Circulation of the Blood Basics on Physiology

Allah has created Man in such a way that Knowledge is actually the study of Man only. If we study him on the spiritual level it certainly is a great knowledge and interestingly, subject of the Holy Book Quran is Man to whom it provides Guidance to better his life here and in the world after this one. Let us see here briefly how wonderful the working of our bodies is and try to understand its basic physiology well dealing with the subject in a concise manner. Although this subject is a vast one yet I would only touch the basics here in such a concise manner that we all may get a clear touch of knowledge in this regard and as such this writing is intended to guide a layman to working of the physique enabling him to understand what a work of art, harmony and perfection his body is. Due to this intention, I have tried my best to deliver the text in a simple form with a care that accuracy is not compromised even if an artistic touch influences the text at a few places.

To understand a Human Body, we need to understand Cell, Tissue, Organ and lastly different collections of Organs (systems of the Body) so that we might get a clear idea about Physiology (i.e. working of the Human Body). “Cell” is a very small unit of the body, seen by the microscope only. Take an egg to understand concept of a cell in the human body. Just as an egg has a yolk, the cell has a Nucleus that keeps the cell in such an order as to fulfil its duty well wherever it is located in the body, being a part of any tissue or organ so it’s a control area for the cell. Nucleus also takes an important part in management of the division of cell and it has Chromosomes that are based on D.N.A. which it transfers in the cell taking place by division thus transfering hereditary traits of the parent cell to the new cell. The area beyond the Nucleus is called “Cytoplasm” just as an egg has a white in it. This Cytoplasm has air, water, nutrients and chemicals that the cell has taken from blood of the body. It is enclosed by a thin membrane like an egg that gives way to useful things for survival to enter inside and useless things to exit outside through it well. Water is retained according to necessity giving the excess amout outside that is taken by the blood to dispose off by working of kidneys. If however the cell does not get rid of the excess amount of water, it may cause “edema”. The reason for such adverse functioning of the cell may be a fault in working of kidneys or even heart and so excess water has to be taken out and a very low intake of salt must be maintained for wherever salt goes, water has to follow. However, when water is lost much through diarrhea or any other disorder (mostly of intestines), intake of water and salt plus a touch of glucose must be maintained well specially in small children. To understand necessity of water in a human body consider the fact that a normal human body is based on nearly 70% of water and interestingly this is the same ratio that the water on Earth keeps with the land on Earth (the Holy Quran points out this similarity by presenting event of rain on land to revive a barren land in comparison to awakening of the dead on the day of Judgment). The research on the nucleus has gone so far that much of genetic features are understood by the study of DNA (Chromosomes) at the present times yet even though I do respect the efforts that are put into such research, I personally do have some reservation for this work due to Islamic moral values as some of the tasks performed through such research do challenge work of Allah by my viewpoint. As Muslims, we may have to sacrifice a few physical benefits for sake of a good spiritual development in the coming times as the matter stands.

Cells, when they gather at a place in a sequence for a specific task, form “Tissues”. These cells adapt to the work they are given and take care that the work assigned to them is done well with aid of other cells of the tissue. Cells in the eye let the light pass well while some of cells of the nervous system (Neurons) are longer than other cells. Some of the cells even produce chemicals that are necessary to sustain the body and work well in harmony with other cells while cells of the Wind-Pipe even form a mucus to perform their task well. They work with the help of “celia” (the small thin hair that they have) and with the mucus that is formed to keep away all harmful and un-necessary things away from the place. Cells of Digestive System not only make special chemicals to work on the eaten food but also are adept in helping to absorb the necessary items from the nutrients as they pass the small intestines. The Excretory System has cells that have much flexibility in them as to retain the urine uptil necessity and loosen themselves well at its disposal to keep their integrity intact. These tissues are found in the Body in four forms and these are Membranes, Connective Tissues, Nerve Tissues and three types of Muscles specially Myocardium (cardiac muscle) while other two types of Muscles are smooth (that are involunatry muscles) and skeletal (that are voluntary muscles). Sometimes even blood is termed as a Tissue as it has so many cells in it yet they are not fixed and this term is loosely used for it. “Organs” are collection of Tissues that keep to a specific task all the life and each organ with help of other organs of the body fulfills some important need for survival of the body uptil the appointed time of its death. Vital organs of the body are often protected by bones as their guard and they are well planted at their respectives sites to perform their respective duties wonderfully well. Mostly each of these vital organs is master of a system of the body and works in harmony with all the other organs well. Organs unite to form “Systems” of the body and study of these systems would enable us to understand the Human Body well. Blood is a part of every system and so Circulation of the Blood touches every system of the body well. However, as written, each System of the Body has a master organ with some other organs to help that master in its work and thus they collectively form a specific system of the Physique. The fact about Blood is that it is composed of Plasma (that occupies normally much more than a half of its volume and itself comprises of 90% water and a very high number of different types of proteins in the other 10% with many other nutrients and particles in the balance) and three corpuscles (formed elements) named Erythrocytes (red blood cells that have no nuclei with circulation life of some 120 days), Leukocytes (white blood cells with circulation life of less than a 12 hours) and Thrombocytes (“platelets” that help in clotting the blood that has many factors for its application, with a life of nearly a week). Function of the blood can be given in a sentence as "by its circulation, it takes care that all necessary items are transported TO all cells of the body for their use while all waste materials are transported FROM all cells of the body towards outside by help of vital organs of the body so that Homeostasis of the body remains intact". Note that when a tissue is injured, it releases a substance “thromboplastin”, that taking the help of some protein factors and calcium ions changes to “thrombin” and this is the process that needs platelets too for its function. This forms fibrin that are fine thread-like network and it forms a clot at the site stopping the blood to flow off in a great quantity that may cause shock. In a need for blood, transfusion of blood injecting other person’s blood in the patient is performed though a caution is taken that the blood groups of both do match. Actually, the blood of the patient may contain antibodies (attackers of anything that is foreign to the body, deadly to its homeostasis) and they may take substances known as “A & B” of the donor’s blood received, to be foreign so they would attack causing the blood to clump. That is why the better transfusion is among the persons of the same blood group though even then it has to be seen if the donor's blood is Positive or Negative so that the patient's blood if positive does not find the Negative factor in the donor's blood as antigen, attacking it then and there and vice versa. The point to note is that there is an Rh-factor in the blood too that must be taken into account as mostly this protein Rh is present there thus the name Positive is applied to such people that have this factor in their blood yet a few do not have this factor and they are termed as Negative. Positive and Negative do not go well together in blood transfusion so it is necessary to take care in this regard too. Coming to number of systems in the body, these systems are taken to be nine, ten or eleven or even more and this difference of opinion is due to the fact that sometimes a single system is distributed into two parts or more thus counting a single system twice or thrice. Let us see these systems that are taken as Nine Systems here in this writing to understand basic working of Physique in a concise manner, first naming them and then studying them one by one in detail.

The first system of these is the “Respiratory System” that is related to the intake of Oxygen giving away Carbon-dioxide as Cells of a human body need fresh Oxygen to go on performing their functions well and that they take from the Blood that holds it in its Red Cells (and Blood gets it at the lungs giving away Carbon-dioxide there). The second system of these is the “Digestive System” that is related to transfer of the needed nutrients to cells of a human body which the blood holds taking it from what a person eats and drinks and then giving it to cells of the body. The third system of these is the “Excretory System” that is related to disposal of un-necessary and even harmful items from the blood that has received them from cells of the body thus clearing the body from things that may affect it totally adversely for sure if retained in the body. The fourth system of these is the “Reproductive System” that is related to growth of the number of human beings so through it the life goes on and blood is related even to this system as a smooth flow of blood is necessary to genitals for a smooth working of this system. The fifth system of these is the “Nervous System” that is related to keeping an integrity in working of all the organs of the body by taking messages to & fro from the Brain that needs blood to evaluate status of the body all the time. The sixth system of these is the “Endocrine System” that is related to deliver messages from places to places with assistance of the blood taking care that uniform status of the body remains intact. The seventh system of these is the “Immune System” that defenses the body mostly by function of white cells in the blood from all such bodies that influence the Body-Works adversely so that they may not find way into the body and if they do, they may not remain harmful in any way to the body for sure. The eighth system of these is the “Skeleton System” that is related to keeping posture of the body intact, to protecting the organs having a great importance and to providing the blood with important cells initially by function of its marrow well. The ninth system of these is the “Sensory System” that is related to five senses of Vision, Hearing, Taste, Smell and Feelings that, though directly dependent on the Nervous System, does have a unique status keeping itself strong by touch of the blood it gets for its functions in the body. These are nine systems of the body each having a master organ that rules to keep performance of the system well with the last system having five masters as it is collection of five systems within one system of the body. There is a Tenth System too that works with these Nine and it not only has a physiological touch but also a spiritual side to it. This is the “System of Psyche” that is related to the hereditary values one receives, influence of the environment one lives in and the thought regarding one’s own self that is established by faith one keeps having a great effect on the body thus making one capable of achievements or losses according to one’s development of mind. Its master organ is whole of the brain with a special emphasis on the spinal cord. As there are these nine plus one systems present in a Human Body there are 14 master parts in all, each a master of one system. The excess is due to the fact that the ninth system has 5 masters while the others have one each though that one part may be present in a pair in the body like kidneys that are masters of Excretroy System. Here, I would keep to study of nine systems of the body keeping the psychological study aside for sake of convenience in study of the human physiology.

There is a very interesting point to note in physiological study of the Human Body and that is called “Homeostasis”. There are many aspects to this one word as used in Physiology and all imply that the human body keeps its status at a specific nature. In other words, Homeostasis means that the body keeps its temperature, its rate of heart beat, respiration, body fluids etc. within specific limit thus keeping the body at a specific nature never running away from this assigned status as a high deviation would certainly cause its death that it avoids at all times and places until the end seems inevitable. The study of Physiology is much easier if this important point is always kept in view and in fact there is a natural spiritual status of a person too as everyone does recognize the Truth at heart and any deviation from that concept puts a person into some tension for sure.

(1) The Respiratory System needs circulation of the blood and working of the heart to apply itself well in the human body. The blood circulates the whole body but its circulation is one way only though it may be going away from the heart with fresh oxygen to provide through arteries branching from aorta or coming towards the heart with a high amount of carbon di-oxide by the veins. It is necessary for the body to keep this circulation going on well by a physical force as blood takes oxygen, nutrients, guidance etc. to each part of the body taking its waste particles thus assuring that it does funtion well and it is rightly said that the blood takes everything everywhere in the body. This force is provided by the heart, master of the Respiratory System, with a normal beating of about seventy strokes per minute as circulation of the blood is a prerequisite for this system to operate well. The heart is located between lungs at middle of the chest (bit towards the left) and it works well with aid of our lungs at which the de-oxygenated blood gives carbon di-oxide and takes oxygen that has come to it with the air that we breathe in. The heart has two sections and each again has two sections thus the heart has four sections in total, two atriums and two ventricles. Each section has an upper part (atrium) that receives the blood and then provides the same to its lower part (ventricle) with a valve located in between each so as to stop the blood to return to atrium. Valves are also present at the exit of the blood from the ventricles making them four in total. The basic two sections each having its atrium and ventricle, are separate from each other by a partition (septum) in between and the blood can not reach directly from the right section to the left section except by flowing through the lungs. The blood that is present just above six litres in a normal person weighing some 72 Kilograms, circulates the heart first (not all of it at one time of course) before circulating the whole body and this inner circulation makes sure that the de-oxygenated blood gives away carbon di-oxide and takes up fresh oxygen at the lungs to provide the same to each cell of the body. The blood starts its circulation in the body when the left ventricle, the lower part of the left section pumps up the dark red oxygenated blood powerfully inside the aorta (the main blood vessel that basically takes the oxygenated blood and then distributes it by its branches all over the body). This ejection of blood is so poweful up the aorta that if the aorta would have been opened at this site it would have gushed out four to five feet up. Aorta takes care that all the cells of the body receive their due share from the oxygen held by the blood in its red cells by forming a network of arteries (the important ones named for the organ they supply blood to) in the whole body that reach the remotest tissue of the body changing to capillaries (very thin tiny blood vessels) touching all parts well. Taking the Carbon di-oxide that the cells exchange with Oxygen to burn for their survival, the blood returns by veins (important ones again named for the part they receive blood from and mostly they run parallel to their respective arteries though much nearer to the skin) to the heart, dropping into two big veins that open into the right atrium of the heart dropping the de-oxygenated blood there to be processed ahead. These two big veins are named as “Superior Vena Cava”, that collects the blood from all the areas upper to heart in the body i.e. head, neck, upper extremities and even the chest, and “Inferior Vena Cava”, that collects the blood from all areas lower to heart in the body and so its much longer and its collection is somewhat complicated than the former. Note here that blood operates by two main sets of vessels that is “arteries” that distribute the oxygenated blood among cells taken at the lungs and “veins” that transport the deoxygenated blood to the heart so as to give Carbon dioxide and take up Oxygen at the lungs in exchange. By contraction of atriums while the ventricles relax, the blood fills into respective ventricles and then as the atriums relax collecting the blood inside, the ventricles contract to forward the blood into the lungs and into the aorta respectively and this process creates the beating voice of Lubb Dupp. The lungs are very light due to the air they hold in them and they are the place where exchange of gases takes place as it is in direct contact with the flowing air outside the body that enters here via nasal cavities, trachea (the wind-pipe that has its opening at the pharynx, the space at the back of the mouth where the voice box “larynx” is also located with its protruding Adam’s apple) and two Bronchi (the last part of trachea and it’s a division of trachea that supply blood to sacs of both lungs well). There are two lungs set side by side in the thoracic cavity that have millions of sac-like structures known as alveoli that receive air with better Oxygen from the bronchioles, the smallest branches of the bronchial tree, to exchange with Carbon dioxide in the blood. As the lungs receive the deoxygenated blood from the right ventricle, the sacs in the lungs that hold fresh air with a better quantity of Oxygen and the blood that is held by the capillaries with a lesser quantity of the same exchange the gases, blood in the vessels taking Oxygen from the air and air in the alveoli taking Carbon dioxide from the blood, by a process named as Diffusion of gases. Diffusion is a process that means the uniform spread of gases when in touch at a closed place so both blood and air take the gas that is lower in concentration at their site respectively. Note here that the both respective containers alveoli and capillaries have a very thin barrier in between that does not stop their direct contact though it does stop the blood to break away. This oxygenated blood advances to the left atrium that gives it entrance to the left ventricle and the left ventricle pushes the oxygenated blood with an amazingly powerful force into the aorta and so the cycle goes on until end of the physical life.

(2) The Digestive System comprises of the mouth, esophagus, stomach, intestines, pancreas, gallbladder and liver (the master organ in this system). Blood takes up (absorbs) the nutrients from intestines to provide them to the entire body. However, as the cells do not accept nutrients just as we take them in, a few enzymes of the body convert them to a status without being the part of the reaction that takes place by their action where cells may accept them for their metabolism (biological processes of taking up energy from the matter). Conversion of the nutrients is named as “Digestion” and the taking up of these nutrients by the blood is called “Absorption”. This means that there are two processes that apply in sequence (rather three if we consider the point that Digestion completes in two phases) so that all the cells may get their due share from the food taken in without any trouble. There are six types of components in the food that we eat and that are the basic need of the body. These six are Carbohydrates, Proteins, Lipids (Fats), Vitamins, Mineral Salts and Water. Note here that Water is acceptable to the body in its natural state while Mineral Salts dissolve in water so there is no need for the body to apply the process of Digestion to these two. Also some of vitamins dissolve in Water while the others are taken up by Lipids so it also does not need individual attention in the process of digestion but the other three i.e. Carbohydrates, Proteins and Lipids do need this process before absorption. It is interesting to note that there are three body fluids each applying in the body at its own site on each of these three to convert them to the acceptable state for the second phase of Digestion and then there is the pancreatic juice that applies to form the second phase of Digestion thus converting the nutrients well for the process of Absorption. The first phase of digestion starts at the mouth and as we take the food in, the saliva in the mouth while softening it so as to swallow easily, works on the Carbohydrates by an enzyme “ptyalin” preparing it for the second phase of Digestion. Enzymes do not become a part of process of digestion but work to initiate and apply the process well. This preparation changes some of starches into sugar. When this eaten food reaches the stomach via esophagus (the tube connecting mouth to the stomach nearly 23 cm long), it is worked upon by the gastric juice specially by an enzyme “pepsin” that is activated by Hydrochloric Acid at the place and targets all types of Proteins specially for digestion to prepare them all for the second phase and the process of Absorption. Hydrochloric Acid also softens the connective tissues in the meat and kills bacteria that have come at the place. Stomach has many folds in its lining if empty yet when it dilates to hold food and liquid, these folds disappear making ample space at the place. It has a valve “pyloric sphincter” where it meets the small intestine that prevents unprocessed food to enter and also takes care that the processed food does not enter in large quantity in the intestine. Thus food converts to the form of “chyme” here that is a semi-liquid substance that can enter the small intestine in small quantities in sequence. Now only fats remain to be processed for their prepartion for the second phase of digestion and the chyme has to enter the small intestines from the stomach now where the second phase and the process of Absorption would take place. Just as some amount of the chyme enters the duodenum (the first part of the small intestine), it is mixed with greenish yellow bile that is delivered from the liver via gallbladder through the common bile duct to this place. Bile works here on the fats breaking them totally to prepare them and in this way the first phase of Digestion is somewhat complete though the final touch to this process is given in the second phase by the pancreatic juice that enters the small intestine just before beginning of the process of Absorption. Bile also sees that the food does not stink or gets to a state where it is incapable of being absorbed by the blood. Although the small intestine is longer than the large intestine in length (some twenty feet without folds in comparison to five feet of the latter), it is named so because of a smaller diameter with a high surface area due to its protruding villi (projecting shape of its surface). These villi help the blood take up all the digested nutrients well (that move on in the small intestine by a wavelike action of involuntary muscle layers known as Peristalsis) to transport them all over the body. The second part of the small intestine is jejunum and the last one is ileum where it joins the large intestine. A muscular ring “ileocecal valve” is present here that gives way to it to enter in a small pouch like structure at the beginning with a small tube attached called “vermiform appendix”. This meeting of the intestines occur at the lower part of the abdomen to the right side where the large intestine ascends and this part of it is named “ascending colon”. The second part that runs somewhat below the liver, pancreas, stomach and other organs horizontally is termed “transverse colon”, the third part where it descends at the left side of the abdomen is called “descending colon” while the fourth is “sigmoid colon” that just angles at left lower abdomen to the posterior part to form last part of the large intestine that is called “rectum” which leads the waste material to the opening named “anus”. Thus the alimentary canal (the way the nutrients travel) is the passageway that starts at the mouth ending at anus giving all the necessary food and liquid items to the blood to transport all over the body and expelling all waste products from the body to keep it clear of their adverse effects. Now, as for the second phase of digestion, it needs the Pancreatic Juice that has three special enzymes each one targeting one of the nutrients that need the process of digestion for their absorption. These three that apply at the small intestines are “Lipase” that works on processed Lipids (Fats) converting them to glycerol and fatty acids that are readily taken up by the lymphatic vessels, “Trypsin” that works on processed Proteins to convert them to amino acids that are readily absorbed by the blood and “Amylase” that works on processed Carbohydrates with an aid of a few other particles to change them all to simpler forms of sugar that are maltase, sucrase and lactase that again are readily absorbed by the blood. The blood by the aid of villi that has minute vessels of blood in them, takes up all the constituents of the food materials that the body needs at the small intestines with an exception of most fats that take an alternate path to enter the blood. This path is via lymphatic vessels that are also present in the villi and their main work is to form lymphocytes (special white cells) of the blood that we would study later on in this writing if Allah wills. The waste materials pass on slowly by the action of involuntary muscle in the large intestine towards anus and nothing is absorbed except for water here though vitamin K and B is also produced by the action of bacteria. The liver that I have mentioned as the master of this system was referred to only occasionally uptil now in the detail for this system yet it has a very important function to play. Liver can store glucose in the form of glycogen and if the blood needs sugar it can provide the same by converting this into glucose again putting it into the bloodstream. It also forms a few important proteins that are needed in the blood plasma including a protein that aids in the clotting of blood when an injury takes place so as to stop the blood from flowing away much with the aid of platelets in the plasma. Then it also functions to convert the fats into more usable forms in the body while as mentioned before, it also manufactures bile to aid in the digestion of fats. It also forms Heparin that is a substance that aids in prevention of clotting of blood so its interesting that it provides for the clotting of blood when needed and it also provides for the prevention of it when needed in the body. However, its most important function saving the release of heat being a naturally wonderful thermostat for the body due to its many functions, is to perform a check on all the nutrients that have entered the blood at the intestine and it only allows those food substances to pass on that are favourable or neutral to the body and not harmful in any way. This implies that the blood after taking the nutrients at the villi comes to liver first and for this a special route is provided to the blood in the body by name of Portal Vein. So the liver has double blood supply, one through the artery and other through the Portal Vein. The blood leaves the site through the hepatic vein that empties all the blood into “inferior vena cava” that leads it to heart. The Portal System of Veins does have the vein from the small intestine but it also comprises of the veins that come from the spleen, stomach and pancreas that are also present at this site of abdomen in front so the blood that has exchanged Oxygen for Carbon dioxide there, also runs through this Portal Vein. It is interesting to note that we are saved much by the function of liver when we err in the intake of edibles and in other words the adverse effect of drugs and diet is well-encountered by the liver and it also takes care that as it processes the adverse substances, their converted form is released into the bile to discard away from the body (this is not taken by the blood at the intestines). By research, it has been established that three types of diet have their special effects if regularly taken. Among them, one is the Diet for Protection (that includes green vegetables, juicy fruits, vitamins and salts and a fine intake of water) that is good to keep one active even in the old age and to control obesity, second is the Diet for Growth (that includes a high intake of Proteins again with a fine intake of water) that helps to grow when young and aids in fighting injuries well while the third is the Diet for Heat Retention (that includes a fine intake of carbohydrates and fats again with a fine intake of water) that helps those who are much involved in manual works full of much activity so each type of diet has its benefits and may be taken as the situation asks for. Liver has a small organ by its side that is a muscular sac by the name of Gallbladder for the storage of the bile it manufactures.

(3) The Excretory System takes care to eliminate waste products from the blood and as such, it removes them from the body. Though the respiratory system and the digestive system also eliminate a few waste products (Carbon dioxide with some water and bile plus residue from digestion with some water respectively) from the body as we have seen, the Excretory System that is taken as a separate system of the body manages the elimination of waste items by the function of Kidneys, the masters of this system. Kidneys, the bean shaped organs, work to make urine that comprises of the waste items excreting it to the bladder that eliminates the same occasionally and that is why the Excretory System is also termed as the Urinary System. The main parts of this system include the two kidneys that are located at the back in the upper abdomen but behind the peritoneum (the membrane that covers most of the abdominal organs as their apron and in addition forms a layer separating the kidneys from other organs that are in front of it in the abdomen), two ureters each belonging to one kidney that take the secretion from their respective kidney to a single urinary bladder opening at that sac from left and right sides, the urinary bladder that is the reservoir for the urine coming to it through ureters from the kidneys and a single urethra that conducts urine from the bladder to the outside of the body. Each Kidney has nearly a million nephrons that are coiled tubes, each having a bulb at its end named Bowman’s capsule. The bulb surrounds glomerulus that are cluster of capillaries where the blood rotates so that the nephrons may take up what it finds appropriate from the blood to decide the wastage. The coiled portion of the nephron that leads from the Bowman’s capsule is called proximal convoluted tubule and the coiled portion at the other end is called distal convoluted tubule that empties into a collecting duct that takes the secretion to the renal pelvis, a funnel shaped basin that forms upper part of the ureter. The middle portion of the nephron is termed as the loop of Henle. As the blood comes to glomerulus entering the bulb rapidly, nephron takes all that it can squeeze out of it leaving its main components with protein molecules intact as membranes of glomerulus do not permit them to leave the blood (size does matter even in the Human Body). This filterate comprises of both useful and useless components as it has amino acids, salts, glucose, water etc. with urea (the end product that is formed by the use of amino acids by the cells and that contains Nitrogen) and as it moves on inside the nephron, the proximal convoluted tubule takes the useful material from it keeping only the ratio needed to send with waste material and puts it into the tissue fluid where the blood takes it up again by reabsorption. This is a wonderful process that takes care that only the waste products are eliminated and no other. If the original filterate is sent for elimination, the balance of the blood and as such the whole body, would end as it would cause a fatal blow to the Homoestasis but as the Heart does not err in its function and as the Liver does not deviate from its defined work, the Kidneys also take care about the function of eliminating only the waste products from the body and not any needed substance for sure. Thus, deciding fast what is needed and in how much quantity by the information received by hormones, secretion of endocrine glands, it works well to give the needed components to the blood in the needed ratio and to keep the composition of the blood at a static position thus keeping the homeostasis of the whole body at a required position. The function of Kidneys maintain the balance of salt and water in the body (excreting them only in the required quantity adjusting well to the day to day necessity though the intake of water may vary day to day) and in other words, it maintains the balance of acid and base in the body (these two produce salt and water by Neutralization). Kidneys also make a few hormones specially renin that regulates the blood pressure, increasing it when needed. As for the Ureters they are slender muscular tubes that stretch out from the kidney basin to the urinary bladder, each one nearly one foot in length, passing behind the peritoneum. Each one enters the urinary bladder from its respective side obliquely so that the content could not return though the bladder may be full. The Urinary Bladder is below the peritoneum normally though when full, it may push the peritoneum up. It serves as a temporary reservoir for the urine and has the ability to hold about 475 ml of urine. Near its outlet, muscles form an “internal sphincter” by contraction of fibres and so the emptying of bladder is not automatic but voluntary (though in infants there is a reflex action for emptying the bladder that they learn to control as they grow up). The Urethra is the tube that extends from the bladder to outside so the urine is passed to outside through it eliminating the waste products of the body. This part is much longer in physique of a male as it is also a part of reproduction in them so it serves in two manners that is draining the bladder and conveying the sex cells while this part in a female only serves to drain the bladder, passing the urine outside through an opening in lower part of the vaginal wall. Urine consists of 95% water with Nitrogenous waste, salts and yellow pigment of bile dissolved in it. If glucose, albumin (a form of protein), blood or pus cells are found in urine, each indicates a specific disease in the body and so the examination of urine in addition to blood is useful to detect many types of diseases accurately.

(4) The Reproductive System is responsible to maintain continuance the human life and like all systems of the body is amazingly wonderful indeed. The primary organ for the male in this system is a pair of testes and for the female is a pair of ovaries, both parts being the masters of this system in the sexes respectively. In the male, the system mainly comprises of testes (located in the scrotum that form spermatozoa), vas deferens (an extension of epididymis), seminal vesicles and the penis while in the female, the counterparts are ovaries (that form the ova to send ahead), fallopian tubes, the uterus and the vagina respectively. It is interesting to note that much of physique of the female is concerned with this important task of multiplication of human beings thus it seems to be a central matter of life for her while body of the male as it is built, tells us that it is just another matter for him to deal with in life. This implies that much of the psychological needs are also fulfilled by marriage for the female in addition to biological needs quite well. The male sex cells spermatozoa are prepared outside the body proper in a sac that is called scrotum by the activity of the testes that are nearly two inches in length and nearly one inch by one inch in width and height respectively. It is interesting to note that this sac needs to be outside the body as the temperature inside the body is much hostile to spermatozoa. Each testicle contains a network of tiny coiled tubules that produce spermatozoa and gives them all to its respective epididymis (two highly coiled tubes each surrounding the upper part of each of the testes that may stretch out to 20 feet without folds as a thin thread and they are located in the scrotum itself except for vas deferens in a compact form). The epididymis stores the spermatozoa nourishing them to become motile and then extends upward in a straighter form (and this straighter form is named as vas deferens) each joining the seminal vesicle at its own side. Seminal vesicles collect the spermatazoa from the vas deferens and strengthen them by their own secretion that forms a large part of the seminal fluid at its expulsion. These are connected to urethra by ducts for ejaculation (and these ducts are actually the extension of vas deferens itself as it continues ahead taking it as a temporary station for some rest) and in these ducts, the single small prostate gland that lies just below the urinary bladder gives its alkaline secretion too to aid in the motility of the spermatozoa by a small passage. This extension now joins the single urethra that has a pair of tiny sac-like formations in the beginning named as Cowper’s glands that form mucus to lubricate urethra. Now, from here the spermatozoa pass on to the female organ at the time of copulation that takes place with an erection of the penis to force them inside the vagina. The legitimate sexual act between a married couple not only gives a physical relaxation but it also fulfils a psychological demand if you consider the point that the male has an aspect of force inside him that may find a wrong outlet to destroy the peace around leading towards criminal attitude in absence of the valid sexual relationship while the female has an aspect of charm that must be appreciated to keep her away from taking up negative means to display her beauty for the sake of appreciation that the valid sexual act provides well. As for the female reproductive system, the ovaries that are located at each side of the uterus, form ova, the female sex cells (singular “ovum”), in follicles that are small sacs in the ovaries. Usually one ovum only is released at a time. As it ripens, the sac tears off that eventually changes itself to corpeus luteum (a yellow mass that produces estrogens that is the female hormone, and progesterone that is the hormone for pregnancy) and the ovum travels to the uterus via its respective fallopian tube that is also named as the oviduct. Although the fallopian tube is not in direct contact with its respective ovary yet the ovum is swept into it by the current caused by the peritoneal fluid. Ova are present in the female from her birth in contrast to the production of spermatozoa in the male and they ripen about a thousand per month in one of the ovaries alternately. These ova decrease to four hundred thousand in number at puberty (in contrast, millions of spermatozoa are present at just one average ejaculation) and as about one thousand of them ripens each month in the follicles, a time comes around late forties where the female does not remain capable of reproductive activity any more naturally. Ovum stays here in its respecive tube for some five days though the tube is a tiny one yet due to the fact that ovum is stationary in contrast to the spermatozoon that is motile, it takes this time here moving slowly by some action of celia and some peristalsis in the fallopian tube. This fact seems to be conveying the soft and cool nature of the female waiting for betterment while the male seems to have an adventurous nature that needs to make its way even in adverse situations he has to face. Please note that the male and female respective masters of reproductive system do make the respective male and female hormones too that affect the respective bodies in the way appropriate. The fallopian tubes lead to uterus, the structure that holds the fetus until it is ready for birth. It is a muscular organ that is about seven and a half cm in length, five cm in width and two and a half cm in depth. Its lining is known as endometrium that sheds blood in menstruation when the ovum is not fertilized by a spermatozoon or a fertilized cell fails to attach to it properly in time. This bleeding period may vary from 3 to 6 days in different women all being normal while the menstrual cycle is the time period in between the menstruation and though it is considered about a lunar month normally yet it may vary from twenty-four days to forty-two days in different women all being normal. Menstruation depends on the hormones produced by the ovaries and pituitary gland also has a say in this matter. Estrogens that are in abundance at that time, start the preparation of the endometruim for a possible pregnancy. With its increase the hormone that stimulates follicle decreases and a pituitary hormone that transforms follicle to corpus luteum increases sharply. The effect of Estrogens & Progesterons thickens the endometrium as the ovum journeys to the uterus but if it is not fertilized then as it reaches the uterus, it disintegrates at that time. Some fourteen days after ovulation, corpus luteum decreases its secretions of hormones sharply and as the growth of endometrum depends on these hormones, it in turn degenerates with time and small hemorrhages appear in this lining. The blood flows out known as menstruation and bits of endometrium accompany this flow of blood, its duration being often 3 to 6 days. Before the next ovulation, the endometrium repairs itself so that the cycle may have its beginning again. The uterus has its opening in vagina, a tube some 7 to 8 cm in length that takes the lower part of the uterus (cervix) in the shape of a circular recess. Its lining has folds that have the ability to enlarge much at childbirth and this part also receives the penis in the sexual intercourse, taking the spermatozoa inside the body. These spermatozoa travel towards the uterus and often towards the ripe ovum in the fallopian tubes through it and mostly a female cell is fertilized at one of the tubes. Although only one of the spermatozoa fertilizes an ovum yet the enormous quantity of them is necessary to affect the ovum emphatically and to penetrate inside it taking an advantage swiftly of the awe that this huge number creates for it. The female cell closes entrance to all other male cells once it is fertilized changing into Zygote while the ovaries work on to create hormones that may aid in the pregnancy ahead. The fertilized cell goes on multiplying itself from one to two and from two to four cells and so on swiftly and as it reaches the uterus, attaches itself to the wall of the uterus changing into embryo and from here begins its growth. The embryonic cells now extend to the wall of the uterus and grip the maternal blood vessels. The last part of this outward projection eventually changes its form to placenta, a small flat circular organ that has a network of blood passages that allows exchange of items well for necessity upto necessity. The devoleping embryo consolidates its connection with placenta by gathering the extension that remains between itself and the placenta in a formation of a cord named umbilical cord having two arteries and one vein, and so placenta becomes a station that gathers blood from the mother’s blood stream and from it, gives all necessary items to the developing embryo by the umbilical cord taking away its wastage through the same route. The embryo encloses itself with a sac named amniotic sac that also takes its shape by the same extension of cells that the embryo projects outwards. It may happen that two different female cells are fertilized at the same time and place by two different male cells and both attach at the wall of the uterus thus establishing themselves as fraternal twins each having their own system of placenta, umbilical cord and amniotic sac and it may also happen that one female cell is fertilized by one male cell yet they split into two units in the very beginning of conception and each goes on to multiply by its own to form its own identity attaching at the wall of the uterus thus establishing themselves as identical twins of same sex both benefiting by the same amniotic sac and placenta though having their own umbilical cord. At this time, the formation of estrogens and progesterone increases much in the body to maintain and nourish the pregnancy by the activity of corpus luteum that normally decimates to a scar tissue yet if the pregnancy occurs, it goes on to form both the hormones without stopping at any time. In third month of the pregnancy, the placenta is able to secrete enough amount of both the hormones to strenghten the pregnancy by its own self. It is interesting to note that the first organs to develop are the heart, the brain and circulation of the blood as these three are so important in the body and if a serious damage to any one occurs (and mostly it adversely affects the other two), physical life of a person constricts much in activity if not ends at that time. Note here that the cells of Myocardium and of Brain once damaged are not formed again and their activity has to be taken up by other nearby cells of the same nature if the body has to survive. From the third month onwards, the developing pregnancy is called fetus and by this time it is totally recognizable as a human being. At end of the pregnancy at about 275 days after conception, the length of the fetus normally is 45 cm to 54 cm and the weight varies from about 3 kg to 5 kg. During all this time, all vital organs of the mother function more than usual caring about the needs of the pregnancy totally well in every way. When the time becomes ripe for the delivery, contractions at the uterus take place, a process that starts at the instruction of oxytocin that is a hormone formed by the pituitary gland, and these go on to expel the child through vagina to the outside with such powerful force that is unmatched in the works of human body saving the force of the left ventricle when it pumps the blood in aorta. Following birth, the “afterbirth” is also expelled via same route that includes placenta, amniotic sac and umbilical cord as their task has been done well. In this way an individual arrives to the world to grow on its own though by aid of his fellow beings, until the time of his physical death.

(5) The Nervous System serves to respond to the body’s internal and external conditions in such a manner that Homeostasis remains intact. Anatomically, this system is divided into two parts that are central nervous system (CNS, including the brain and the spinal cord) and peripheral nervous system (PNS, including the nerves that carry impulses to & from the brain and the spinal cord). Most of the nerve tissue is present in the structure of these two systems while a large portion of the latter system is divided into two parts again from a physiological approach namely “sympathetic” and “parasympathetic”. The nerve-cell that is called neuron comprises of the cell-body that contains nucleus and the fibers that are thread-like projections of its cytoplasm having two kinds namely “dendrites” that conduct impulses to the cell-body and “axons” that conduct impulses away from the cell-body. A thin sheath covers each neuron that aids in its repair in the event of damage. The neurons of sensory organs have dendrites that are much longer than the dendrites of other neurons while they also don’t have a tree-like appearance here as they have in other neurons and they also have a special receptor to note the beginning of the sensory impulse. The neurons though separate from each other are able to transmit their impulses to each other as these impulses leap ahead by the aid of “synapse”, the point between ends of the neurons that allow conduction to pass on by action of chemicals called nurotransmitters. In contrast to nerve-cell, a bundle of nerve fibers outside the CNS is named as a “nerve” while a bundle of nerve fibers that is located in the spinal cord is named as “tracts” that serve as cables that conduct impulses to and from the brain. Group of nerve fibers that send impulses to the brain and the cord are called afferent nerves and those that carry impulses to the muscles and glands are called efferent nerves. The Brain is covered by skull and it occupies the whole of cranial cavity. It is divided into three parts that are “cerebrum”, “brainstem” and “cerebellum” and these three are further divided into three parts each. The cerebrum (with its fissures that give it its shape and it is the master of this system) and cerebellum (the little brain) have a middle portion and two hemispheres while the brainstem has midbrain, pons and medulla-oblongata as its parts. The cerebellum is at the back of the cerebral hemispheres and it is connected with cerebrum, brainstem and spinal cord through pons that is in touch with all parts. Cerebellum works to keep balance of the body intact working for co-ordination in the use of voluntary muscles and a simple example where its application is at peak is the act of walking where the actions are put in sequence so that the balance is not affected adversely. It also sees to some necessary involuntary actions that the body has to perform well with the aid of brainstem that also cares for the necessary involuntary actions (like ear and eye reflexes by the aid of midbrain or reflex actions in respiration by the aid of pons or regulating the heart-beat and affecting smooth muscles of arteries by the aid of medulla-oblongata). For practical study the cerebrum is divided into four areas, each corresponding much to specific activities that a person undertakes controlling the behaviour in co-ordination with each other. These four practical divisions are frontal lobe (area in the the front related much to actions, left side guiding the right of the body and right side guiding the left of the body), parietal lobe (area just at center and behind it related much to feelings from the skin and to getting an idea of the distance, shape and size of a thing in contact by sight or feeling), temporal lobe (area below the frontal and parietal lobe related much to auditory and olfatory senses) and occipetal lobe (area at the back just above the cerebellum related much to sense of vision). A normal action needs co-ordination among the lobes well and the brain soon develops in very early years of life to co-ordinate the areas well for any of such actions. For instance in a conversation, it needs the temporal area to hear and interpret the heard speech and the frontal area to express the words of our own speech as we need to say due to its good control over muscles of tongue and larynx, the voice box. The parietal area works to understand the distance and shape of a person in address or an object while the occipetal area interprets the words it sees to language by co-ordination of other areas thus providing a skill to read and write the same. The Brain works for each action in this manner even taking the help of cerebellum and brainstem whenever and wherever necessary. Inside the central section of the brain, there is “interbrain” that contains thalamus and hypothalamus. Thalamus guides the impulses to their respective areas almost all of which pass through this part while Hypothalamus helps to control body temperature, water balance, sleep etc. and as such has a very important role to play in the homostasis of the body. Both sympathetic and parasympathetic divisions of the autonomic nervous system are under its effect. Parasympathetic part of the involuntary or autonomic system works automatically to keep the functions of the body intact by the help of myocardium and involuntary muscles. Sympathetic part of the involuntary system works automatically too but with an acceleration in the same functions that the parasympathetic system performs normally and it is much affected by the nerves at spinal cord too in addition to the command of Hypothalamus. It takes charge at “fight or flight” occasions working in adjustment with the hormone (endocrine) system. This change of effect in the body helps maintain the homeostasis of the body well and uses the available resources specially provided by the liver to maximum benefit of the body. In contrast to both these parts of involuntary system of nerves, the voluntary part applies by the help of skeleton muscles that have two or more attachments with one attachment each side at the bony joints. One side of these attachments is fixed (origin) while the other moves freely (insertion) that responds to the impulse coming into action (creating movement as required by creating a change in the size of the muscle or just increasing the tension in the muscle as in pushing against a brick wall). Thus, we are able to move hands and feet though the upper portion of both the parts are much fixed except where again such a joint is present. As for the spinal cord that is some 18 inches long, its location is at the back in the protection of vertebral column that is a series of irregularly shaped bones, 26 in total. Its main function is to perform reflex activities that need to be taken immediately because of adverse effect of natural sources of affliction to save the Homeostasis of the body. A good example is the immediate removal of hands from a hot substance that may suddenly and unknowingly come in touch with hands while Knee-jerk is also caused by stimulation at the spinal cord. Its other function involves providing a clear pathway to nerves to and from the brain and it occupies such importance in this transport that the lower part of the body may be paralysed temporarily by inserting Anesthetics at the space at the end of the spinal cord. It is possible to extract some cerebrospinal fluid (that forms in the brain and moisturizes the place flowing down to the spinal cord to enable the brain and the cord to absorb sudden blows) from the lumbar region, situated at the bottom of vertebral column for a pathological study as it may aid much in detection of some problems in the body. However, un-necessary extraction of anything from the body by an un-natural procedure, specially other than fluids of the body, must strictly be avoided as it has its adverse effect physically and spiritually to the individual. As a Muslim, I do not appreciate any un-natural addition to or extraction from the body (except for necessity upto necessity and that also not for a few matters such as eating from a human body even when death seems inevitable) as Islam is always taken as The Natural Path of Human Beings (in fact all the creatures for that matter) and so it does not favor such attitude. Also we Muslims do not appreciate women-folk to ask for their treatment from the male surgeons except for matters that are not gynecological or obstetrical in nature and where physical examination is totally omitted and a verbal session happens to be enough to detect the problem to provide its treatment well. We also have reservation where women treat men or female nurses tend them. There are other matters too that raise moral questions by the Islamic outlook and so as quite a few Islamic moral values are threatened by the current system of medicine and surgery even with its emphasis on consent for treatment and on patient welfare (though these good terms become useless at times as surgeons take the terms by their own personal understanding and not by the patient’s perspective in emergencies), I think that a radical change in the surgical set-up is necessary specially by the Islamic Viewpoint so as to better the situation very soon or its challenge to Islamic Morals may lead many staunch Muslims to abondon it totally in many a physical affliction accepting death of the physique for sake of purity of the spirit where they may be saved quite easily. May Allah guide understanding persons to really care about Humanity and not only talk about it.

(6) The Endocrine System is related to hormones, secretion of the human body that guide different organs to perform different tasks. These hormones are produced by different ductless glands (small organs that have no tubes to transport their hormones to the blood yet allow the blood and lymph to fill them well and as such carry their respective secretions with them ahead), located at different places in the human body. Hormones are classified as internal secretions as they are produced by glands to affect other organs (other glands included) to perform specific tasks and as such hormones are guidance system that control the body to keep the homeostasis intact. As all control of the body is located at the brain that apply by three systems of the human body (the other two besides the Endocrine System are the System of Psyche that has whole of the brain with a emphasis on the spinal cord as its master organ and the Nervous System with cerebrum as its master organ), the master organ of the Endocrine System (Pituitary Gland) is also located at the brain. Hormones, the internal secretions, are produced by pituitary gland (a cherry size gland located at the Brain, just besides midpoint of the optic nerve below the Hypothalamus), thyroid and parathyroid glands (located in the neck attached with trachea like a butterfly), thymus (located a little below thyroid and parathyroid glands and works actively at the beginning of life producing hormones that asks lymph tissues to strengthen lymphocytes that help to combat infection, yet decimates a lot in size decreasing its work as the child grows on), adrenals that are also known as suprarenals (located above kidneys as their hats one at each), pancreas (located at the abdomen besides liver, stomach, spleen and other organs that besides the production of pancreatic juice which acts on Carbohydrates, Proteins and Lipids, produces the hormone “insulin” to secure the use of sugar in the body for if insulin is absent, sugar increases highly getting totally out of proportion in the blood with other components thus leading to Diabetes), respective masters of Reproductive System (pair of testes in male and pair of ovaries in female located at the pouch outside the body and at left and right of the uterus respectively). The pituitary gland produces a number of hormones mostly to stimulate the other members of its system to produce their hormones due to need in quantity needed in the body that their hormones could satisfy well and in fact its hormones somato-tropic (the growth hormone) and ADH (the water-retaining hormone) affect all the vital body organs favourably. This automatically implies that it is always aware of needs of the body that it has to fulfil and for that it takes aid of Hypothalamus as per requirement. Its product “thyro-tropic hormone” stimulates thyroid glands as it reaches there by flow of the blood to produce its hormone “thyroxin” according to need to regulate the metabolism for production of heat in the body tissues. Thyroid Gland uses the salt “iodine” to produce this hormone so that must be provided to the body by an adequate diet as the lack of that makes the Thyroid Gland work much harder to provide necessary thyroxin to the body resulting in formation of a goiter. Parathyroids the nearby glands to thyroid gland and they are part of it, provide a hormone “Parathormone” to regulate the exchange of calcium between blood and bones and as each hormone performs one sided task asking its specific organ that is the target to which it is sent, to do something in the situation at hand (not stopping from something) thus parathormone asks the bones to increase calcium as per required in the blood. Coming to pituitary, another hormone that the master gland produces is “adrenocortico-tropic” (ACTH) on the impulse from hypothalamus that stimulates adrenal glands to produce its hormone “adrenaline” also known as epinepherine (and its other hormones named ahead) according to need to prepare the body to face occasions that ask for fight or flight attitude immediately. Adrenaline affect the sympathetic nerves at once and ask the liver to release its glycogen as sugar in the blood so that the muscles may use them as raw material for production of energy needed to face the stressful occasion at hand. As a result a dilation of the bronchioles is also produced increasing intake of the air while increase in rate of the heart-beat is also experienced. Adrenals also produce “gluco-corticoids” that stimulate amino acids to convert to sugar according to need instead of proteins to which they usually convert and they also affect the body favourably to counter the inflammatory response thus decreasing the sensation of pain and as such are also administered medically to provide relief from it. In addition, adrenals also produce “mineralo-corticoids” to regulate the electrolyte balance needed by the body and the major hormone in this group is “aldosterone”. Pituitary gland also produces “somato-tropic” hormone that helps in growth of all the organs of a person while it also produces the hormone “gonado-tropic” to affect the male and female respective reproductive organs so that these organs produce their respective hormones “testosterones” and “estrogens” to see to development of the male and female characterisics respectively. There is another hormone too that is produced by the female sex organs namely “progesterone” to assist in the development of pregnancy. It is interesting to note that Pituitary Gland in females produces hormones like “oxytocin” to stimulate the uterus to contract much to force the child out at birth and “prolactin” to stimulate the production of milk for its nourishment thus a great care for the coming of a new life is provided in the humankind. In fact allow me to present a Islamic point that I remembered here and it is that “Murder” is the second big sin while “Adultery” (fornication included) is the third big sin according to Islamic viewpoint and these both are related to departure and arrival of a new life in the world respectively so human beings are given a great respect in Islam indeed. Please note that the first big sin according to Islam, is to take anyone equal to Allah and a Muslim is one who believes that Allah is One True Source of all Power and He Only, The Only True Lord, causes people and any thing in the Universe to help or create trouble for men and any other creation. The only aim of life of all men and women is to worship Allah and there is no other aim of life for sure.

(7) The Immune System of the body works to keep the body in balance for survival and so takes care that no such thing that is adverse to this balance (homeostasis), affects the body. It may be termed as “resistance” of the body to disease that has three natural levels on which it works to keep the body safe and sound according to the danger faced. The first level is the presence of skin, natural built and fluids of the body so the bodies that are adverse to the physique do not enter, or get neutralized as soon as they enter, the body. This level includes many natural activities too that we all perform in routine including coughing, sneezing, bathing, and even visiting the wash-room as these all expel many things that are adverse to homeostasis of the body. The second level is where the adverse bodies find their way into the blood in a high number and that needs a counter force to destroy their power which is provided by different types of leukocytes (the white cells that are produced by marrow of bones in the body) while occurrence of fever is also included here as the body destroys the invading adverse bodies by exposing them to heat that destroys much of the pathogens providing us the knowledge that there is a problem inside where an outside help may be needed (due to this, we may also include pain here as it also is an informant to us for sure). The third level is where the adverse bodies do find the power to destroy second line of defense of the body to a threatening height and that is where each and every master organ with the co-operation of all other parts and circulation of the blood becomes a defensive weapon to combat the invading bodies. Here, we would study the second level of defense as the third level of defense is related to Pathology and needs a specialized dealing while the first level of defense needs no extensive comments to understand well. The second level of defense consists of function of the white cells and these cells are named Granulocytes, Monocytes and Lymphocytes, all present in the blood. The first two work mostly as Phagocytes that is the cells that eat up the adverse bodies (and that is well understood if you keep the fact in view that these both are strengthened much by function of liver in the body that is the master of Digestive System and to a lesser degree even by function of spleen in the body) while lymphocytes (all of which are strengthened much by function of spleen) work by diplomatic style (B-lymphocytes) for destruction of the entered adverse bodies, producing anti-bodies to affect them as toxins to them and if necessary, by changing to missiles (T-lymphocytes) to destroy the adverse bodies totally catching them unawares. It is interesting to note that pathogens also work in these two methods, indirectly by forming toxins to destroy the body-works and directly to invade a body part aggressively so there are two aspects to their virulence i.e. power to affect the body adversely. Although, spleen works on both types of lymphocytes to strengthen them yet those lymphocytes that mostly are in touch with thymus, are given a special preparation to fight as missiles and so they are called T-lymphocytes while all the others are named B-lymphocytes. All the four organs Liver, Spleen, Bones and Thymus have an important role to play in this system yet I would term Spleen as the master of this system as this wonderful organ that is located at the abdomen on the left side composed of lymphoid tissue in the vicinity of other vital organs, is so active in countering effects of the bodies challenging homeostasis of the body that I consider it deserves the title well. Also, spleen works as a blood bank in the physique while filtering the blood through its lymphoid tissue discarding all the torn particles saving their iron for further use in the blood flow itself. As for ratio of the white cells, Granulocytes are present above 68%, Monocytes about 6% and Lymphocytes about 26%, all working in harmony with each other. The first two are named as Phagocytes as they eat up the adverse bodies in which most probably they find some kind of natural taste. Actually all pathogens have a substance “antigen” in them that is poisonous to the body and that causes the body to take a guard against them and this is the reason the Phagocytes eat up the bodies that contain antigen. As for the function of lymphocytes, they work as B-lymphocytes and T-lymphocytes. Specific antigens are present in the pathogens that are all around us that target specific organs yet a specific antigen does stimulate the lymphoid tissue that are present in groups all over the body (and these all lymphoid tissue strengthen the lymphocytes) specially spleen that is adept in dealing with such situation, to tailor specific anti-bodies against it keeping its size and shape in view. This tailoring is performed by the resident B-lymphocytes in those tissues that get the idea of size and shape of the pathogen containing the antigen in target by information received from other B-lymphocytes as they touch the resident B-lymphocytes. In turn, the former had taken it before presenting it by their touch to the pathogen so these circulating lymphocytes act as couriers touching the target getting all information needed and then providing it to the resident B-lymphocytes that change themselves to what is named as Plasma Cells for necessary action. These antibodies are produced so well in shape and size that they fit the specific pathogens wonderfully well and cause complements (nine protein particles made by liver) to attack the pathogens forcefully destroying them with their antigen immediately. This also implies that different diseases are caused by different pathogens so when pathogens containing a specific antigen enter the body in quite a number, Spleen and other Lymphoid Tissue tailor its apparal in accordance with its size and shape thus trying their best to combat them all well as antibodies target only their specific pathogens. However, the T-lymphocytes do not trouble themselves with such procedure of cause and effect but as they find pathogens which they recognize easily as these pathogens are totally foreign to all that is usually present in the body, they attack them directly attaching their own selves to it. They release chemicals that affect the antigen in pathogens adversely and also ask for necessary assistance of phagocytes to terminate the invaders saving the body sacrificing their own-selves.

(8) The Skeleton System consists of the framework and the function of Bones and Joints. These play a very important role in defense of the body as built of the entire body is due to hold of the skeletal framework. Also, it manufactures initially both types of cells of the blood (red cells that hold oxygen and white cells that end pathogens) by the function of its marrow and it stores calcium too providing it whenever hormones inform them about its shortage in the body. Another important function of bones is to provide for voluntary actions working in co-ordination with voluntary muscles at joints that have origin and insertion in them. Bones except for joints, are enclosed with peri-osteum (its membrane that also contain osteoblasts, the bone-building cells) that plays an active part when growth or repair of a bone is needed. The Cranium that serves as a protection to head, is composed of eight distinct cranial bones while the Facial Area is composed of fourteen bones but in addition, this upper portion of the body also has three tiny bones known as ossicles in each of the middle ear plus a hyoid bone at the lower side of the skull where the tongue has its attachment. Note that whole of the body skeleton is a one unit system yet for the sake of convenience in study, we categorize the bones. The bones at the middle of the body are named thorax (the Breast Bone with Ribs) and verteberal column (the Back-Bone or Spine). The back-bone comprises of twenty-six vertebrae that are small irregularly shaped bones linked with each other in a series by strong connective tissue forming a cylinder that performs the very important task of holding and protecting the spinal cord inside (all these small bones have holes called “foramen” through which the spinal cord passes down connected to cerebrum, brainstem and cerebellum). The back-bone is so very important that the whole skeleton lies on its support and in fact, feature of the whole body depends on it. Also, its usage in common language to denote something of strength in a matter tells its distinguished status thus leading to conclude that this part of the skeleton is master of the Skeletal System. As for thorax, it consists of cage that has twelve pairs of ribs (connected with the Breast Bone that forms middle of thorax also known as sternum) and interestingly, the first seven pairs attach to sternum directly while the other three pairs after them attach indirectly to sternum by attaching to the respective rib above. The last two pairs do not attach to sternum directly or indirectly and remain without a joint at one side and so they are named floating ribs. The spaces between the ribs contain muscles, blood vessels and nerves and like all other important bony structure, it serves well as a protective shield to the heart, master of the respiratory system. The shoulder consists of the clavicle (the collar bone) and scapula (the shoulder blade) while the upper arm consists of humerus that forms a joint at the scapula above and a joint with two fore-arm bones (ulna and radius) at the elbow-joint. The wrist consists of eight small carpel bones that form base of each hand joining it to ulna and radius while five meta-carpel bones form the body of each hand. The rounded ends of meta-carpel bones may be seen as knuckles while there are fourteen phalanges (finger-bones), two for the thumb and three for each of the fingers. Bones at the lower body have a similar formation as bones of hands though here the bones are longer and stronger so as to bear all weight of the body. The strong bony ring that is formed by two hip bones at the origin of legs that complete the round at the back with a joint to sacrum, the bottom part of vertebral column, is called the pelvis. It protects the urinary bladder and the reproductive organs specially so in body of the female, where it is much broader to accommodate the uterus that holds the pregnancy. Both thigh bones named “femur” originate from pelvis with a hold at special sockets that are provided in pelvis, left and right. This bone which is also called the thigh bone, is the longest and the strongest in bones of the body making the other joint at the knee-cap. Next come “tibia” and “fibula”, two bones at each leg that have their joints at respective ankles and from here, feet are built the same way as hands yet they are less mobile and much flat to provide an easy walking.

(9) The Sensory System plays the part of a wonderful teacher that gives us the power to see, hear, smell, taste and feel so as to learn so much about ourselves and the universe around us. Its master organs are eyes, ears, nose, tongue and skin respectively. It works by the aid of Nervous System as a “sense” takes place due to interpretation of the brain provided for impulses received. A visual sense is experienced (or in other words, we view all things) when the Cerebrum interprets the impulses received from eyes and a hearing sense is experienced when the cerebrum interprets the impulses received from ears. Likewise, as impulses are received through nerves from the nose, the tongue and the skin, cerebrum interprets them all accordingly and we experience the sense of smell, taste and feeling respectively. We can say that it is the brain that sees, hears, smells, tastes and feels pleasures & pains as it is the area where the final judgment to each of these works is provided while the master organs of these works are the sources by which the information (impulses) are passed on to the brain for its final judgment. However, we must credit the five sources of these five senses as master organs in our study as the brain has its control all over the body by its nerves, hormones and pyschic-effect. Eyes work by the rays of light that pass inside them and that is why we can not see in darkness. Each eye has three layers namely sclera, choroid and retina where receptors of the visual sense are located. These receptors are divided into two parts i.e. “rods” that are the detectors of black and white colour and “cones” that are detectors of red, green and blue. As the light passes inside the eyes through cornea, the front part (and this is the only part of sclera that gives a passage inside to the light), it passes on from aqueous humour (the fluid that is behind cornea and in front of lens that helps maintain the structure of cornea) to the lens and then to the vitreous body (jelly-like fluid that helps maintain the structure of whole of the eyeball). All these parts i.e. cornea, aqueous humour, lens and the vitreous body help to bend the light a bit so that it focuses well at the retina-point at the back from where the visual impulse is passed on to the brain. Note that there are two intrinsic muscles (inside muscles) in each eye, one is iris that is two muscular extensions from left and right inside the aqueous humour having its origin at ciliary body, the other inside muscle which is a part of the choroid layer. These two muscular extensions of Iris do not join in the center and so provide a gap (pupil) by which light passes on to the lens and it also has the ability to adjust the gap through control of nerves, widening it in a dim light and shortening it in a strong one. The other muscle ciliary body has its effect on the lens adjusting it according to weak and strong light that is received inside. The visual impulse that reaches the brain has the view inverse and small in size but the brain judges the visual impulse well and provides a clear and correct view of whatever is seen by the eyes. The blinking of eyes provides lubrication to it by distribution of its fluid and tears also provide for the cleansing of eyes while eyelids protect them from dust and dirt. As for ears, they are the master organs for hearing and receiving direction of heard voices. It may be divided into three main sections namely the External, Middle and Internal ear. In the external ear, the outside upper projection is called Pinna while the inside area (opening) of about one inch is called external auditory canal. This canal has glands that produce wax like substance and if this wax dries, it may block the auditory passage so that wax must be removed for a clear hearing. At the end of this canal is the eardrum that is a membrane serving as a boundary between external and middle ears. The pressure of air is normally balanced at its both sides as the middle ear is an air space that has a passage to the pharynx and this also tells that any disease that affects the throat may affect the middle ear (and the nose too) due to its access to the place. This middle ear has ossicles that are not only helpful in guiding the auditory impulse to the path it must take towards the brain (as they amplify the sound impulse that has been forwarded by the eardrum getting it by its vibration), but also assist in the detection of direction of the heard voices. As a voice reaches the eardrum through the auditory canal, it vibrates and this vibration of sound creates waves that affect the ossicles in the middle ear that give it a safe passage towards a fluid present in the internal ear that is called “perilymph”. The internal ear consists of three bony divisions that are vestibule, cochlea and the semicircular canals and all three have perilymph. In addition, bony semicircular canals also have another membranous canals inside them while cochlea also has another bony structure that is membranous cochlea and they both contain another fluid “endolymph” in them. Perilymph conducts the advancing waves towards the endolymph through the membrane. In turn, endolymph stimulates the tiny hair-like receptors to which it is in touch that initiates the nerve impulse according to the sound heard and that is transmitted to the brain for its interpretation and judgment. The membranous cochlea have nerves for the hearing while membranous canals have nerves that are helpful in detection of the direction. This process of hearing takes fraction of a second as we all know so indeed as all works of Allah, it is another master-piece. The taste impulse initiates at the tongue at its taste-buds (taste receptors) and carried to a portion in the front part of the brain for its interpretation. There are four basic tastes and all are taken up by different parts of the tongue well. “Sweet” taste is taken up by receptors at tip of the tongue and also “Salty” taste is taken up here, “Sour” by receptors at the sides and Bitter at the back of the tongue. As for smell of things that we sense, the receptors are located at upper part of the nose in the olfactory epithelium. Due to placement of receptors so high, it is sometimes needed to detect a smell by sniffing it taking it near to nose and it is worthy of note that smell has a special effect on the taste of an edible thing as a nice odor does attract a person to edibles as we all know while a person does keep away from whatever that stinks. Fifth of the subjects here in the Ninth Sytem is Skin and it is such an important part of the body that sometimes a whole system is assigned to it that is named as “integumentary system”. Skin is the largest organ in the body and taking the idea that it initiates at the face, all five master organs of the ninth system have their presense at the face (skin of-course covering the whole body as it extends down after its initiation). It functions to keep away all pathogens from the body and thus has a very important role to play in first level of the immune system. Its another important function is to get the information regarding the environment it experiences so that all necessary steps may be taken by the brain to ensure the safety of the body keeping the homeostasis intact, in the environment it is placed in. Like Homeostasis, Adaptation is also a concept in Physiology that means that organs tend to balance themselves with the situation faced even when they are damaged a bit so that the security of the body is not threatened and it also includes the meaning that a load is transferred to some other part of the body if an organ is damaged badly and is unable to perform its task well. Of course, Adaptation itself is based on Homeostasis and there is another concept too again based on Homeostasis that must be given due consideration that all the things that go away from the body even they tend to help the body in all ways possible just like the things that are accepted inside. Thus we find bile working on fats and taking care that the eaten food does not stink to cause problems to organs in their work at abdomen while urine cleanses the passage that it takes from the body to outside. Tears are the best cleansing fluid for eyes and sweat helps to keep the body cool as much as possible and indeed, you may take many such examples as you learn so this is a wonderful set-up that Allah has established in the human body (and in fact in all the universe around us). Skin also helps to emit heat as much as necessary to the surrounding for homeostasis of the body while it also takes care that the body remains cool by forming sweat where and when necessary (if the air is dry it would take up sweat fast thus cooling the body while if it is humid, it would not take it up easy and there are other natural matters too including the weather at any given place that tends to remain inside a limit so it seems that everything in the creation cares about its Homeostasis, giving a message that if we could keep to what has been provided to us that would be the best to manage for us. In Islam we have this concept by the name of “Fitrat” that all persons have a born sense of Truth that must be recognized and appreciated in practice as that leads to height in spiritual power. In other words, it needs to keep what is given for development instead of trying to better it in any way). Skin also takes care that any sensation that is out of a normal feeling is given to the brain via nerves very fast so a swift judgment to better the situation may be achieved at once. As absorbing power of the skin is not much, ointments are mostly used to treat local problems where and when necessary and its excretion of water (and salts) is also according to necessity only in a small quantity. Observation of skin tells us much about the local problem as it adapts to the problem it faces sometimes changing color and mostly forming a scar in response to inflammation wherever and whenever necessary. We see the white cells working on the wound if the skin cuts itself by some sharp object to create a covering that stops the flow of blood out and to manage the bacteria that may find entry through this accidental opening. Skin needs an exposure to sunlight for its health while a care must be taken that it is not exposed to any adverse effects that are rendered by chemicals and toxins to it.

Now, as we have come to end of our brief account of Physiology, I would ask all my readers specially the western readers to take care that Knowledge is a great thing that has the ability to provide for betterment of human beings so we all must care about Humanity with our knowledge if we want to live as a family in the world that is becoming a global village trying to tolerate the difference of belief and practical values each of us have. If that is not done at this moment of time, we would fall away even far apart from each other than before and that would be fatal to the quest of knowledge as we can learn so much from each other. May Allah guide all understanding persons to care about safety, security and sanity of all people of the world and not just talk about it.

(all praise is for Allah)

Muhammad Saleem Dada

(completed this writing on 5th December 2004)

Dada's Writings at Weebly

My Urdu Poetry In English Letters

Suicidal Tendency in Astrology

Towards Islam Through Observation


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