Amyotrophic Lateral Sclerosis (ALS) is a terminal illness of the nervous system, resulting in the degeneration of neurons. When the motor neurons in the lateral spinal cord degenerate, the muscle cannot be stimulated and gradually atrophies. As the disease progresses, the brain cannot initiate and control muscle movement, so voluntary muscle actions, such as reaching for your phone or typing on a keyboard, are lost. Currently there are no treatments or cures to reverse the effects of ALS and the disease process is still widely unknown. Some noteworthy individuals diagnosed with this disease have included Lou Gehrig, Stephen Hawking, Jon Stone, George Yardley, Henry A. Wallace, and Steve Gleason. These are the facts, but I could have never realized what living with ALS was like until I listened to a retired senior, a teacher, and a musician tell me their stories.

The older couple told us of their past year as the husband wrote on an electronic note pad to fill in the gaps of his spouse’s version of their story. They had first noticed his symptoms when he began choking on his food, and they had to adapt as the disease progression got more and more severe. His wife comically said that she doesn’t know where to look when he’s trying to talk to her – “Should I look at his eyes, his mouth, this pad?” Every day, they had to face a new challenge and overcome it together, as a family.

Another patient was a mother, a teacher, now wheelchair bound and with a respirator to help her breathe. Because of her age, none of her physicians expected ALS and thought she was struggling from carpal tunnel syndrome or an ulnar nerve injury. She told us her husband was her biggest caregiver and supporter; her husband joked, “She makes the list and I carry it out.” He talked about his struggles, working full time as well as being a full-time caregiver for his wife and their 3-year-old daughter, as well as still finding time for self-care. Even with all this juggling, he felt guilty. This guilt was expressed by many of the caregivers: some because they didn’t even notice the symptoms and others because they felt like they couldn’t help their spouses. Guilt was felt by the patients too. The mother was upset because her daughter would only remember her in a wheelchair. Despite the difficulties, family was a major support system for each patient.

When asked about how she felt after getting her diagnosis, the musician said, “I felt like a deer in headlights… I never pictured I was going to go out that way… with a terminal illness… Last year I had no trouble walking, singing, cooking, gardening, and this year…” Despite all of this, she said she felt relieved. Her struggle to find a neurologist who respected her was heartbreaking. She had gone to a physician because she felt helpless; she was having trouble playing guitar, she was losing her identity as a musician. However, the physician assumed from her past medical history of anxiety that she was having mental issues with memory, anxiety, and depression. As she continued to receive hostile treatment, she found a second doctor who listened to her. Unfortunately, even though he took her seriously, he didn’t have the courage to diagnose her with ALS, telling her instead that she had a motor neuron disease and referring her to a specialist. When she finally received the diagnosis of ALS, she was relieved. She no longer felt crazy. She was able to be heard. She was able to communicate with someone who wanted to help her. ALS is already a hard disease to diagnose; not having someone on her side only made her situation more difficult. She says now, as each symptom appears, she isn’t afraid anymore, because she knows it’s ALS. This relief of having a concrete diagnosis, of having a diagnosable disease, even one that is untreatable, was reiterated by several of the other panelists.

Although a diagnosis was a relief for many of the patients, they all saw the importance of taking part in clinical trials. They recognized that ALS affects everyone at different times in different ways and hoped that one day they could explain why this illness is so hard to detect and track. Participating in various studies and trials made them feel like they were helping future patients and physicians to be able to better understand why this terminal disease can strike at any time, with no discernable warning signs, affecting each individual uniquely in initial symptoms and progression.

Getting a concrete diagnosis gave these patients the freedom to seize the day and live in the moment. For the musician, as her ability to play guitar diminished chord by chord, and she started slurring her words, preserving her voice and her identity became very important to her. She is using a message banking app to preserve her voice. The software requires her to read thousands of words and sentences. Although she had to accept the things she could no longer do, she realized that she did not have to give up her identity or love of music because of ALS. Overflowing with her love of music, she told us about how when choirs sings together, their hearts become synchronized; and how music lowers blood pressure and stimulates all areas of the brain. As she interwove details about her symptoms with her favorite song, Fire on the Mountain by the Grateful Dead, the two had become part of the same spiritual transformation. Smiling peacefully, she explained, “Maybe nobody else hears it the way I do. I see death as the final healing, finally being released from your body.” She viewed her diagnosis as graduating early and the symptoms that came attached with it as her disappearing slowly, rather than all at once. The unavoidable indignities were just something she had to accept. What mattered most to her was keeping her individual personality in the face of intense daily struggles.

By the end of our discussion, I felt the weight of my white coat as I never had before and recognized that this would be the first of many times that I would have to carry this symbol of patient advocacy. As these patients spilled all their vulnerabilities to a group of 50 students, I realized the most important thing I will learn in medical school is opening my heart without getting crushed under negativity. I learned that, as doctors, we have the tendency to think the ultimate solution is life, when in truth, mortality is the reality. What matters is being present when there is a fire, realizing that “a pail of water” may not be enough to put it out, but continuing to carry that water for your patient.

Long distance runner, what you standin there for?
Get up, get out, get out of the door

There’s a dragon with matches that’s loose on the town
Takes a whole pail of water just to cool him down
-The Grateful Dead

The heart is composed of four compartments: two atriums and two ventricles. The blood that reaches the heart first accumulates in the atriums. From here, it is sent to the ventricles. Afterwards, it is redistributed to the body by the contractions of the ventricles. The harmony of this process depends on the electrical currents in our hearts.

How is the electrical current formed?

There is a particular region in the heart called the sinus node. The sinus node is strip of a muscle that is 15 mm in length, 3 mm in width, and 1 mm in thickness, and is located in the right atrium of the heart. The cells of this strip are responsible for producing electrical currents, and are created in a different fashion from the rest of the cells that are responsible for producing contractions. This is where the electrical currents in our hearts are periodically produced. Every cell in the body contains elements such as sodium, calcium, potassium and chlorine that are electrically charged. The elements which are electrically charged are called ions. These ions also exist in the extracellular environment. The intra cellular and extra cellular concentrations of these ions are different from each other. This situation causes a difference in the electrical potential between the interior and exterior of a cell. This difference is called a membrane potential. Periodically, the membrane potentials of the sinus cells show sudden jumps – meaning they suddenly increase and then suddenly decrease. Since the cells are in close contact with each other, such a jump in the membrane potential of one cell triggers a jump in the membrane potential of another cell. The electrical currency that enables the contraction of the heart is produced by this continuous triggering of cells. On average, 70 electrical currents per minute are produced in the sinus node. These currents start being produced while a person is in the womb of their mother and continues their whole lifetime. The heart of an embryo starts beating while it is only 22 days old. However, the height of the embryo at this point has not even reached 1 cm. Isn’t it an amazing force that creates the beating heart of such a small embryo and keeps it going a lifetime?

How is the electrical current distributed?

Another node called the atrio ventricular node was created in between the atriums and ventricles in our heart. While the current coming from the sinus node is spread to the whole of the atrium, it is by this node that the current is sent to particular fibers. The task of this node is to hang on to the current coming from the sinus node for a while. Why does the current need to be held on to? Because blood can only enter the ventricles while it is resting and by holding on to it, the contraction of the ventricles is disabled while the contraction of the atriums is taking place. By this process, the blood coming from the atrium can enter the ventricle. Therefore, the blood fills in the ventricles and can be distributed throughout the body. The blood circulation is enabled in a flawless manner by allowing the atriums to do their duty while the ventricles wait.

After passing through the atrio ventricular node, the electrical currency eventually goes through the purkinje fibers. These fibers surround the ventricles like a web and are composed of cells that can conduct electrical current in a very fast manner. Compared to the atrio ventricular node, the electrical current can be conducted 150 times faster in the purkinje fibers. Therefore, the current reaches every point of the ventricles in a very short period of time. Every muscle in the ventricles contracts in a time shorter than one tenth of a second.

The muscles in the ventricles rapidly contract, one by one, depending on when the current reaches them. The contraction starts at the end of the ventricles and carries on towards the main veins exiting the heart. By this orderly and harmonious contraction, the blood is pumped from the end of the heart towards the main veins exiting the heart to be distributed among the body. Because all the ventricle muscles are stimulated very fast, the contraction also happens very fast, resulting in a strong pumping effect. The design of this system is incredibly wise, right down to its most minute detail.

Movement in heart muscle potential

As all cells in our body, the cells in the heart also have a membrane potential. We had stated before that this membrane potential is the result of the difference in intra and extra cellular ion concentrations. The charges of these ions are different from each other. For example, sodium and potassium have plus one (+1) charges, calcium has a plus two (+2) charge, and chlorine has a negative one (-1) charge. The resting potential of a cell is negative. This means that there are more negative ions within the cell when compared to its environment. Sodium, calcium, and potassium ions are mobile through the membrane. While sodium and calcium have a higher concentration outside the cell, potassium has a higher intra cellular concentration compared to its environment. There are channels created on the cell membrane that allow ions to pass through the membrane. The sudden increase in the membrane potential that was explained before causes a sudden rush of sodium ions inside the cell. This is such a rapid movement that it is concluded in a tenth of a second. Right after the entrance of the sodium ions, calcium ions also enter. Because these ions are positively charged, the membrane potential becomes positive.

With the entering of calcium ions into the cell, calcium ions are also released from the storages within the cell. By triggering the protein necessary for these contractions, the calcium ions become a means for the contraction of the heart muscles. Meanwhile, the potassium channels open and these ions within the cell pass to the extra cellular environment. The loss of positive ions results in the membrane potential being negative again. Therefore, the sudden jump in membrane potential that is the basis for the electrical current is created.

However, at this point there are extra amounts sodium and calcium within the cell and extra amounts of potassium outside the cell. The concentrations need to be returned to their original values for the next jump in the membrane to be possible. This task is given to a protein called the sodium-potassium pump that pumps out sodium from the cell and pumps in potassium. If this pump had not been created, the ion balance in any of the cells within the body would be impossible to re-establish. As a result, the life of the cells would come to an end. However, because of the remarkable intricacy of our cells, life is made possible for us.

Afterwards, some amount of the calcium ions are pumped out of the cell with a similar pump, while the rest are stored within the cell. The decrease in the concentration of calcium relaxes the muscle. Now the heart muscle has gone into relaxation and therefore is ready for the next contraction.

If the movement of the ions becomes unbalanced, the rhythm of our heart is disturbed. The unbalance in the ion movements or blockage in heart veins can be reasons for heart rhythm disorders. Even small heredity-based defects in the ions pumps affect the movement of these ions and can cause heart rhythm disorders. This situation shows that nothing is created by coincidence.

Movement in the sinus node

The jump in the membrane potential of a heart cell depends on the membrane potential jump of the previous cell. Through the gaps in between the cells that are in contact with each other, the positive ions that exit a cell reach the membrane of the cell next to it and trigger the opening of its ion pumps. As a result, the membrane potential of that cell starts changing. At this point, you may have this question: how does the electrical current start in one end of the sinus node that is not previously triggered by any cell?

This concept is explained by the ion transfer mechanism of the node cells being different than the muscle cells. Before explaining this, it should be noted that even while resting, a mechanism for allowing an ion exchange of the cell with its surrounding has been created. In the node cells, this exchange while at rest has been created in a way that the sodium and calcium exchange is larger and the potassium exchange is lower compared to the muscle cells during resting conditions. Therefore, the membrane potential of the node cells is less negative and slowly increases with time. As a result of this slow but steady increase, after a while it reaches a threshold. When it reaches it, the calcium channels in the membrane suddenly open and there is a rush of calcium ions into the cell. Thus, the jump in the membrane potential is created independently from another cell.

As it can be observed, even a single contraction of our heart depends on a very detailed, delicate, and complex system. Moreover, this system is repeated over a hundred thousand times within one day. After reflecting on this, how can we claim this system runs by coincidence or chance?

How good are we aware of the operations of systems and mechanisms that make us walk?

Costly research and development efforts are under way in centers throughout the world seeking to build walking robots by mimicking human mobility. After 14 years of research, automotive firms built Asimo, a robot which can walk bipedally and climb stairs like humans. Even though the moves Asimo could make matched those of a one year old baby, it was still considered a great success for the robot technology.

Hardships encountered during these research projects proved walking to be a great miracle, apart from normal habits of movement. We often become aware of how extraordinary movement is and that the moves we repeat hundreds of times, such as walking, running, bending, sitting and standing, are blessings granted to us only when we see someone who has lost some of their mobility.

That humans can walk bi-pedally is truly exceptional. Most organisms have a front leaning skeletal structure and walk on four extremities; they only stand upright when absolutely required to, since it is very difficult for them. Human ability to stand upright and walk on two legs truly signifies them as special amongst creatures, and sets them apart from all of creation. The lively, regal posture of dexterous bipedal humans constitutes very important evidence showing they are “the most superior of all creatures.”

The multifunctional, flexible nature of our skeletal system enables us to complete very simple moves automatically. Walking seems to be a very easy task, however, it occurs as a calculated outcome of many factors, such as determination of stepping distance, the toning of corresponding muscles of the same and opposite direction, relaxation and contraction levels, and relocation of the body’s gravity center.

Walking takes place via the coordinated works of the locomotor (musculoskeletal) system, motor control system, and balance-coordination system.

Locomotor (musculoskeletal) system

The framework of the human body is built together with 206 bones of variable hardness. With their strong nature and capacity to endure extra weights, bones takes up 20% of a body’s mass, and are the major load bearing part of the body’s structure.

The main part of our skeleton is the vertebral column. It consists of 33 small bones, known as vertebrae, positioned on top of each other. Wear-preventing discs are found in between vertebrae to protect against motion related wearing over time. As the vertebral column holds the weight of the upper body, it is created in a way to keep the body upright. The spinal cord inside the channel that is surrounded by the vertebral column is a very important signaling network providing coordination between the brain and other organs.

Joints and ligaments are among the moving parts of our body. The most important joints for walking are the hips, knees, and ankles. The curvy shape of the foot and its contact to the ground at three spots supports bones against body weight and helps with balance. This is why flat footed people struggle with walking and get tired easily. The curves of our spine at the neck, back and waist regions, and the hips, knee joints, and curvature of the foot, are perfectly shaped for standing upright and walking.

In order to move we need a muscle system along with the skeletal system. Muscles are made up of thousands of contractible muscle fibers. There are more than 6 billion muscle fiber motors in the human body. We walk, run, eat, breathe, talk and do many more moves by using ability granted to muscles. Approximately 35 muscles in each leg, and around 100 muscles in the whole body, function during walking.

Ligaments and tendons are links that secure bones and muscles together; they also help to stabilize joints, thus when standing, joints remain in place without muscles contracting.

Four different mechanisms are involved in walking:

1. Proper upright posture and maintenance of balance during walking
2. Forward motion of body via muscle power
3. Reduction of shock-impact effect while stepping
4. Maintenance of motion with the least amount of energy.

A series of movements is generated in the legs to provide a forward motion and these are constantly repeated. These constant repetitions are called the “walk cycle.” The “passing pose” is defined as the time frame when the leg is in the air, and the contact pose is the phase during ground contact. In the middle of the contact pose, even though body is in balance, because of the forward momentum of the body, balance is lost, thus the body leans forward. Balance is then restored by stepping on the ground with the leg in the air. As a result of this rhythmic loss and restoration of balance, the body moves forward.

In a person standing upright, the center of gravity is in front of the fifth vertebra. At the start of a walk, the body leans forward to carry the center of gravity towards the front; then the initiation of the motion via forward transfer of the power with toes and joints takes place, followed by the lifting of the heels, the bending of the knees, and the lifting of the foot, thus displacing the center of gravity of the forward leaning body towards the front.

Balance should be maintained when one leg is lifted in order to let the other leg carry the load of the body’s weight. The gravitational center of the body is located in the distance between the two legs since each leg is located on the side. Body balance is maintained by the contractions of dorsal muscles located across the side of the stepping foot, working in parallel to support and transfer body weight to the foot via the hip and femoral muscles. These events happen so quickly that we often do not even notice all the complicated processes.

The great Sufi figure Abdul-Qadir Gilani was often asked questions such as, “Master, show us a miracle.” He would stand up to walk three to five steps and sit back down. Everybody was confused, looking at each other. One person among them was heard saying, “Master, excuse us but we can all do that as well.” Gilani replied then, “Is there a greater miracle than walking? You see it, but do not understand.”

Motor control of walking

Bodily motions are controlled via the primary motor centers that are located on the side and cortex region of the brain. These centers are created in a way to prepare and organize motor programs involving body movements, and to integrate them with the proprioceptive memory. This synthesis of information enables the adaptation of motor commands to the present posture of the legs and arms regarding intended moves.

A desire to make a move is a necessary prerequisite for the stimulation of muscles pertaining to it. If we want to hold something, we can easily do it; when we want to raise our arm, our elbows bend; to run or walk, our leg muscles start to move and work. How do all of those moves happen? Is our desire enough to do so? Can the guidance of all the bones and muscles, working together towards the same target, happen by itself or occur via coincidences?

In order for muscles to move, our thoughts must be relayed to them and this is provided by the nervous system and nerve network. There is an amazing communication network present in our body. In case of an intended move, an electric signal is sent by the brain. During this journey, which seems to be complicated, the signal arrives at the spinal cord and then quickly diverts to the corresponding organ. Millions of motors that make up the muscle are stimulated by the electric signal, contracting the fibers instantly upon reception of the signal. In order to do a coordinated move, it is necessary to know the related body organs’ positions and their relations to each other. Millions of transmitters that provide this information have been placed throughout the body. This data come from the eyes, the inner ear’s balance and sensory organs, muscles, joints, and skin. There are billions of micro receptors located in muscles and joints programmed to send instantaneous positions of the body to the central nervous system. In every stage of a move, the positions of the muscles are reported instantly to the command center by these micro receptors inside the muscles. New commands are given to the muscles based on the assessments made here. This way, each second, billions of bits of information can be processed and assessed.

The cerebellum is another center that is in charge of functions such as maintenance of balance during walking and standing, carrying out proper and coordinated moves with visual control, providing coordination among muscle groups, promptly starting and stopping movements, and the maintenance and organization of normal muscle toning. The cerebellum is tasked primarily with hastened muscle activities like running, typing, and talking. Thus, fast moves necessary for the balance system are sustained properly and successively without abnormal oscillations.

Specific motion templates have been programmed in the spinal cord for all muscle-covered regions of the body. Rhythmic movements, such as forward and backward motion of the legs and arms, and coordinated activities of other body parts in tandem with walking, are controlled here. The task to control repeated moves like walking is assigned to the nerve network consisting of the spinal cord, brainstem and cerebellum.

Balance and coordination system

One of the requirements to walk and move is to stay in balance. Despite our advanced musculoskeletal system, without balance, this system of ours would be useless, or even dangerous.. Our balance system, which is in charge of the instantaneous control and fine adjustments regarding our body, is granted to us as a blessing of Divine compassion.

There are three systems that provide data involving the positions of the head and body: vestibular system (the apparatus of the inner ear), visual senses, proprioceptive senses

The vestibular structures are an essential part of the balance system. They are found in the inner ear, and are small and complicated systems. This 6.5 mm diameter wide system is composed of semicircular channels that contain specific fluid and ciliated sensory cells that cover the inner linings of the channels. This system constantly reports information involving our status in the outer world and instantaneous changes to the balance system.

When we move, the fluid inside the semicircular inner ear channels get displaced; this motion vibrates the cilia. This vibration causes an electric signal to generate in the cells. This electrical signal is then transmitted to the cerebellum; received information gets evaluated instantly in the cerebellum. This system is created to function autonomously without our will and control. When this system is impaired, balance disorders occur, such as dizziness.

Information regarding our position in the environment and the relative status of the environment according to us is sent to the cerebellum and brainstem via our visual senses.

Proprioceptive senses are formed via the activities of tension receptors built in muscle fibers, tendons and joint capsules. These are sensitive to motions and positions. These receptors regularly provide information to the central nervous system. The cerebellum receives information from all the muscles and joints of the body, including the eyes. These inputs are analyzed very promptly at the cerebellum, and the relative gravitational position of the body is finely calculated, thus the proper motions of muscles are determined. The resulting response is relayed towards muscles by nerves. These events take place in a time frame that does not even last for a hundredth of a second. We easily walk, run, and do complicated moves without feeling any of these activities happening inside us. Yet the calculations taking place in our body even for a single moment of those movements can fill thousands of pages.

To understand the fascinating side of our ordinary movements, let’s consider a person climbing up the stairs. First, the eyes scan the surroundings, then the three dimensional information of positions acquired from the materials and belongings in the environment are transmitted to the brain. Once received, the information is analyzed and the necessary commands are sent to the target organ from the motor centers of the brain. Commands passing through related tracks and centers finally arrive at the musculoskeletal system. Many factors, like the height of stair steps, length and depth of the foot step, center of gravity and position of the body, are calculated and determined almost instantly.

Proprioceptive signals constantly report the positions of organs, like the arms and legs, to the command center. Inner ear receptors are in charge of the prompt transmission of information necessary for balance, like motion, speed, and direction of the body. These inputs are calculated in milliseconds at corresponding centers in order to maintain the coordination and harmony of the entire body. A person who is running up the stairs may think to jump a couple of stairs. This change of command is rerouted to the locomotor system as a new and different command from the brain. All of these processes are completed in centiseconds. In the mean time, the head, shoulders, and arms are employed for rhythmic oscillations in order to adapt to the overall body momentum.

In conclusion, standing and walking are miraculous and take place via thousands of interrelated activities. Nonetheless, we usually do not notice any of the thousands of processes that are constantly taking place. One hopes that every blessing we have is seen through the window of thanksgiving and appreciation.

Kemal Serce is a professor of veterinary medicine in Bursa, Turkey.

“There are numerous perfect mechanisms put to work by our Creator in a fashion that is impossible for us to know; it is equally impossible for us to control each of them.”

“This body is mine! Thus, I have a right to use it as I like!”

How do we own our body? How much of it belongs to us? Can we still stand behind the phrase “this body is mine!” when we explain “scientifically” that it is not? To what extent does that statement meet the truth?

First paragraphs of human biology textbooks strongly mention the phenomenon that the sustenance of life takes place outside our will. Does our first creation in our mother’s womb, when we become existent out of nowhere, happen by our will? Do we have a say in the creation of our body, which is the dress of our soul? Of course we don’t. Even our senses, which are involved in eating and drinking, exist outside of our will. The feeling of hunger, for instance, does not come forth from our control; it is dependent on the emptiness of the stomach, and low blood sugar. Hunger is not only a sense of alarm or warning, but also a feeling that forces one to eat; it disappears when one is full. If it was only a sense of alarm, one could get away with it. This situation shows that the human is not a machine composed of flesh only. If we refuse to respond to this feeling of hunger, it may eventually lead to serious, even fatal, consequences, such as patients suffering from Anorexia nervosa, a severe psychological disorder that can lead to self starvation.

If there were no such thing as hunger or appetite, humans would not be interested in working. The feeling of hunger is a remembrance to the One who provides. As a matter of fact, all our emotions are temporary belongings that provide for the sustenance of life, and for the continuation of generations. Sexual desires are provided so that we can have families and can continue the human race; an appetite for food is given so that we can maintain our lives, and the sense of cold is given so that we dress.

In our village, one of our neighbors suffered from a stroke. All of the senses of pain, hot or cold, and touch disappeared from his legs. A pathological sense urged the patient to ask care takers to warm the stroked leg. Upon the patient’s strong request, care takers tried to warm the underside of the foot with a hot iron over a piece of cloth. As a result, the patient suffered severe foot burns all the way to the bone, since neither the patient nor the care takers noticed the damage. The nerve endings embedded in our skin are in charge of sensing hot or cold; and nerves that are buried deep in our legs and arms are tasked with relaying those senses to our brain.

Despite feelings of cold or excess heat being connected to certain areas of the brain and nerve cells, these senses are not completely delivered to brain. That is to say that we are not simply machines made out of elements found in the earth. We do have emotions and a soul in charge of controlling those emotions, and a spiritual world connected to it. It is such that even senses of hot and cold do not belong to us and we cannot even generate or control them.

We cannot start our body just like we start a washing machine. We do not have a button to restart our heart in case it stops. How does a heart work? Have we ever thought about the number of nerves employed in sympathetic and parasympathetic autonomous nerve networks that make the heart work? All of the muscle cells of the heart contract with perfect timing. Do you know that special channels called “gap junctions” in between neighbor muscle cells are put to work wondrously in order to let electric signals pass from one cell to another? If millions of muscle cells in a heart did not have to work like that, how could all our cells get their nourishment, necessary substances, and oxygen in time? All of these processes happen outside our will.

How many red blood cells or white blood cells do you have, and how are they working? When the hemoglobin molecule reaches cells, it releases the oxygen molecule that is bound in lungs. Does the hemoglobin do this act of binding and releasing by its own discretion? Red blood cells get accelerated with proper speed so that cells get their nourishment on time. Is this something we do on our own? Our body is protected from diseases as white blood cells recognize and attack foreign microorganisms and substances. How can a white blood cell separate normal cells from harmful bacteria? There are numerous perfect mechanisms put to work by our Creator in a fashion that is impossible for us to know; it is equally impossible for us to control each of them. We do profit-loss calculations in every business of ours. Our body employs a great principle of economy; do we know how that is put to life or who makes that work?

Neurons, axons, dendrites, synapses, and neuro-transmitters exist and function in amazing numbers in our brains. Countless connections between neurons, and electric currents through synapses, happen without us even noticing them. How do neurotransmitters only bind with their own receptors and open ion channels? How does this relay of information occur in our brain when Na and Ca ions, existing in soil, rocks, and salt – which we use as a condiment – pass through these electrically controlled ion channels? Even if we know about these intricate works, it is still not up to our will to enable or control them.

How do nerve networks function? How many types of neuron circuitries exist, and how do they work? How does membrane potential form in nerve and muscle cells? How is action potential generated? When we touch a substance, which nerve tracks are utilized to transport the information? Do we have the option to pull the plug of pain and feel free of it? If this machine-like body belonged to us, then we could control and regulate it.

When we are purchasing a computer, we get the hardware according to our budget. We ask and order for the processing speed, memory, and the capacity of a computer to meet our needs. Do we get to arrange the capacity of our brain that we think we own?

Do we know that more than 75% of chewing is a reflex and happens outside our control and will? How good is it that we realize that only one of the three phases of swallowing is actually under our control and the rest of the process happens by our reflexes during eating and drinking? If swallowing was to be in our control, it would be highly likely that pieces of food and fluid droplets would easily choke our lungs and might cause death. How do our stomach and intestines work? At what speeds do secretions and movements take place? The content and amount of oral, gastro-intestinal, and pancreatic secretions are regulated according to the amount and type of food we intake. These regulations continue through our lifespan without any cessation.

Are we able to stop our heart beat when we are just a baby in our mother’s womb even for a minute? How does our heart work? How much blood is pumped in a minute? Approximately how long after the conception of egg and sperm does the heart start to beat: weeks, days? Do we know that our heart starts beating when we are as small as a tiny piece of flesh around week four?

How can we assert that we control our body, even when, to this day, scientists do not have a solid comprehension other than some assumptions of the rhythmic continuation of respiration during sleep or coma?

Since we own this heart and lungs, therefore can we manage to die whenever we want to stop them? Never!

We can conclude that the assertion of “this body is ours” is a deceptive, misleading perception. This body is given to us as a temporary belonging. It is very clear scientifically that all of the works, acts, and wondrous arts of the body do not belong to us, but to the One who created them. Our responsibility is to keep that in mind and be thankful for all the bountiful blessings.

Omer Arifagaoglu is a professor of medicine in Turkey.

Distribution and density of the hairs in our body is coded in our genes. This program is activated after birth and hair roots are formed at around 8th-10th week of pregnancy. The hairs that cover the fetus are thin, short, and weak. The growth of hairs is completed in the 22nd week. Number of hairs in a fetus does not change much according to gender. Later on in a person’s life, hairs can become dense or rare, owing to factors such as race, age, gender and hormonal state. There are hair roots covering almost all over our body except for the soles, palms, forehead, the areas under the eyes, on and behind the ears.

A hair is made up of the hair root and the hair shaft on it. A hair root is surrounded with two layers. The duty of these layers is to prevent harm to the hair shaft and let the hair grow in the right direction. A hair root is a multilayered structure where every layer has a different function. The papilla is in the base of the hair root and it basically serves to send nourishment to hair cells. The upper layer of the hair shaft is the hard substance called keratin. The innermost layer, which can be seen as the spinal cord of a hair, does not exist in every hair shaft. The second layer, known as the cortex, constitutes most of the hair shaft. The color of hair is mostly determined by the pigment in this layer. The outermost layer is the upper skin of the hair.

Hairs in different parts of the body have their peculiar forms of and limits to growing. Under the control of hormones, hair roots cause hairs of different properties—such as thickness and color—to form. The hairs in moustache, armpits, between the legs, beard, and on the head grow fast and continually. On the other hand, the hairs on our arms, chest, back, legs and including those in the eyebrows grow very slowly and they know their limits. If the person does not own functional testicles, there may be no hair in certain areas of the body except for the hair on his head.

Most of us are apt to think that certain stories make our hair curl; actually, hair erector muscles are the unsung heroes of those stories. Under every hair in the body, there is an erector muscle that makes it move. These muscles have important functions for the body.

Firstly, it helps the oil glands carry out their function. The oil sacks are located on the surface of a hair. The sizes of these sacks are around 0.2-2 millimeters. Sacks are in the form of clusters. Oil glands are also placed all over the body, accept for the soles and palms. They are the natural “lubricants” for the skin and hairs; they protect the skin from the damage of drying up. Every gland under the skin has a channel. There are alveoli that open to every channel. When the hair muscle is stimulated, the hairs become erect and the connected gland start secreting a substance called sebum. The glands empty their contents to the body of the hair.

Regulating the acidity (pH) level of the skin is among the duties of the hair erector muscle and it produces a protective gel. The oily secretion forms a thin layer of gel; as it serves protecting the skin from heat and cold, it is given an antibacterial effect as well. The natural coating of the skin prevents reproduction of harmful germs. The pH level of the skin is 5-6 and it does not allow bacteria to grow. If this substance is not secreted from the skin, the pH acidity shifts toward alkali, moisture level of the skin increases; the fat layer and then the natural coating is damaged. Thus, germs find a suitable environment to reproduce.

Hair erector muscles are also given a role in adjusting body heat. The hairs in the human body are not related to heat isolation. When the body is exposed to cold environments, the mechanisms that increase body heat are activated. When sympathetic nervous system stimulates hair erector muscles, they contract, hairs bristle, and the body heat is tampered through the reduced heat release. Sometimes, even the invisibly small hairs erect and goose bumps appear on the skin. The purpose is to form a screen for heat. They also allow for perspiration in hot weather and help the body to cool down. In addition, hair erector muscles serve as touching receptors as well. The receptors in hairs easily detect objects on the body surface. Hairs that are activated by touch stimulate the nerve tissue in their base. In a way, they keep a round the clock watch for the body; as tiny and unsung heroes.

They say that perfection is hidden in details, which is also very true for hairs. And perhaps, the secret to appreciation lies in recognizing details, and appreciating their perfection.

Why is this surface area so large? What could the wisdom behind it be? Tiny endoplasmic canals play a role in inner cell transportation and distribution of matter. ER is the organized industry district in the cell. Most of the factories of molecules produced by chemical reactions are found here. ER is the production spot in the cells of proteins and hormones. Consequently, a broad surface area is very necessary and important.

Different degrees (pH) of acid are necessary for each reaction. However, because the acid necessary for one reaction can negatively affect the other reactions, thousands of opposite, intricate and different reactions take place. For this reason, membrane surface areas need to be wide. Sometimes hundreds of protein molecules are produced in just a second in a cell. The rapid and flawless lining up side-by-side of tens, hundreds or thousands of amino acids can only be achieved with a knowledge and power that surpasses these very small structures.

Wrapping the inside of the cell like a web and forming a buffer against mechanical effects, ER is responsible for establishing the flexibility and soundness of the cell. In muscle cells, ER takes the name Sarcoplasmic Reticulum (SR), which has a very important duty in the contraction of muscles. The size of the surface area of SR in the muscles of the structural frame is proportionate to the speed of muscle contraction. Consequently, there is more SR in muscle cells where there is rapid contraction. SR also serves as a calcium depot in muscle cells. Normally calcium is a deadly poison for the cell, and for this reason it is kept out of the cell. The concentration of calcium outside the cell is 10,000 times more than it is inside the cell. However, SR stores calcium in the cell in its own body. Thus, it both prevents the cell from being harmed and it provides the necessary calcium for contraction.

ER has the duty of eliminating the poison in the liver cells from the body by means of gall. For example, jaundice-causing bilirubin is a deadly poison for the brain especially in newborn babies. If jaundice is not treated, motor loss (paralysis) and intelligence loss can result from brain damage. Bilirubin and glucuronic acid combine by means of some enzymes on the surface of ER in the liver and are thrown into the gall bladder. In this way ER plays an important role in making foreign matter harmless and in reducing the side affects of medications to a minimum. Babies’ sensitivity to some medications during the first three months of life is due to ER’s not yet being developed enough to eliminate their harmful effects.

If it is taken into consideration that all of these mechanisms exist in human, animal and plant cells, it can be clearly seen that a broad and complex structure in such a small volume and its many functions can only have been placed there by the All-Powerful whose knowledge, wisdom, artistry, will and power permeate every moment and every spot.

Celaloglu is a freelance writer from Turkey with a degree in biology.

Spending so much time in the library for a particular book further amazed me about the answer I was searching for in my research. I am trying to understand how our genome is organized and how it functions. In order to make myself clear, let me first try to explain what the genome is. I bet you will be amazed by the impressive genome organization and its flawless function, too.

The genome can be thought of as a library. Each book in the “genome library” is what we call a “gene”. Every gene is different in size and the information they contain, just like the books in the library. Like the different sections in the library, our genes are also compartmentalized into different chromosomes. We have 23 pairs of chromosomes. One pair contains the information from our father and the other one from our mother. Therefore, unlike libraries, where you may find more than one copy of a book, our genome has two copies of each gene (except the genes on the X and Y chromosomes which carry only one set of genes).

Every cell in our body carries its own library: the genome. Our genome is the smallest library in terms of physical volume, yet contains relatively the largest amount of information. In our body, which contains roughly 100 trillion cells, we carry 100 trillion of these libraries. Here comes the amazing part; each of these libraries contains 3 billion letters of information. If this information were to be printed, it would take 1000 books of 200 pages each. The information in our genome is coded by a 4 letter alphabet; Adenine (A), Guanine (G), Cytosine (C) and Tymine (T). These four letters (A,G,C,T), called deoxyribonucleic acids, are the building blocks of every DNA strand on earth. The collective amount of these letters in any organism constitutes of its genome. We, as humans, have about 3 billion of these letters in our genome, which is encapsulated in the nucleus of every cell in our body. The total length of our genome is 2 meters long. This 2 meter long stretch of DNA (3 billion letters of information) is highly compacted and packaged in the nucleus, which is only 2 micrometer in diameter, an amazing 1,000,000 fold compaction!

How is our genome, which is 2 meters long, compacted so much that it fits in a nucleus only 2 micrometer in size? In the nucleus, DNA is wrapped around a group of 8 proteins called histones. This combination of DNA and histone proteins forms a special structure called “beads on the string”. Each bead is called “nucleosome” (Figure 1).

Multiple nucleosomes are then coiled together and stacked on top of each other. This organisation further packs the DNA up into a thicker fiber called “chromatin”. This chromatin fiber further condenses by forming tight loops. The structure which we call a “chromosome” is actually the most compact form of the chromatin fiber, which is only visible under the microscope during cell division. This remarkable chromatin organization allows a 2 meter long DNA to fit into the nucleus of each cell, an object so small that 10,000 of these nuclei can fit on the tip of a needle!

This remarkable genome organization further impresses us when we think about the utilization of this genetic information by over one hundred trillions of cells in our body. These many cells in our body are not all similar to one another. Most of the cells in our body are specialized to carry out specific functions. We have more than 200 different cell types specialized for unique functions. Some cells, like B and T cells in our immune system, are dedicated to fighting against infectious agents, whereas other cells, like neurons, function by transmitting signals between our brain and muscles. Since these cells have different structures and carry out different functions, they require different sets of instructions coded by genes in the genome. There are roughly 20.000 genes in our genome. Importantly, each specialized cell in our body utilizes only a subset of these genes, not all of them, at any given time. In other words, from the library analogy, roughly two third of the books (i.e., genes) are needed for each cell to function. The remaining one third of the genes is not necessary for that particular cell type. For example, the MYOD1 gene encodes a protein required for muscle cell differentiation. Therefore, this gene is absolutely required for muscle cells. However, the same gene is not required for the B or T cells that function in our immune system. While the MYOD1 gene has to be stored in an easy access location (open chromatin) for muscle cells, immune cells do not need this gene, and therefore it is stored in the depository section of the “genome library” (closed chromatin), which is not used very often.

In line with this, each cell has to organize its genome in a special way so that the genes needed for its function should be easily accessible. This remarkable genome packaging and organization allows each cell to easily and very quickly access the required genes for transcription into the proteins. On the other hand, those genes that are not going to be used are stored in relatively inaccessible regions in the genome library. Therefore, the genome is not packaged similarly all along. Certain regions of the genome are “open” and therefore easily accessible (called euchromatin) for transcription, while other regions are kept “closed” by condensed and packed structure (called heterochromatin). Since each cell type requires different set of genes, the genome is also differentially organized between cell types. Genome organization in a muscle cell is remarkably different than genome organization in, let’s say, a skin cell.

After all these explanations, I hear you asking, “How does each cell in our body know how to organize their genome? How does, lets say, a muscle cell decides to become muscle but not a blood cell?” These are exactly the same questions that many scientists are asking nowadays. Since the completion of the Human Genome Project (HGP)1,2, which determined the entire sequence of information of our DNA, scientists have been trying to understand how this amazing alphabet is being used in each and every cell in our body. Francis Collins, one of the great scientists of our time and the current director of National Institute of Health (NIH-USA), is especially noted for his landmark discoveries of diseases associated genes, as well as his leadership in the Human Genome Project. He calls the information coded in our DNA the “Language of God” in his recent book.3 Recent technological advancements allow scientists to better study the structure and function of this language and get better clues about the organization of this genomic library.

Whether we believe that this genomic information is “the language of God” or not, we are closer than ever to understanding the codes of this amazing language. New technological advancements allow us to get better insights about the organization and utilization of this information. The more we learn about it, the more we are amazed about not only its flawless packaging but also its differential utilization in each cell. At any time and in any tissue, trillions of cells are using different sections of the genome library to get the necessary instructions decoded from “the Language of God” and continue their journey in our bodies without any conscious decision making on our part.

Ahmet Mir Fazil holds Ph.D. degree in molecular Biology. He is a research scientist in Boston.

References

1. International Human Genome Sequencing Consortium (2001). “Initial sequencing

and analysis of the human genome.” Nature 409 (6822): 860–921.

2. Venter, JC, et al. (2001). “The sequence of the human genome.” Science 291

(5507): 1304–1351.

3. Francis S. Collins. 2006. The Language of God: A Scientist Presents Evidence for Belief. Free Press.

Dear Peter! I, your muscular system, would like to talk to you today; I allow you to walk and do all kinds of movements very easily. In the most recent essay of this department, the skeletal system, which works together with me, discussed how it protected your body and enabled you to stand straight and firm. Sure, this is true. However, as you know, huge rocks and trees can stand straight, too; but they do not have what you do-the ability to move. They are rigid and inflexible because they do not have a system that allows them to move.

You on the other hand, as the most splendid creation in the entire universe, have mobility. All animals have mobility at different levels, thanks to the muscular tissues, which work dynamically behind all the moving organs. However, you, human beings are like neither the animals nor the plants. You have not been created to live like a tree that is pegged down in earth or like an animal that unconsciously tries to meet only its biological needs. Our Designer, God, has made you and your descendants the most important of all creation. He has given you qualities that help you to discover the world, learn, invent and establish new civilizations. To realize such potential and to carry out such duties, you need to first have the freedom to make changes in your small immediate world, which can only be done through motion. In order to enable you with this ability to move, my Creator has put me at your service. I am a system that comprises hundreds of muscles and millions of packed cells.

My most important feature is the cells that move by burning sugar, like a motor consuming fuel in order to work. My cells can shorten and lengthen thanks to the intracellular fibrils (myofilaments) that contract and expand. As a result of each contraction, I pull the bone or the organ that I am attached to and cause it to move or change shape. With the exception of your heart, your bones and organs cannot move on their own. Their ability to move depends on the nature of the muscle they are attached to.

Indeed, I can be called both an organ and a form of tissue. I can use my contraction ability not only as muscle tissue, but also as an organ and a system which runs throughout your body. That is the reason why I appear in so many different types and shapes of muscle bundles. Let me give you an example to help you better understand what a muscle consists of: Let us imagine that a thin thread is like a basic muscular cell. Let us now bring together a great number of threads and make string out of them. Then, let us bring together those strings and make a clothes line. Next, let us bring together a great number of clothes lines and make a very thick rope. Now, imagine this thick rope as a muscle and an organ. Yet, this example is too basic compared to the sophisticated muscle.

Very thin cotton fibrils make up the thin threads. In the muscle fiber, like those cotton fibrils, there are two filaments formed by the two types of protein molecules called actin and myosin, which help in the contraction function. Those little filaments are placed facing one another and they slide past each other during the contraction, which causes the muscle fibers to shorten. That is how the contraction and relaxation of a muscle occurs.

Peter, do you think that coincidence plays a role in this complex and wonderful mechanism and the incredible structure which I have attempted to simplify with an example? Not even a simple thread can be produced without a thread-maker or a machine. Each of your muscles comprises billions of fibers, wrapped all around your bones and giving shape to your body. Can such a complex and delicately intricate structure exist on its own and be positioned in the best place it could possibly be?

My muscles consist of bundles that are made of thousands of muscle fibrils; the size and shape of each muscle depends on which bone it is attached to and what function it does. For example, the muscles that move the bones in your arms and legs are long and spindle-shaped; whereas the ones that are attached to your body can be circular, or triangular, or spread over a broad area. Whatever shape they have, the red skeletal muscles, which are attached to your bones, are very strong and they are voluntary muscles, which mean you can control their movement. When you walk, run, do something with your hands, lie down or stand up, you always use my red striated muscles. The strias (stripes) can only be seen under a microscope because of the histological structure of these skeletal muscles that make up a great part of your body.

My smooth muscles are involuntary muscles that work without your control. Their movements are slow and their contractions last longer, which is the reason why they do not tire easily. The smooth muscles lie in the walls of digestive system, blood vessels, and urinary tract, but I will not talk much about them since each system has referred to the smooth muscles within itself and in detail in previous talks. Because they are not attached to your skeleton to work, the smooth muscles do not play a role in your movements, such as walking around; they only work for the movements of your inner organs.

The third type of muscle belongs to your heart (cardiac muscle) and although the heart has a little striated muscle tissue, it, too works involuntarily. Therefore, you should be aware of the fact that it is the striated muscles which work for the movement of the skeleton and do the major job, and that it is this that we refer to when we say “muscle.”

A great number of bones have been created in order to support your body, and joints have been placed between those bones for them to take the proper shape according to every movement. However, none of those joints have the ability to move by itself. A door or a window, no matter how good it is, cannot be opened or closed without an outside force to pull or push it. In the same way, a joint needs a force to move it and that force is produced by your muscular system. There are around 340 muscles included in your muscular system. It has been estimated that all the muscles in your body perform 510 different functions! While some of those functions are bone movements in your joints, other muscles can perform movements without moving a bone at all. Muscles that are placed in your forehead, face, eye lids and abdomen are those kinds of muscles. They can help you look worried by wrinkling your forehead or grimacing when you are disgusted by something.

Keeping with tradition, the muscles that are included in my system have been named based on the function they perform. For example, the muscle which moves an organ part towards another part is called an abductor, while the muscle that straightens a joint is an extensor, and the muscle that bends a joint is a flexor; the muscle that raises a part of the skeleton is a levator, that which the muscle makes a part of an organ prone is a pronator, the muscle that rotates a part of an organ is a rotator and that which brings an organ into a supine position is called a supinator.

In order for you to make all the movements that your body needs, my muscle components have to be both very strong and flexible. The most important feature of my muscle components is that they can be trained and strengthened with a systematic workout. The main goal of all sportsmen who compete is to increase the strength and the endurance of their muscles. As a result of intense exercises with weight and speed, the number, the diameter and the length of my muscle fibers will increase. Thus, I can gain more power to be able to do more work and also gain the ability to contract faster.

However, in addition to all this training and exercise, genetic factors also play a role in my health. For this reason, not everybody who works out can become a good sportsman; but if the person has innate muscular and skeletal capacity, with good exercise this capacity can certainly be enhanced and developed. However, if a person does not have the proper muscular structure for a particular sport, it would be unfair to expect them to be a champion! Although my muscles always seem to be of the same type at first sight, I might show different behavior depending on the distribution of the special fibers inside them. Some of my fibers twitch fast and tire easily, some of them twitch slowly and tire later. Depending on the distribution of these different fibers, the movements and sport that every person can do differ from person to person. In this case, an athlete who can run only 100m and an athlete who can run 10,000m do not have the same development of muscles; they have different amounts and distributions of special muscle fibers.

The contraction of any of my muscles can occur in two different ways: If the pressure put on my muscle is stronger than the resistance of the tissue, the tension remains constant and the muscle shortens. This is called an isotonic contraction. If the pressure put on my muscle is equal to the resistance, the tension of my muscle increases and its length does not change. That is called an isometric contraction. The amount of force that occurs during the contraction of my muscle depends on its length and the amount of the stimulus.

In order to produce muscle contraction, an electrical signal is sent through a motor neuron to the synaptic gap, which is positioned between the muscle cell membrane and the nerve cell. As a result, a chemical reaction occurs, which, in a very short time, causes the actin and myosin proteins in the muscle fibril to slide past each other and thus shorten the fibril, contracting the muscular cells. During this reaction, the temperature also rises a little and the total heat generated by all the muscles determines your body temperature. For this reason, in cold weather, my muscles vibrate, increasing your body temperature and trying to maintain it. You may now understand why moving the parts of the body in cold weather helps people avoid from getting sick or freezing. As you can see, every act of my Creator is quite purposeful. He can create two or even more functions within one task: Through your muscles, He not only provides you with the ability to move freely, but heat is also produced and you are protected from getting cold.

When a muscle fiber contracts frequently as a result of successive electrical impulses from a nerve fiber, it becomes tired after a while and needs rest. In this case, other muscle fibers which have not contracted for a while will take over and continue the job. However, if the electrical impulses from the nerve come too frequently and my muscle fibers do not have an opportunity to rest, a condition of constant contraction, which is known as physiologic tetanus, occurs.

The tension receptors that are placed on my muscles help maintain the harmony and coordination of all your movements including walking and running, bouncing and sitting down. They do this by constantly signaling the nerve system and providing feedback about the condition of my muscles, and about the speed and the intensity of contraction. Thus, through these receptors which control and coordinate my muscle activities, the well-being of my system is ensured. It is this that prevents you from wobbling when you walk, or helps you to take a spoonful of soup to your mouth without spilling it.

Like any other tissue or system, I, too, have some special disorders. The most common disorders are: weakness, malformation, muscles that develop and move involuntarily and habitually, especially in your face (tic), infected muscles (myosite), muscle dystrophy, muscle rigidity (the Stiffman Syndrome), benign or malignant muscle tumors (leiomyom, rhabdomyoma, or Rhabdomyosarcoma). These disorders differ in their degree of severity and risk.

Dear Peter! You have now seen that each muscle helps your organs to move, holding your bones and giving shape and function to your body, making you a beautiful model and an inspiration for sculptors. You may have understood that this is a work of knowledge and might; there is no way that the myofibril in my one cell could form by itself as a result of a coincidence.

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

The muscle cells are responsible for the strength and tone of the vessels. Today, we know that the role of the endothelial layer goes beyond a simple physical barrier. In addition, there are twenty-five different substances secreted by the endothelial cells that play a role in blood clotting, cell proliferation, the regulation of vessel permeability, and the functioning of the immune system. The endothelial cells are 10-15 &μm wide and 20-25 μm long. They are located in the inner vessel wall in a single-cell layer. The total endothelial area in the body of an adult is around 5000-6000 m², and it weighs around 2.5 kg. Endothelial cells during inflammation Capillaries consist of an endothelial structure; they can only be seen under a microscope, but their total length is nearly 96,000 km. The blood brought by the arteries is conveyed to the vein through capillaries. At this stage, the gas, liquids, and nutrients are brought out through the vessels and the cells and tissues around are supplied with oxygen and nutrients. In return, the liquids that they discharge and other waste matter are conveyed to the vein through capillaries. This matter-exchange, which occurs both inside and outside of the capillaries, is regulated thanks to the permeability of the endothelial cell layer and the pressure balance of the capillary system. During cardiac failure and inflammation, liquid release is increased due to a pressure imbalance and the liquid retrieval is not sufficient to make up for the amount lost. This results in swelling in the area in question. Here, we need to underline that inflammation, which appears with symptoms such as edema, redness, fever, and pain, is not a harmful process. On the contrary, it is a miraculous defensive mechanism granted to our body; inflammation protects the body against serious damage. For instance, the inflammation that forms around a bee sting prevents the venom from spreading throughout the body. The endothelial cells are given an important role in the inflammation as well. The chemical molecules secreted by the endothelial cells in the inflamed spot cause the vessels to react by enlarging and thus perfusion is increased. Later, the endothelial layer becomes ready for leukocytes to settle; these are used in neutralizing the substance that caused the inflammation in the first place.

Balancing blood pressure

The layer of smooth muscle cells is stimulated with chemicals secreted by the endothelial cells and the tone of the vessels are controlled through the constriction and relaxation of the vessels. Therefore, an important duty in the regulation of blood pressure is given to these cells. During aninfection, bacteria circulate in the blood stream and the blood pressure falls extremely low. Tissue nutrition is upset (septic shock) and an excess of muscle-relaxing substance is released by the endothelial structure. Veins and arteries become too relaxed and there is a considerable drop in blood pressure (hypotension). On the other hand, with problems like atherosclerosis, the endothelial cells cannot fulfill their duty and due to a deficiency in nitrogen oxide, they become immune to the stimulus to relax the muscles. The resulting problem in this situation is hypertension.

Endothelial cells prevent hemorrhage

In order for a hemorrhage to stop the vessels that are bleeding need to narrow down. This is very important in the first stages of blood loss, particularly when there is a problem with blood clotting. When a hemorrhage begins, the endothelial cells are ordered to excrete a substance called endothelin. This starts the narrowing down of the bleeding vessels. Endothelin is not excreted in normal vessels. When the umbilical cord of a newborn is cut, it prevents the baby from losing blood.

Endothelial cells in blood clotting

The duty of endothelial cells can prevent or facilitate blood clotting, depending on the situation. First of all, they prevent the blood cells from adhering to the vessel walls and prevent clotting inside the vessels. Imagine water flowing through a pipe. The speed of the flow is greater in the center and lower at the periphery. Therefore, in the long run, some residue forms inside the pipe. In the veins and arteries, the flow of blood near the walls is also slower. To prevent the formation of any residue, both the endothelial cells and the blood cells are created with negative loaded surfaces and the blood cells are pushed towards the center. In addition, a substance called prostocyclin (PGI2) is excreted and the thrombocytes change their structure. As a result, residue formation and clotting is prevented along the vessel walls. In a case of any long term damage to the endothelium (e.g. due to smoking, diabetes, or hypertension), the relevant protection mechanism fails, and clotting inside the vessels results in thrombosis. Some serious cases can even necessitate the amputation of a limb. The endothelial cells can also facilitate clotting when necessary. In case of bleeding due to a wound, they function contrarily and help the blood to clot to prevent blood loss.

Endothelial cells in the bone marrow, the liver, and spleen

As a divine blessing, the endothelial cells form a looser layer in these organs and vessel permeability is increased. Thanks to this increase, matter Exchange with blood is easily realized; blood reaches these organs, which are responsible for the constant control of the contents of the blood, easily.

Endothelial cells in the brain and eyes

The endothelial cells in organs like the brain and eyes are very closely integrated forming a barrier between the blood and the organs. This is to such an extent that the major nutrients of the brain, like glucose and oxygen, pass without any obstacles, but several chemicals, including medication, are blocked by the selective-permeability of this protective mechanism. Research has proven that various substances injected into the bloodstream reach almost all the tissues except for the brain. Thanks to the efficient protective mechanism that has been given to these minute cells, the brain is saved from a great deal of negative effects. Even a single cell is not left to chance and nothing happens randomly. As can be seen throughoutthe universe, opposites are made to work hand in hand in the human body as well in a splendid harmony for the continuation of life.

References

• Vinay Kumar, Abul K. Abbas, Nelson Fausto, Richard Mitchell, Robbins Basic Pathology, W.B. Saunders; 8th edition, 2007. Hall, John E., Arthur C. Guyton, Textbook of Medical Physiology,

At the same time as these events are happening almost simultaneously, information from my eyes and my finger is being sent to the brain so that my finger will move in the way I expect it to. For example, if the path of my finger’s movement is somehow blocked, my brain can redirect it.

However, the event described above is not that simple. Starting from the neurons and continuing until we reach the muscles, every element that acts during this process displays extraordinarily complex alterations at both cellular and molecular levels.

Consider muscle cells, since they are moderately well understood. Upon arriving at the muscle cell, the electrical impulse causes the voltage-sensitive calcium channels in specific compartments within the cell to open and release calcium into the cell. You might remember from high school biology that muscle contraction is the result of two proteins (myosin and actin) sliding over each other. Normally, actins are masked by proteins known as tropomyosin. During the waiting period, therefore, the interaction between myosin and actin, which leads to contraction, cannot occur. This is why the muscle cell releases calcium, for when calcium is free in the cell, it binds to tropomyosin and enables it to move. As a result, actin is free to interact with myosin.1

After that, millions of molecules containing energy, known as ATP, bind to millions of myosin proteins, and the muscle contracts. When the contraction ends, the freed-up calcium is stored once again in specific compartments. When calcium is not present, tropomyosins again mask the actin proteins, and millions of muscle cells revert to their initial position, ready to respond to another contraction.

I realize that all of this is hard for the average reader to understand. However, the events that take place are even more complicated.

Expressions like “ATP binds to myosin” and “calcium is stored in compartments” are, in fact, simplified ways of explaining a highly complex event. Since there is a reason for everything, our cells should contain something that is performing these functions and carrying out such events. If we expand this problem to its limits, we will have to understand that each cell contains a large set of rapid and specific chemical reactions that occur constantly and yet do not interfere with one another. Based on current scientific knowledge, we can say that enzymes conduct almost all reactions in a cell, and that DNA has all the necessary information to produce enzymes. Enzymes are protein molecules that speed up and regulate all of the reactions that take place in a cell. If there were no enzymes, the reaction that a cell carries out in seconds could only be completed in thousands of years, and consequently, life as we know it would not exist. Life requires that the correct enzyme be found in the correct place and at the correct concentration.

Based on this, let’s revisit the above example. When the electric impulse reaches the muscle cell and calcium ions are released, this and every external and internal signal is conveyed to the DNA through a mechanism that we are just beginning to appreciate: signal transduction. Later, RNA is produced in those regions of the DNA that are responsible for producing the enzymes that enable the cell to give the appropriate answer (RNA helps DNA to produce enzymes). The synthesis of the enzyme is regulated at various checkpoints, such as during RNA production or RNA translocation out of the nucleus by other enzymes.2 ATPase, one of the many enzymes produced, makes it possible to use ATP, while another enzyme makes sure that the ATPases are in the correct location in the cell. Meanwhile, in order to sustain life, thousands of other enzymes conduct various reactions at the correct time and place. Therefore, when I move my finger, the number of active elements increases enormously.

Let’s look at the finer points of the cell. Using a simple calculation, in which each number is much smaller than the actual number used, if we assume that one million cells perform some kind of action from the reception of the first impulse in the brain until the time the muscle contracts, and if we calculate that one thousand reactions occur in each of these cells, this means that one billion reactions are performed for the simple action of moving a finger. One billion reactions, in just one second. And at the same time, my heart is beating, new blood cells are being produced, my eyes are sending visual information to my brain, my kidneys are filtering my blood, my lungs are exchanging old air with new, fresh air, my digestive system is supplying the necessary nutrients to my blood stream, and much, much more. Moreover, all of these are continually taking place. The fact that all of these actions are occurring, again based on a very rough and simple calculation, means that maybe one trillion reactions are occurring every second. As a result, a person might feel that it is quite possible, at any instant, for this perfect machine-the human body-to fall apart.

Realizing this, one might actually find it hard to believe that he or she is really alive. For example, I would never believe that such a machine would work if I did not have the empirical knowledge that it does work. How, for example, can I believe that I can produce one trillion reactions every moment and never confuse one with another, that it takes one billion reactions to move my finger, and that one trillion gears are working by themselves without making any mistakes?

With this idea in mind, I see the following lines in Epitomes of Light: “Also, since a building that contains every kind of artwork and riches cannot exist without having been built by someone, the existence of this universe is intimately connected with the existence of the Builder. If someone thinks carefully, it is impossible to accept one without the other.”3 Upon reading these words, I start to realize that all of these gears are not working by themselves, but rather that every second all of the trillion gears are being regulated by the One for whom nothing is difficult.

Suddenly, I remember that whenever the names of God are recited, I hear the name al-Hayy right next to al-Qayyum: God is He besides Whom there is no god; He is al-Hayy (the Ever-Living), al-Qayyum (the One Who sustains and protects all that exists) (Qur’an 2:255). Putting al-Qayyum next to “life” indicates, at least to me, that every living being is kept alive at each instant by al-Qayyum. If His control over each person’s existence were to be lost for even one second, one trillion gears would become irreversibly mixed up and the body would fall apart instantly. While thanking God for all that He has given me, I realize that I cannot thank Him enough for even one gear.

References

1. Harvey Lodish et al., Molecular Cell Biology, New York: Scientific American Books, c1995, 1027-29.
2. Lewin, Benjamin, Genes VI, Oxford, NY: Oxford University Press, 1997, 847.
3. Nursi, S., Epitomes of Light: Mathnawi al-Nuriya: The Essentials of the Risale-i Nur, Kaynak A.S., 1999.