In our bodies, there is a lifesaving gate: the epiglottis which is situated at the top of the windpipe. This flap covers the opening to the air passages when swallowing, preventing food or liquids from entering the windpipe.
The Journey That The Food We Eat
You were approximately 2-3 kilograms (4,5-6,5 pounds) when you were born. Your weight will increase to 30-35 (65-75) when you are 10, to 40-50 kilograms (90-110 pounds) when 15 and 50-60 kilograms (110-130 pounds) when 20-25 years old.
The reason for this huge difference is the fact that the substances in the foods you consume are added to your body in time. Some of these foods provide the energy you require to ride your bicycle, to run and to play, whereas some are added to your body and constitute your flesh and bones. Waste matter is discharged from the body. All these processes are performed in your digestive system. Organs and glands including your stomach, intestines and pancreas have roles in digestion.
THE TOTAL LENGTH OF THE DIGESTIVE TRACT, STARTING FROM THE MOUTH TO THE INTESTINES, IS 10 METERS (30 FEET).
1- Salivary glands secrete saliva, which starts the breakdown of starches.
2- Food begins as complex carbohydrates
3- Carbohydrates are broken down into simple sugars.
4- Glucose goes to the liver.
5- Insulin tells the liver to store glucose as glycogen.
6- The liver stores some glucose as glycogen.
7- Glucagon tells the liver to change glycogen into glucose.
8- When blood sugar is low, the pancreas sends the hormone glucagon to the liver.
9- When blood sugar is high, the pancreas sends the hormone insulin to the liver.
10- Some type of enzyme is secreted by the pancreas into the beginning portion of the small intestine.
11- In the beginning part of the small intestine, this enzyme cuts down carbohydrates into simple sugars.
12- Glucose is absorbed into the bloodstream.
The functioning of the digestive system is similar to the working of a petroleum refinery. Crude oil arriving at the refinery as raw material is processed by machines and refined so as to be usable. The foods that we eat are raw materials in the first stage and are then processed in the stomach so as to be used by the body. Having been broken down in the stomach and the intestines, foods become ready to be used as the nourishment of the cells and are conveyed to relevant regions of the body via blood vessels.
A single parent substance is processed in a petroleum refinery and a variety of products, for example gasoline, which is a fuel for automobiles, or the rubber used as the sole of your shoes, are derived from it. Likewise, the nutriments in the foods are broken into fats, sugars and carbohydrates in the stomach. But remember that what happens in your stomach after you eat a delicious sandwich is even more complex than what happens in a refinery. Moreover, this series of actions which we will soon discuss does not take place in a gigantic factory, but in a very small region in your own body.
The total length of the passage through which food is digested is 10 meters (30 feet). This is 6-7 times the average human height and it is marvellous how such a length is fitted into our bodies. How is it that such a long canal has been placed in a human body? The answer to this question reveals once again that there is a special design in the creation of our bodies.
Since the digestive tract, as you can see in the picture on the left page, is coiled up, it is fitted into a very small area, despite its length. This special shape is the perfect design of our Lord, Who created everything. This feature of the digestive system is only one of the wonders that Allah created in our bodies.
Do you know why your teeth have different shapes?
The reason why they have different shapes is that each has different tasks. For example your front teeth are sharp, so you can bite an apple easily. What if the molar teeth were in the front? Yes, you are right. You would not be able to bite a piece off the apple with your molars. Likewise, if your front incisors were at the back, you would not be able to grind the food you eat.
As in every single part of your body, the teeth in your mouth are also arranged by Allah in the most convenient and advantageous order for you.
Beneficial bacteria live at the back of your tongue
Bacteria are generally known to produce diseases and, to be protected from their harmful effects, people should be careful about the cleanness of both their bodies and the environments they live in. However, not long ago scientists discovered the presence of some beneficial bacteria in the human body, particularly at the back of the tongue. Yes, you've read it correctly; there are beneficial bacteria in your body. The duty of the bacteria behind your tongue is to kill the harmful microbes in your stomach. But surely this is not an easy task and it demands a series of actions. First of all, bacteria convert the nitrate found in green-leafed vegetables like lettuce into nitrite. However, the process is not over yet. Nitrite, in combination with the saliva secreted in the mouth, has an antimicrobial effect. In other words, the bacteria behind your tongue help in the production of a microbe-killing substance. As you know, microbes cause various diseases. Thanks to the beneficial bacteria that produce a microbe-killing substance, you are protected against many diseases. These beneficial bacteria are one of the manifestations of the compassion of our Lord, Who created our bodies in the most perfect way. Allah has given us many beauties and gifts. That these gifts are innumerable is related in a Qur'anic verse as follows:
If you tried to number Allah’s blessings, you could never count them. Allah is Ever-Forgiving and Most Merciful. (Surat an-Nahl: 18)
Now let's make a more detailed examination of the process of digestion. Consider breathing, swimming, riding a bicycle, eating… These are parts of our everyday lives, yet most of the time we do not even think how they occur. Our bodies need energy. We have already explained that we obtain this energy from the food we eat. But the nutriments required by the body should be simple and in particles small enough to pass through the blood vessels. Otherwise they cannot permeate the cells. However, the foods we consume are in large pieces. Therefore, we need a machine to enable the body to use the food we eat. In fact, we may briefly call this a grinder, which basically reduces the food we eat to smaller particles. This grinding machine in your body is called the "digestive system".
This system, like all machine systems, is composed of various components and thanks to the perfect functioning of each of these components, we can digest food. It is vital that components of the digestive system be harmonious and complete because the whole system fails unless they are so.
Now let us give an example to illustrate why all the components of a system should be complete for the proper functioning of the system:
A remote-controlled car is composed of parts such as wheels, a controlling device, motor, batteries, gear, coil, antenna, etc. Likewise, the digestive system is composed of various components. These include the teeth, tongue, oesophagus, stomach, and intestines.
Now think. Would a remote controlled car operate if it did not have antenna or wheels? Of course not. The car can run only if all of its parts are present. The same applies to the digestive system. The presence of the stomach would be meaningless unless there were also an oesophagus, since what carries food to the stomach is the oesophagus. In like manner, intestines cannot possibly be of any use unless there is a stomach, because the foods digested in the stomach are passed into the intestines, where they are given the proper form to be conveyed to body cells.
This clearly shows us that our Lord, the Creator of everything, created for us a system that is perfect in every way. This reveals once again that there is no other god than our Lord:
Your god is Allah alone, there is no god but Him. He encompasses all things in His knowledge.(Surah Ta Ha: 98)
Digestion starts in the mouth. Carbohydrates in the foods you eat are first broken down into smaller particles by the saliva in your mouth. For instance, the bread you ate at breakfast started to be broken down initially in your mouth. But it will take longer for the cheese you ate along with that bread to be broken down.
That is Allah, your Lord. There is no god but Him, the Creator of everything. So worship Him. He is responsible for everything. Eyesight cannot perceive Him but He perceives eyesight. He is the All-Penetrating, the All-Aware.
(Surat al-An'am: 102-103)
Nutriments broken down in the mouth pass through the oesophagus and reach the stomach. In the stomach is another marvellous state of equilibrium. Digestion of foods in the stomach is performed by a very strong fluid. This fluid is hydrochloric acid. As you know, acids are corrosive materials. They are capable of dissolving what they are in contact with. For instance, what your mother uses to clear an obstructed plug hole contains acid. Breaking down dirt and waste matters that blocked the pipe, these acids rid it of obstructions. It is thanks to the strong acid found in the stomach that the foods, which are in large pieces when they first arrive the stomach, are broken down into smaller particles that can be used by the body. Yet there is one more point that needs to be noted.
Different types of stomach cells secrete different secretions to digest the foodstuffs we eat.
I. Stomach, II. mucous surface cells, III.Gastric Pit,
IV.mucous surface cell (secretes mucus)
V. mucous neck cell (secretes mucus)
VI. parietal cell (secretes hydrochloric acid and intrinsic factor)
VII. chief cell (secretes pepsinogen)
VIII. hormone-producing G cell (secretes gastrin)
We have mentioned that the food eaten is broken down into pieces by the stomach or gastric acid. So how is it that this acid does not destroy the stomach itself, which is also made of flesh? Now, think about it. The gastric acid digests the meat, for instance, you eat at dinner, yet ignores the stomach, which is in the same way a piece of meat. Why is this so? At this point, the excellence in the creation of our Lord is revealed once again. Allah, Who created everything perfectly, designed a protection so that the stomach itself is not digested.
This protection may be summarised as follows; another fluid, namely "mucous", is secreted during digestion to prevent the hydrochloric acid from breaking down the stomach. A special mucous layer covers the inner lining of the stomach and protects the stomach from damage by this powerful acid. So the stomach does not digest itself.
The next place on the digestive route is the intestines. Nutriments are broken down into even smaller particles and are made usable by the body as they pass through the two intestines, the large and the small. What is useful in these nutriments is introduced into the bloodstream and the unnecessary residue is discharged from the body by the excretion system. The phases that the food eaten passes through in the intestines are also very important. Digestion continues in the intestines as in the stomach. Nutriments are broken into even smaller particles. They are now so small that they are absorbed by the blood vessels around the intestines and are involved in the bloodstream to be carried to every part of the body.
Children, you must have realised that the digestive system is planned completely and perfectly. During this journey, which starts at the mouth, proceeds along the oesophagus, the stomach and the intestines, the food eaten passes through several phases. And finally the nutriments that our body cells require are obtained. These are absorbed in the intestines and delivered to the body via the bloodstream. Digestion of food would be very hard if this mechanism did not work so perfectly.
One function of the stomach other than digestion is storage: Foods that reach the stomach are kept here for a period. Then they are little by little passed to the small intestine for further breakdown. If the foods you ate were not stored in your stomach, you would have to eat every 20 minutes because your stomach would always be empty and you would feel hungry all the time.
Right picture: Stomach
First of all, if we lacked teeth, we would not be able chew our food sufficiently and it would not go down the throat. Even if it did, it would seriously injure the oesophagus. If our stomach were not able to digest the food, everything we ate would remain as a large mass in the stomach, which would be quite disturbing. Besides, as a result of not being able to digest foods, our bodies would not be provided with the nourishment they require. An unnourished body loses its strength after a while and body cells start to die. But we do not experience such things, because our Lord created every single part of our bodies perfectly. This excellent system runs flawlessly, and we are quite unaware of it. This excellence in creation is related in the following verse:
He is Allah – the Creator, the Maker, the Giver of Form. To Him belong the Most Beautiful Names. Everything in the heavens and earth glorifies Him. He is the Almighty, the All-Wise.(Surat al-Hashr: 24)