Rushd wrote of the teeth that there are 16 in each jaw-two central incisors, two lateral incisors and two canines, and five molars and premolars on both right and left sides. There are three or four roots in the maxilla but only two in the mandible, the remaining teeth have only one root.

He also described the large aperture in the back part of the skull, the foramen magnum, and its relation with the seven vertebra of the neck (cervical vertebrae), which have apertures on the sides. The vertebrae of the chest region are twelve; in the lumbar there are five, linked to the sacrum in which he counted three bones (in fact there are five) attached to the bone of the coccyx which is also composed of three attached vertebrae.

Ibn Rushd said that all vertebrae are articulate except the first two from the neck, because the first vertebra is attached to two appendices ramified from the skull.

He also said the bone of the sacrum is attached from the sides of the hips, in each of which is the acetabulum (socket) which contains the ‘head’ of the thigh bone (femur), often referred to as the ‘pomegranate’.

Ibn Rushd described in detail the bones of the front side starting from the clavicles up to the pubic bone, passing by the ribs and the bones of the shoulders. He also described the upper and lower limbs very precisely. What he wrote is not different from what we know today except that, for the bones of the arm, he uses ‘lower’ and ‘upper’ zanad (forearm) to mean the radius and the ulna. He indicated the bones of the leg, nowadays known as the fibula and tibia, in the same terms.

Veins and arteries

In the old days, the arteries were called the ‘beating veins’ (dhawarib ), and jugular veins were the ‘non-beating’ veins (ghayr al-dhawarib ). Ibn Rushd made a precise distinction between the two types of veins which remains accurate and valid. He wrote:‘Arteries come out of the heart whereas the jugular veins come back to it.’ He also described the difference precisely, the arteries are more solid and have two similar layers: the fibres of the inner layer are crosswise while the outer layer fibres are length-ways-even by modern standards a very professional anatomical description.

Two arteries of different size come out of the heart, the smaller one goes to the lungs and ramifies into them (pulmonary artery). The other (aorta) is larger, divided into many sections and ramifies into the whole body, one section going up to the head and upper limbs, another going alongside the vertebral column with branches leading to the chest and abdomen; it ends in the lower body and feeds the two lower limbs.

Ibn Rushd’s fascinating description is confirmed as correct and accurate. However, he failed to observe the circulation of the blood accurately. This was not properly described until nearly a hundred years later by Ibn al-Nafis (d. 1288) a Damascus-born physician who worked in hospitals in Cairo, and many centuries before William Harvey (1578-1657). 

The nervous system

The nervous system is the most complicated organ in the human body and its anatomy has only gradually become known over recent centuries. Nevertheless, Ibn Rushd was able to describe the brain, its membranes and the cranial nerves. He describes the smelling nerve perfectly, pointing out that it ends with a nipple like that of the breast. He does not consider this nerve as the primary one, giving that distinction to the optical nerve. The first pair of nerves issue from the brain and form the sclera inside the cranium, then come out to the eyes each from its side. This is a wonderfully precise description.

Ibn Rushd then describes the nerves that feed the muscles of the eye. According to modern anatomy, these nerves are the third, fourth and sixth, but Ibn Rushd considers them all as the second pair that ramifies in the muscles of the eyes. He considers the third pair as related to the next (the fourth), and these feed areas of the face, the ear, the palate and the nose-in fact, he was writing about the fifth and seventh pair of nerves according to modern anatomy. As for the fifth, Ibn Rushd says that a part of it leads to the ears and the muscles of the cheeks, whereas this is identified as part of the seventh pair.

Ibn Rushd writes that the sixth nerve feeds the pharynx and the tongue and part of it leads to the muscles near and around the shoulder and another part deviates to the neck and a branch of that goes to the larynx. This is actually the eleventh nerve (the accessory nerve) and there is some confusion in Ibn Rushd’s account with the description of the tenth nerve (vagus; the wandering or confused nerve). Although he attributes many characteristics of the vagus nerve to the accessory one, Ibn Rushd is very accurate in the description of the characteristics themselves. He observes that some of the branches of this nerve lead to the chest and feed the heart, lungs, and esophagus; that it runs through the diaphragm and makes the link with the cardiac and liver membranes, the spleen and the rest of the intestines/bowels.

Ibn Rushd describes the seventh nerve as starting from the back of the brain and ramified in the tongue: he is describing accurately the twelfth nerve (hypo-glossal).

He describes as accurately as modern anatomy does, the nerves that go along the vertebrae. He mentions the eight pairs of cervical nerves, sixteen pairs of dorsal nerves, and five pairs of lumbar nerves.

He misses the correct number of the sacral nerves, they seemed only three to him because they are very closely attached-in fact they are five. Three nerves come from the bone of the coccyx and a single nerve comes out on the sides from the middle. This is absolutely accurate.

Ibn Rushd wrote;

‘The brain has two nipple-shaped appendices that grow from its two advanced abdomens (olfactory bulb). They reach the bone that resembles the cribrium (cribriform plate), which is perforated with many holes [i.e. like a sieve], not smooth but rough with its position in the cranium, where it reaches the end of the nose.’

It would be very hard to improve on the concision or accuracy of this account even today.

About the membranes of the brain, he wrote, again with wonderful, inspiring accuracy:

The brain has two membranes, one is hard and thick (dura mater), and the other is thin (pia mater), they cover the brain very closely and in some locations are completely joined. The thick one is adherent to the cranium. This membrane has many perforations in two places, the first at the canal at the end of the nose (cribriform plate), and the second at the bone of the palate. Under the brain on the thick cover, there is the mysterious net composed of veins that go up to the head.’

The structure of eye

Ibn Rushd’s ability and competence as an anatomist is most clearly demonstrated in his description of the eye and its layers, which compares most favorably with what is known today except some minor differences in terminology. Ibn Rushd had even established the original development of the layers of the eye in the fetus, and discovered that they appear to imitate the layers of the brain and its membranes. Ibn Rushd combined accurate observation with brilliant exposition, sight with insight, presenting the structures of the eye as well as any twentieth-century expert could, and did so many centuries ahead of any physician in Europe.

He wrote:

The eye is composed of seven layers and three liquid areas. The first, from the side of the cranium, is a membranous layer that develops from the thick layer (sclera). The next layer from outside develops from the thinner membrane of the brain; it is called al-mashima (choroid). The next is a layer similar to the net (retina). It grows from the same nerve that comes out of the brain. In the middle of this layer, there is a soft and liquid area called al-rutuba al-zujajiyya (vitreous humour). Inside it, there is another spherical body but with some minor flatness. It is as clear as the ice and called al-rutuba al-jalidiyya , and we call it nowadays al- ‘adasa (lens).’

Ibn Rushd continues this wonderful description, by mentioning al-rutuba al-ma’iyya al-amamiyya (aqueous humour), he also called it al-rutuba al-baydhiyya because its liquid is similar to the soft liquid egg-white:

‘On the outside of this liquid appears a soft body whose inner texture is velvet-like, that follows the al-rutuba of baydhiyya (aqueous humour); smooth from the outside its colour is different from the body of the other, it can be very black or less dark or even blue.’ This is an extremely precise description of the iris (quzahiyyatu al-‘ayn) and the ciliary body (al-jism al-hudhabi).

He adds:

‘Inside the ciliary body, next to the lens, a hole that widens and narrows depending on the extent of darkness that it needs, the hole is called hadaqa (pupil) and the membrane itself is called the inabiyya (grape- like) layer.

‘Next to this layer, a cover that has a hard and clear white and thin plate which is called al-qarniyya (cornea). It takes the colour of the layer below it. On the top of this rises a white body called al-multahim (conjunctiva).’

Ibn Rushd also wrote about the physiology of sight:

‘The sight is not a thing that comes out of the eye as Galinius used to think. The eye receives the colours through the reflecting objects in which they are held, in the same way as a mirror does. Once the colours are reflected in the eye, the object is then conceived by the visioning power.

‘This could well be proved in natural science (physics). That is why any of those parts of the eye is able to reflect the colours because of its very glossy surface. So that body is the special tool to the lens and the advantage of the qarniyya (cornea) is . . . [that] it is made clear and thin so that it does not prevent the ice-like liquid (lens) from receiving the images.’

This is an accurate description of the eye and the physiology of sight that does not differ much from what we know today.

From this brief dip into a chapter of al-Kulliyyat fi al-Tibb , we realize the importance of the work of Ibn Rushd-jurist, philosopher, physician. He was an expert in each of these fields and the most distinguished scholar in Spain and North Africa. He neither experienced nor discovered any contradiction between his religion and his science; rather, his quest for knowledge and excellence, his wonderful curiosity, enlightened and improved his faith. His famous observation- who practises autopsy, his faith in God increases -should silence the false allegation that Muslims never practised anatomy and that they are against applied sciences. What has been written by so many Muslims in all fields of knowledge refutes this allegations. Medicine and the other applied sciences are a necessary and essential contribution to the well-being of humankind. Therefore, to work in them is fard kifaya , a collective obligation upon the community of Muslims as a whole, an obligation which some members of the community must undertake on behalf of the others who cannot.

Islam is the guide for those who seek true and sound knowledge in every subject. All sciences, so long as they are directed to God and not to merely worldly ends or personal glory, bring their students closer to God and make easier the way to approach and please Him: Those who fear God, amongst his servants, are those who have knowledge. And God is the Guide to the straight path.