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.

The harmful foodstuff eaten is spat out quickly through vomiting and so damages of such foodstuff is minimized. Occurring upon taking of any poisonous food or alcohol, vomiting directly contributes to treatment by ensuring a quick disgorge of the harmful stuff. Variations in amounts of estrogen and progesterone hormones during pregnancy helps in noticing even the least amount of toxins (poisons) found in the blood by way of increasing sensitivity of the chemoreceptor trigger zone within the brain stem. When this zone of the brain takes notice of toxins in the blood, it immediately activates feeling of nausea and vomiting. Margie Profet, a researcher from the University of California at Berkeley was the first person who drew attention to this issue in 1995. She asserted that food craving is a divinely merciful mechanism aiming at protection of the miraculously developing embryo against probable dangers within the human body. She also asserted that food craving protects the embryo from natural toxins in foods. Vomiting may also happen to travellers and sufferers of migraine. Certain psychological factors such as unpleasant smell and excessive fear may result in vomiting as well.

If, however, vomiting recurs and turns out to become a habit, one should be careful, for vomiting causes new problems such as electrolyte losses and dehydration while irritating the alimentary canal, throat, mouth and teeth through which vomited matter passes. In addition to these, regurgitating might be inadvisable and indeed should be avoided in certain cases of poisoning which develop due to ingestion of petroleum products and burning chemicals like hypochlorite and ammonia which are used in house cleaning. The reason for this is because petroleum products may cause pulmonary infection of chemical origin in the lungs and burning chemicals may cause scalds on the tissues they touch during regurgitating.

Just like all the systems that our bodies are equipped with, vomiting also happens in accordance with a plan and program during which a wonderful co-ordination is displayed. The vomiting center in the brain is responsible for such co-ordination.

Rapid increase in salivation and nasal secretion prior to vomiting plays a key role in alleviating damages of the highly acidified vomited matter over the interior surfaces of the mouth and nose. Increased salivation helps with the protection of tooth enamel too. The pushing process of the foods eaten normally occurs from the intestines towards the bowels during the course of digestion. However, it reverses and occurs from the intestines towards the stomach during which the muscles of gastrointestinal tracts relax, open and the contents of the intestines are thus gathered in the stomach. Taking deep breaths prior to vomiting decreases the need for breathing during vomiting and blocking of the air passage by vocal cords’ converging prevents aspiration, that is, the passage of contents of stomach to the lungs. If such mechanisms did not exist, every vomiting attack might have ended catastrophically. Breathing attempts apply negative pressure on the rib cage and convulsion of stomach muscles applies positive pressure within the abdomen in spite of the converging of vocal cords. A pressure decrease is observed in order for contents of the stomach to be regurgitated. Muscles of the gastrointestinal tract tighten while muscles of the gate between alimentary canal and stomach relax just before vomiting. So, regurgitating via alimentary canal occurs without passage of stomach contents to intestines. Upon completion of vomiting, there is the disappearance of abdominal convulsions and the secretion of endorphin in the blood, so a person breathes sigh of relief.

In conclusion, although vomiting is perceived as something which is seemingly unpleasant, it is indeed a fine product of Divine artistry like all other systems and mechanisms of our body. Vomiting, as one of the proofs that God has created nothing useless and unnecessary, is certainly a great blessing bestowed upon us.

References

• “Sickening sounds – research to make your ears cringe.” University of Salford. January 28, 2007.
• Lunsden, K, and Holden WS. 1969. “The act of vomiting in man.” Gut 10: 173-179.
• Margie Profet (1995) Protecting Your Baby-to-Be: Preventing Birth Defects in the First Trimester. Reading, MA: Addison-Wesley. pp. viii, 312.
• Flaxman, S.M. and P.W. Sherman 2000. “Morning sickness: A mechanism for protecting mother and embryo.” Quarterly Review of Biology June 2000. 75:1-36.

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.

There are so many blessings in life, granted to us free of charge, which we take for granted. Eyesight, being able to see near and far distances, most certainly tops the list. But we do not have to be deprived of our sight in order to understand its wisdom and functioning, and to contemplate upon its true value and worth.

Years of research and hard work were dedicated to develop cameras and multi-featured objective lenses. Initially, one to three lens objective cameras were used for simple shots, whereas today, objectives with seven to ten lenses are being used to take better photographs from a snow drop falling onto a flower to a buzzing bee resting on a flower. I wonder to what extent human beings are aware of the pair of eyes that has been bestowed upon them by God, and its ability to see different colors and shapes both near and far. Unfortunately, as people who often understand the true value of things once they are lost, we understand the blessing of being able to see near after the age of forty when we cannot read the newspaper without glasses and when we cannot put a thread through a needle.

So why is it that we can still see far after the age of forty but fail to see near? In order to understand this we need to examine the structure of the eye and its functions.

The structure of the eye and the ability to see

The exterior part of the eye is made up of a translucent layer (cornea) at the front and a white protective layer (sclera) behind it. The vascular layer of the eye (uvea) is located in the middle of the sclera. The most inner part of the eye is made up of the retina, the light-sensitive layer of tissue responsible for converting light rays into electrical signals. The hole located in the center of the iris, the colored part of the eye, is called the pupil. Behind the pupil is the crystalline lens. For a clear vision, lights reflected from objects need to be focused on the central part of the retina (fovea). While cameras have lens systems to focus the image on the film, it is the cornea and crystalline lens that are responsible for the same function in the eye.

Refraction power of cornea is constant and around 43 diopters. The refraction power of the eye lens when resting is around 20 diopters. Light rays coming from outside refracts at a set ratio and manages to focus on the retina. The light rays coming at the retina are then coded into electrical signals. Afterwards these signals are routed towards related regions of the brain via optic nerves. Most of the stimuli relayed by the optical nerve arrive at the visual center of the brain (occipital cortex). These coded electrical signals then become vision when they reach the optical lobe of the brain.

The function of the lens and accommodation

The refraction power of both the cornea and the lens (43+20+63 diopters) is sufficient to focus an image on the retina when looking at objects farther than 6 meters. Extra refraction power is needed for closer distances in order to focus images on the retina. Mobile lens systems enable this job to take place in camera objectives. Since refraction power of the cornea in human eye does not change, this additional task of refraction is set to be provided by the ocular lens. It is built as a flexible structure without any blood vessels. Aqueous humor (lens fluid) which is secreted by the ciliary body is responsible for lens nourishment, removal of waste products and toning of the eye since the lens does not contain any blood vessels. This internal fluid has low oxygen concentration therefore the lens is made to derive its energy supply mostly from anaerobic metabolism.

The iris is positioned in a suitable place where it can change the shape of the internal lens behind the pupil. The lens in this special place is suspended into position via zonule of zinn ligaments attached to the eye as a ciliary body. The ciliary body contains ciliary muscles where zinn ligaments are attached. Only 0.5 mm of space exists between the lens and the ciliary body. Zinn ligaments are tight when ciliary muscles are resting and this enables a flatter configuration of the lens. Upon contraction of ciliary muscles, zinn ligaments become relaxed and the diameter of the lens decreases along with an increase in its thickness. Thicker lens becomes more globular and this increases its refractive power, thus enabling vision of the closer distances. This increase in refractive power of the lens in order to see closer objects is called “accommodation.” If the stimuli of the ciliary muscles expire, ciliary muscles then relax making zinn ligaments tighter, reducing thickness of the lens, making it flatter and therefore less refractive. This reshapes it to focus on distant objects for a clearer vision.

Accommodation mechanisms and loss of accommodation during aging

The vision blurs temporarily when one takes an immediate shift from staring at an object in the distance to another object nearby. As soon as this blurry image reaches the occipital cortex, stimuli generated here arrives first at the Edinger-Westphal nucleus via special nerve tracks and then to the ciliary muscles of the eye. In a very short time, this blurry vision is corrected and becomes clearer without us even noticing with optimal increase of refraction in the internal lens. In a time as short as 0.35 seconds, for thousands of times in a day, this mechanism is set to function in such a perfect manner to spur those thoughtful minds into reflection and wonder.

Accommodation ability is at its highest point in children and this feature of the eye decreases with age. Refractive power of the lens can increase up to 34 diopters with a 14 diopters accommodation power along with 20 diopters of resting refraction during childhood. This way, children can clearly see objects as close as 7 centimeters. Accommodation power decreases with age. It reduces to 4-8 diopters after the age of 40 and 2-3 diopters around the age of 50. It is widely accepted that refractive power disappears entirely after the age of 60.

In the advanced stages of aging, the eye lens loses its transparency, becomes cloudy as it develops cataract. Eye lens in this poor transparent stage is removed via cataract surgery, to be replaced with an artificial lens to carry out the refracting task. Unfortunately today, technology is still unable to produce an artificial lens that is capable of all the tasks that a human eye can perform. Artificial internal eye lenses that are used in surgeries today cannot carry out accommodation functions. Majority of these lenses can only focus on one point at a near or far distance. Newly developed multifocal lenses can utilize various mechanisms to see both near and far distances yet they are not in any position to replace the human lens completely.

Ocular motions when looking near and far

Thanks to ocular movements, we do not have to move our head constantly while looking around. The eye movement involving both eyes in which each eye moves in the same direction is referred to as version type movements. Another movement type is called vergence, and this is when both eyes move in opposite directions. Vergence type movements are a type of ocular motility coded in a special center part of the brain. It is called convergence because the eyes get closer to each other when looking at closer distances, and called divergence when both eyes focus on the same spot by directing away from each other. If eyes only moved in the same direction without this convergence mechanism, both eyes would not be able to focus on closer points and would not be able to develop three dimensional visions (depth perception).

In addition to accommodation and convergence, when we look closer, our pupils get smaller (Miosis). Light rays coming from outside objects get improved focus on the retina via this constriction of the pupils. This way, a clearer image is provided.

When we look closer, accommodation, convergence and miosis all happen at the same time in a synchronized manner to provide a clear vision. The details of these complicated chains of events have yet to be understood.

Conclusion

The fineness of refractive power of the eye with a single lens, accommodation ability and sensitive balances of ocular motility is only a few of the blessings of the eye granted to humankind. The ability to see near being at its peak during young ages when learning is most active is another dimension to this miracle. These wisdom-filled capacities given to the eye makes one ponder upon the importance of the eye for survival, in addition to being a reminder to those with an open mind and heart to gaze upon the natural world and contemplate upon the Almighty.

Octopuses are equipped with a very powerful sensing system in addition to their sharp vision. For example, an octopus whose vision is obstructed can sense the size of objects and the distance between them. Regulation and synchronization of vision is realized with internal and external movement of the lens contrary to human beings. When it faces a threat, the octopus releases dark blue-black ink and tries to repel its enemy. Immediately after the spray, its color changes and it carefully leaves that spot. The secretion glands found in the inner face of the bladder have been programmed to secrete ink the moment the animal becomes frightened. Another function of the ink is to blunt the attacking animal’s sense of smell. Even if the animal touches the octopus at this time, it cannot recognize it.

Another striking and important ability given to the octopus is its ability to camouflage. In some situations it tries to protect itself from danger by hiding itself with this capability. If it has not been able to find a suitable place to hide, the octopus swims among the corals and, taking on the color and shape of its surroundings with the help of color cells comprised of richly colored matter (chromatophores) found under the skin, it camouflages itself perfectly.

At first glance the suckers of an octopus are no different from suction cups vacuum pressed onto smooth surfaces. However, in reality this organ is more complex than it appears to be. This organ was not created just for the purpose of sticking on objects. By means of muscles unique to it, the octopus is able to make various maneuvers.

There are approximately 200-250 suckers in two lines on each arm of the octopus. This means there are approximately 2 thousand suckers on its eight arms. There are two small chambers on each sucker. The external chamber is called a cone and the internal one is called a pot. When it sights its prey, the muscles of the external cone take the shape of the surface of the prey and completely cover it. The muscles of the internal pot structure are full of water and, disconnected from the outside world, decrease the inner pressure. This difference from the outside pressure has the effect of a vacuum. The external muscle structure enables the octopus to turn from an erect or parallel angle by decreasing the pressure difference around the object and without destroying the functional structure of the sucker.

In addition to possessing the complex muscle structures explained above, the suckers have an amazing nerve system. The chemical receptors found on the edge of the suckers (chemo-receptors) give feedback regarding the taste of the object, and the pressure and position receptors give information regarding pressure and touch. The nerves of these receptors, gathered in a node, act as a tiny brain. The chain structure extending the length of the octopus’ arm connects the suckers and nodes and synchronizes them. This structure enables the animal to lift and raise its arms without need of a command from the main brain. How this amazing task is accomplished by the brain, arm and suckers is a subject that needs investigation.

Only considering its suckers, the octopus appears before us as a creature adorned with perfect artistry and special capabilities. The characteristics of these animals being in a wise and most appropriate form is one of the clearest proofs of the blessings and benefaction of a compassionate and merciful Creator.

Canoglu is a freelance writer from Turkey with a degree on zoology.

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.

Some people might see me as a rough piece of flesh that wiggles in the mouth. Of course I am not that simple! By looking at my color, some experienced doctors can even diagnose an illness. For example, some well-known symptoms that I show are whitening due to fever, becoming dark brown when you have typhoid, blackening because of a yeast infection, or having a smooth surface because of anemia or lack of niacin (a B-group vitamin).

If you are wondering what my primary duties are, I can say that the first is to help to produce speech, an ability which distinguishes you human beings from animals. For sure this speech production is not only mine. First of all the brain, which is the coordinator of all the organs including me, regulates all my movements in speaking. The other organs that help me form sounds to make words are your teeth, lips, palate, the vocal cords in your throat, and your lungs, which work like an air pump and vibrate those cords. As you see, so many of us work together just to produce your speech.

Other than the speech function, my second major duty is to work as an inspector to taste and process the countless fruits and delicious foods that are given by God. That is how you get an idea about an animal- or plant-based substance that you want to eat. If I did not exist, you might die because of a poisonous plant that you ate out of hunger. Many poisonous substances have a bitter taste. Indeed, I can sense their bad taste the moment I touch them and warn you to spit out the thing in your mouth immediately. When you eat sweet and delicious things, however, I make you remember and thank God, who has given them to you. However, you should be careful about my fondness for taste and control yourself since that is part of a God-given test. My Creator has made a relation between my love of taste and the evil-commanding side of your soul. He has also made me a step for your spiritual development. If you eat and drink too much, which means you are misled by your evil-commanding side and abuse my sense of taste, it will be you who lose. I do what my duty requires and get the taste of everything. But it is your job to use your will power and not to be defeated by your evil-commanding self (nafs). I will never stop you, whether you eat one piece of baklava or ten; I will get the taste of every piece. Do not ever blame me for that!

I have another function that many people are not aware of. My movement causes a negative pressure in the cavity of the mouth. Are you wondering what this negative pressure does? This pressure is needed especially for babies to nurse on their mothers’ breast easily; I help them in the sucking movement. In addition to that, as everybody knows, I have very important functions in chewing and swallowing food. I manipulate the food in your mouth; I soften and moisten it with saliva so that it can be easily swallowed. Also, during swallowing, I move the food back toward the pharynx. I have to be very careful while doing all this, since at my smallest mistake, your teeth might bite and hurt me.

Of course, I can do all this only with the help of my Creator, who has built my anatomy of delicate tissues and cells. Since He never does anything absurd or useless, He has given every organ qualities that are both esthetic and functional. My main body consists of seventeen muscles, eight of which are in pairs. They extend in all directions. Among those muscles are the lipid membrane and some salivary glands. I am the most flexible organ in your body. My many strong muscles enable me to move in lots of directions easily. Those muscles are covered by an epithelial lining which is called the mucous membrane. The small projections on my upper surface are called papillae. These papillae are of several types. They contain receptors which allow you to sense taste and the salivary glands that help me stay wet all the time. The papillae cover as far as an A-shaped line towards my back which makes up a third of my length. Here at my back, there are plenty of salivary glands and the lymphoid tissue, also known as the lingual tonsil. Many germs that enter through your mouth get trapped here. The papillae are named according to their shapes. The filiform papillae (which are long and thin) do not contain taste buds. They only provide a rough surface to move the food easily. The food is moistened by your saliva and crushed by your teeth. Then, with the help of these papillae, I help to shape the food into smaller pieces to make it easier to swallow. The fungiform papillae are mushroom-shaped and scattered among the filiform papillae. They are located at the center of my top surface and they contain taste buds. The circumvallate papillae lie along the A-shaped line which makes up the border of my back. These papillae are larger in size and smaller in number; there are around thirteen of them. Each taste bud on the fungiform papillae has 50 to 75 receptor cells which live for only seven to ten days. When cells die because of hot or acidic foods, new ones are created to make new nerves for the taste buds. Only substances that are dissolved in water can reach the taste receptors. That is why I cannot taste a dry substance that you have taken into your mouth right away; it has to be moistened and softened first. Tasting occurs in the receptor cells of taste, where some analyses are undertaken much more delicately than in a chemistry laboratory. My receptor cells change this chemical stimulus into an electrical stimulus and send it to your brain. This electrical stimulus allows the sense of taste to be perceived.

Among the many kinds of taste, there are four major groups. The taste buds for sweetness are located near my front; the taste buds for saltiness are scattered widely on my surface; the taste buds for bitterness are found at my back; and the taste buds for sourness are on my sides.

My under surface extends between my tip and the floor of your mouth. The mucous membrane that covers this surface is smooth and does not contain papillae. It is purple in color because of the many blood vessels that are inside me and nourish me. By the way, the famous saying that “the tongue does not have a bone” is wrong, since I do have a bone. However, this bone is not located in my front body, which is why I am very flexible and I can say whatever you command me to say. But by my muscles and ligaments I am firmly bound to a U-shaped bone (the hyoid bone) at my root. I am connected to your lower jaw by this bone.

I can have disorders, like every other organ. In fact, many disorders in me are an indication of disorders in the other organs or of a metabolic illness. For example, mouth ulcers can often be seen on me. Some types of mouth ulcer are caused by stress, lack of sleep, or lack of vitamins. Others occur as a result of absorption disorders and as a symptom of Behcet’s syndrome. Some ulcers can last for weeks and they can be very painful. You might suffer from this pain especially when you speak and eat. Diseases such as syphilis and herpes also show themselves as ulcers on me. I might even become cancerous in people who smoke or in those who eat and drink things that are too hot. I sometimes show the symptoms of some metabolic disorders like Down’s Syndrome, the blockage of lymph vessels, glycogenosis and amiloidosis. In these disorders, my muscle mass shows excessive growth due to abnormally deposited glycogen and amyloid.

Dear Peter, until now, your “speechless organs” have talked about themselves in their own tongue. I have always talked, but I have always talked on your behalf, expressing your thoughts and feelings. It is you who are responsible for what I have said, good or bad, since I am bound to your will power. However, today I spoke in my own tongue, and on behalf of our Creator. As is well known, I am an organ that has great potential for both evil and good. It is your duty to control me and use me well. Do not ever forget that I am not a simple mass of muscle, epithelium and nerves. Rather, I am a tool that can be used for both debasing and elevating you. From now on, when you eat an apple, do not swallow it before chewing well; wait till I get the flavor of it very well. In that way, you will have an opportunity to thank God for the food you are given. He is the One who not only gave you that apple, but also me, the organ that can taste it. This is just another amazing thing that makes your life beautiful! By thanking God, you will deepen your worship of Him.

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

I am placed inside your chest cavity as two air sacks-or bellows-surrounded by your muscles. I took my first breath right after birth and I still keep working non-stop. Even while you are sleeping, I fulfill my function with the automatic command I receive from the respiratory center at the back of your brain. My close friend Heart started working even before me while you were in the womb. I was resting then; actually I hadn’t even formed fully. As all your needs like food and oxygen were met in the body of your mother-whose heart you occasionally break-I didn’t have to make extra effort to get air, being filled and emptied. Even if I had attempted to do so, I would have had no chance of succeeding; since you were contained in the amniotic fluid, an attempt to breathe could have caused you to drown.

The first breath I take after birth is critical and rather difficult, since the windpipe is still much narrower than normal. On the other hand, the number of my alveoli where oxygen exchange with the capillaries is realized is so high in relation to body size that it balances the situation. When I make my first move and fill with air, I put pressure on the arteries and veins. Then the vessel directly connecting my artery to my mother’s aorta is dismissed, the curtain between the valves is closed and the blood circulations are separated. If this curtain is not properly closed and a gap remains in between, the oxygen-rich blood and the used-up blood mix and result in the disease known as cyanosis-or “blue baby” syndrome. As these two kinds of blood mix, the tissues are not supplied with sufficient oxygen and the white parts of the skin and eyes assume a bluish appearance.

Turning blue-purple due to lack of oxygen in the tissues is the same for smokers. Cigarettes-my archenemy-contain hundreds of toxic substances, such as carbon monoxide, which combine with the hemoglobin in blood and prevent oxygen transfer. Therefore, the lips of smokers turn slightly purple. You need to be careful with the air you inhale. The windpipe which brings air into me is covered with a ciliated epithelial tissue which catches the dust brought along and sweeps it outside. While you are asleep, the vibrating cilia of this sweeper work throughout the night and in the morning you get rid of the outcome of their propulsion by clearing your throat. However, every draw of a smoker kills 800–1,000 of our ciliated epithelial cells. After some time, they become unable to sweep the toxins (carbon, sulfur, lead, etc) inhaled with the air. I can’t stand it anymore! The increased air pollution is already putting enough strain on us… this habit is just too much for a lung to handle! It is just… an open invitation for cancer! Sorry, Peter, I didn’t mean to be rude. I appreciate that you don’t smoke, but I wish those who do would realize how splendid a mechanism they are destroying.

Now let me tell you about what a work of art I am. As you also know, art in a structure becomes more meaningful with functionality. As is the case with my other friends with which I work in your body, I am perfectly made to fulfill my duty. In other words, never mind forming an organ like me as a consequence of molecules and cells accidentally coming together, even a single protein molecule in my structure does not come to existence through unconscious causes.

With every breath you take, the pressure of the oxygen within the air inhaled rises, so it passes through my membranes by diffusion and into the adjacent capillaries; there it combines with hemoglobin molecules. At the same time, the carbon dioxide passes through the same membranes into me, and I dispose of it. Both of these are easier said than done! You breathe 13–14 times a minute and the whole thing is repeated over and over. As I keep expanding and contracting during breathing, which you are unaware of most of the time, first of all I need to be very flexible. Together with this flexibility, my most important quality is having the largest possible surface area within the smallest volume. My surface area of around 100m2 (as large as a tennis court) is made to fit into your chest cavity in the form of thin membranes so that my large surface allows gas diffusion. These membranes need to be kept wet; a special fluid is secreted as a precaution and respiration is realized smoothly. Without this fluid, my membranes would just stick together, unable to carry out their duty.

You can compare the course of the air inhaled to that of a car passing from a highway onto increasingly smaller roads and in the end reaching a dead end in the small sacks named alveoli. The air coming in through the mouth and nose unites at the expressway named the trachea, or the windpipe, which is 15cm long and 2–3cm in diameter. Incidentally, I have a couple of things to tell you about the way you breathe. As a matter of fact, inhaling is the duty of the nose. I’m sure it also has a lot to say as well, but let me just mention a simple fact about it. Now, you should inhale through your nose, so that the air you take in gets warm, wet, and is cleaned from dust. If you try to breathe this way, you do not trouble me much, and reduce the risk of catching a cold or an infection of upper respiratory system. Inhaling through the mouth helps dust and germs get into me and you might contract various illnesses from bronchitis to pneumonia. Now you know why kids who have adenoids who sleep with their mouth open get ill so easily. Sorry, I couldn’t help speaking on behalf on the nose.

Well, what were we talking about before that? Oh yes! The ways through which the inhaled air passes. As the name suggests, the windpipe which makes the air reach me is a cylindrical tube surrounded by 16–20 cartilaginous rings. As it is placed beside the esophagus, one side of the rings is made of soft cartilaginous tissue instead of hard, so that they don’t hinder swallowing. The muscular tissue near these rings helps them widen and narrow during respiration or coughing. I sometimes warn you by making you cough. Maybe it seems to be a disturbance, but if I don’t push out air by coughing through the contracted windpipe, contaminants can clog me up and cause you to suffocate. Therefore, the burst of air-what you call a cough-is a great blessing to you.

The sound system at the tip of the windpipe is another wonder. The used air I send out vibrates the cords in that voice-box and produces such melodies, gives voice to such speech! The air divides into the two lungs. My two sides are not symmetrical; the one on the right is divided into three, and the one on the left into two. I think this was meant to make room for the neighbor on the left, the heart. In addition, if there’s any cancer growth in me, the diseased part can be taken out by an operation and I can keep on functioning. God knows the wisdom behind this form. After that, these main bronchi separate into 8–10 thinner branches, like highways connecting to narrower roads. This branching resembles a tree turned upside down. At the tips of these thin branches are the respiratory bronchioles resembling clusters of grapes. The small spheres which make up the cluster are the end of the road and are the most vital parts. These spheres named alveoli are made of very thin membrane and they are surrounded by a net of capillaries (picture 5). These are the functional spots where gas exchange is realized.

I hang in the thorax with veins and arteries all around. There are two layers of protective membrane over me. One of them is stuck on me, whereas the other is stuck on the ribs which form the chest cavity. There is a fine and slippery fluid in between these two layers and it neutralizes the friction every time I inflate and deflate. If it hadn’t been placed there, I would wear out and be damaged. As I inflate during inhalation, the chest cavity should expand simultaneously to make space for me. If it weren’t given a flexible form, I would fail to breathe and you would eventually die. Fortunately, the protective set of ribs and their connection with the spine are flexible enough to make me work comfortably. In addition, the dome-shaped muscular partition (diaphragm) separating the thorax from the abdomen contracts and pushes down the organs in the abdomen. Thanks to the simultaneously programmed movement of both the ribs and the diaphragm I inflate with air and expand.

Being in constant contact with the outer environment makes me susceptible to various diseases. Coughing is among the foremost signals I give in the case of disease, and sometimes-excuse me-I produce a mixture of blood and phlegm. Also, I may have difficulty in breathing and warn you with chest pain. You should be alert to my signals. If bacteria and viruses infect me, they might reproduce inside my air sacs, and cause stiffening and suppuration.

I am particularly sensitive to allergic disorders. When the straight muscles on the walls of my bronchi contact an alien substance, pollens for instance, the consequent histamine secretion makes my muscles contract. In addition, allergic diseases, which can affect blood vessels, affect me a lot since I happen to be one of the major organs contributing to blood circulation. As a result of the contraction of my bronchial muscles and difficulty in disposing of the mucus I secrete to defend myself, I have trouble with breathing-you call it asthma.

In addition to this, we can mention diseases like emphysema, acute or chronic bronchitis as problems I frequently face. Even your anger has a great impact on me. Breathing becomes more difficult immediately.

Peter, I’m sorry, it is not possible to summarize a work of art like me within a few pages, but I need to stop now… but please, keep away from polluted areas and cigarette smoke! Send me as much fresh air as you can. And even though you mostly take me for granted, like my other teammates, please reflect upon what a blessing I am.

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

When you were a mere nineteen-day embryo, my creation began from a special mass of cells. At first, I looked like a tube, then I twisted, turned, and gradually the creation of my chambers and my neighboring veins began. Together with the other cells of the body, we developed to serve as different parts, such as nerves, skin, cartilage, muscles, and so on. And the cells which make me up are very specially programmed. When they reached a certain number and mass on your twenty-second day, they were commanded to march, and only God knows for how long. When all my cells contract together to beat, you feel it as your pulse. Though I operate in your body, Peter, you do not think much about my beats, but when you run fast, I just have to beat faster for your legs require more blood. Only then, Peter, do you notice me, but you do not give me a second thought anyway. You are so heedless, as if I will carry out this duty forever and will never get tired. Let us admit that is not so unusual for a young man, but the worst is you do not ever think of who blessed you with such a gift, and that really makes me sad. Nowadays you go to high school, and there they occasionally talk about me in biology lessons. Peter, you are not to blame, actually-teachers talk about me as if I were a simple pump. However, you cannot even move a finger if I do not pump blood into your brain. But today, I will let you know that I am not just a simple mass of flesh. I am going to tell you today that you should care about me both physically and spiritually, otherwise, you will truly regret it. I am just a friend, warning you about the bitter truth; you still have a chance to make it up.

All the cells, the building blocks of your body (maybe 100 trillion of them) need me for their nutrition, breathing, digestion, waste disposal, and to carry out their particular duties. You wonder why? Well, all their needs are met thanks to my being created to work ceaselessly. This is why I start working before any other organ at the embryonic stage. Even I do not know how long exactly I will work; sometimes, in spite of being in sound health, the appointed hour comes and I leave my duty obeying the divine command. For the most part, the Angel of Death does not tell me to stop for no reason-he somehow uses an apparent cause. There are so many causes to make me leave my duty, in such an age where accidents, bad habits, and suicides are tremendously high.

In fact, even I marvel at how I work. I am equipped with certain precautions against blood losses which occur as a result of injuries, but if the blood loss is not made up for and the bleeding is not stopped, I may get tired and stop functioning after a certain time. I can be easily affected by certain types of poisoning. This does not matter much, but what really upsets me is your living irregularly, unhealthy eating habits, inactivity, laziness, and especially your leading a stressful life quarrelling with everyone. I endure these for a while, but sometimes when I cannot take it anymore, I just quit or pretend to quit in order to draw your attention. Right after that, you have people screaming, calling the doctor in panic, demanding pills, adrenalin or heart massage… All of these are fine my dear, but why on earth do you wait until I become like that! Listen, Peter, I am telling you again, it is you who does me the greatest harm. So do not be offended if I one day get tired and quit! You just keep gulping down fatty foods, my downstairs neighbor, the stomach, keeps complaining that you are filling it up too much. When it is filled up, it starts putting pressure on me naturally. Haven’t you heard about the hadith counseling people to leave one third of their stomach empty and rise from the table before they are full? I can understand the vegetables, but what about the fast food, fried things, and other unhealthy stuff you eat? Be careful, you will have to pay for it before long, and it will be too late. Well, one has the right to benefit from the blessings in this world, but one should know where to stop. If you go on like that, my valves will be disabled by fat and my main arteries will be clogged. As for my coronary arteries, they are already created narrow and they can be clogged in a short time and lead to a heart failure.

You are just a couch potato lying before the TV all day without moving at all. I would not be surprised if you started going to the corner shop by car. If only you did exercise for a little part of the day. Some of your friends do the daily prayers and kill two birds with one stone. They fulfill their duty to their Creator and relieve their hearts with the bodily exercise. In addition, their hearts are at ease thanks to their faith. Another welcome relief for us is their fasting for a whole month once a year. Staying hungry for a certain part of the day comforts me and gives me a chance to burn some fats.

The muscle tissue which makes up my main structure is designed as an intricate ball of fibers and so I am able to function properly without changing my shape too much as I contract and relax. The surface of my walls is wrapped up in a double layer in order to prevent harm from rubbing against the ribs, which are set around me as a protective cage. Also, there is a special liquid between the two layers of the membrane and this lowers the friction even further. C’mon Peter! Who can arrange so many precautions so splendidly?

Like car engines with four cylinders, I also work like a pump with four chambers. My upper chambers are called atriums. The one on the right takes in the waste-rich venous blood, and the one on the left takes in the oxygen-rich arterial blood. The muscular strength of these chambers is relatively low, but it is good enough to pass the blood they take to the lower chambers. As for my lower chambers, named ventricles, they have thicker walls and stronger muscles. They are given the ability to contract and pump blood with great pressure. Moreover, the lower chamber on the left has even stronger muscles and thicker walls since this very chamber enables me to send blood to the entire body with great pressure and speed. Thanks to the large vein named the aorta, I send blood to each organ in the required amount and at the right speed. Precise timing is vital for my four chambers to contract successively, to open of the valves at the exact moment they should, and to send blood to the neighboring chamber or to the two main arteries. The closing of the valves also requires perfect timing to prevent the blood from flowing back. The coordination of this timing mechanism is obtained through the regular production of electricity by the atrioventricular bundle. If there is something wrong with the timing of my valves, or if they cannot close properly because they are blocked with fat or calcification and so let blood leak, you diagnose this situation as a disease. As a precaution against blood flowing backwards through the valves between the atriums and ventricles under heavy pressure, some cords are tightly fixed under them. You are not aware of any of these, but I keep working even when you are asleep. Naturally, I may change my speed at different times, according to what you do. While you are asleep, I work at an easier tempo. I work faster than normal while you are running or doing heavy exercise and I send the necessary amount of blood to every organ. My energy source? Well, the fuels I mostly make use of are fatty acids, lactic acid, and sugars. In addition, thanks to my special metabolism, I never get tired. There is only a very short period of rest of one tenth of a second between every contraction and relaxation I make. The stimulating command must come with perfect precision so that all my muscles start to contract and relax simultaneously and so that I can generate an efficient pumping force. Actually, I am not quite sure how this timing is arranged during different activities. A tiny automatic center on me produces electrical signals; the activities of upsetting and then resetting the ion balance inside and outside the cells in order to produce these signals is carried out with reactions happening in a time as short as one thousandth of a second. Even though these cells make me work with the electricity they produce, I am not really independent. The foremost among the factors that affects my functioning is the nerves from the brain. Therefore, the fear, anger, and sadness you experience upset my functioning as well. This must be why people have taken me as the center of emotions; although anger and sadness take place in the brain, I was located as the emotional center, as the effect surfaced in me.

Peter, I will ask you a simple question: is there some engineer who made the TV set you lie before? Are there people who write the articles in the magazine you are holding or who lay out the letters and pictures? There are some agents right? So, more perfectly than all of these, should there not be One who has created me and my system of blood vessels, and then placed me in your chest cavity? Well, it is high time you switched off that TV set. Now Peter, just as I fulfill my duty regularly to keep you alive, you should also spare just ten minutes to pray for and praise your Lord Who has created your body so perfectly. In the meantime, I will have found a chance to get rid of the strain you put me under because of your hurry and stress.

Within these few pages, I have probably told you only a thousandth of my splendid structure and the precision of my functioning. Neither I, nor physicians have the proper knowledge to explain all about me completely. So, my friend Peter, you need to learn to say, “How beautifully it has been made,” instead of “How beautiful it is.”