Besieged Castle: The Human Body
It is a fact that
even though we try to live in clean environments, we share these
places with many micro-organisms. If you had the chance to view
the room you are currently sitting in with a microscope, you would
immediately see the millions of organisms you live with.
In this situation, the individual resembles a "besieged
castle". Needless to say, such a castle, which is surrounded by
countless enemies, must be protected in a very complete and organized
manner. Human beings are created along with this perfect protection
they need, and are not, therefore, entirely defenceless against
these enemies. The "micro" guards in our bodies never leave us alone
and fight for us on many fronts.
The invader cells that want to take control of
the body first have to fight their way through the front line of
the body. Even though these fronts have their weaknesses at times,
the enemy is hardly ever allowed to pass through them. The first
front the enemy must penetrate is our skin.
The Protective Armour of Our Body: The Skin
The skin, which covers the entire body of a human
being just like a sheath, is full of amazing features. Its ability
to repair and renew itself, its non-permeability by water, despite
the existence of tiny pores on its surface as opposed to its function
of discharging water through perspiration, its extremely flexible
structure, allowing free movement, as opposed to its being thick
enough to avoid easy rupture, its ability to protect the body from
the heat, the cold, and harmful sunrays are only a few of the features
of the skin that have been specially created for human beings. Here,
we will deal with a particular feature of this extraordinary wrapping
paper: its ability to protect the body from disease-causing micro-organisms.
If the body is considered a castle besieged by enemies, we can safely
refer to the skin as the strong walls of this castle.
The main protective function of the skin is realized
via the dead cell layers constituting the outer section of the skin.
Each new cell produced by cell division moves from the inner section
of the skin towards the surface. While doing this, the liquid element
(cytoplasm) of the cell interior transforms into a resistant protein
known as keratin. During the process, the cell dies. The newly formed
keratin substance has a very hard structure and is not therefore
subject to decomposition by digestive enzymes, which is a sign of
its resistance. Thus, invaders such as bacteria and fungi will be
unable to find anything to rip off from the outer layer of the skin.
Moreover, dead outer cells containing keratin are
constantly shed from the skin surface. The new cells that come from
beneath to replace the discarded ones form an impenetrable barrier
in that area.
The organisms on the skin fulfill another protective
function of the skin. A group of harmless microbes live on the skin,
which have adapted to its acidic medium. Feeding on the leftovers
stuck on the keratin of the skin, these microbes attack all kinds
of foreign bodies to protect their feeding site. The skin, as the
host of these microbes, is like a supplementary force that provides
external support to the army within the human body.
first defense response of the organism against its dangerous
invaders is the rapid self-repairing of the skin tissue following
the infliction of a wound. When such a wound ruptures the
skin, defence cells immediately travel to the injured area
to fight with the foreign cell and to remove the debris of
the affected tissue. Later, some other defence cells enhance
the production of fibrin, which is a protein that rapidly
re-covers the wound with a fibrous network. This picture is
of a fibrin that has spread over some red blood cells.
AN IN-DEPTH VIEW OF THE SKIN
Above is a cross-section of the skin.
The sweat droplets secreted from the skin play a variety of
roles in the body. In addition bringing down the body temperature,
they provide nutrition for certain bacteria and fungi living
on the surface of the skin, and produce acidic waste materials
such as lactic acid which helps decrease the PH level of theskin.
This acidic medium on the skin surface creates a hostile environment
for any harmful bacteria that are looking for a place to live.
|This is a close-up of
the sweat gland entrance. Here, too, you will find bacteria
just like everywhere else on the skin.
||This picture, which is
magnified 5900 times, shows the cells in the trachea (blue).
They use their glands (yellow) to secrete a substance
that traps the particles in the air.
Protection in Respiration
One of the courses our enemies take to enter our
body is the respiratory tract. Hundreds of varied microbes, which
are present in the air we inhale, try to gain entry to the body
through these passages. However, they are unaware of the barrier
set up against them in the nose.
special secretion in the nasal mucous retains and sweeps out about
80-90% of the micro-organisms that gain entry to the respiratory
system directly or through dust particles or other substances.
In addition, the tiny hairlike structures (cilia)
on the surface of the cells of the respiratory tract beat upward,
causing a current that carries foreign particles to the throat where
they are swallowed and disposed of by acid in the stomach. The coughing
reflex and sneezing facilitate this function.
The microbes that are able to surmount these barriers
and reach the alveoli (lung, bronchus and gingiva) will be ingested
by phagocytes. After this phase, phagocytes become mobile and drift
upwards with the microbes they have ingested to be finally discharged
from the body in different ways.
Each time you breathe, as you are doing now, a
war is fought at the border gates of your body of which you are
completely unaware. The guards at these border gates fight with
the enemy to the death to protect your health.
Protection in the Digestive System
Another vehicle by which microbes gain entry to our
body is our food. However, the guards of our body, which are aware
of this method used by the microbes, await them in the region where
the food finally ends up, which is the stomach. They also have a surprise
for the arriving microbes, which is the gastric acid. This acid is
quite an unpleasant surprise for the microbes which have overcome
all obstacles and reached the stomach. The majority, if not all, of
the microbes are defeated by this acid.
Some microbes may overcome this obstacle because
they have not made enough contact with the gastric acid, or they
have showed resistance. However, these microbes are again subjected
to further conflicts with other guards situated on their way. Now,
another surprise is at hand for them: the digestive enzymes produced
in the small intestine. This time, they cannot get away as easily.
As we have seen, the human body has specially created
guards, which protect the human body in every phase of the microbes'
There are now some important questions raised by
Who established that microbes living outside would
try to penetrate our body through foods, which route the food would
follow, how microbes would be destroyed in their final destination,
where they would go if they overcame this obstacle, and how in that
case they should be exposed to stronger measures? Is it the body
cells, which have never been out of the body, and therefore, have
no chance of examining the chemical make-up of the microbes outside,
and which, moreover, have not received any training in chemistry?
Definitely not. Only Allah, Who created both the
external world, and the food in this world, and the body that needs
these foods, and the system to digest these foods, is able to create
such a defence system.
Another Method: Destroying the Enemy by
There are many other micro-organisms that live within
the human body which cause us no harm. What are these organisms that
continue with their own life without doing us any harm, and what is
their purpose in living within our body?
These groups of micro-organisms, which are gathered
in certain parts of the body, are called the normal microbial flora
of the body. They do no damage and even have some benefits for the
These micro-organisms provide external support
for the defence army against microbes. They benefit the body by
preventing foreign microbes from settling in it, because the entry
of any microbe into the body is a threat to their own housing site.
Since they do not want to be displaced by the invaders, they fight
a fierce battle against them. We can think of these micro-organisms
as "professional soldiers" fighting for the body. They try to protect
the site they live in for their own benefit. In so doing, they complement
the fully equipped army in our body.
How do these "professional soldiers" settle in
The human embryo has met no enemy during the gestation
period in the mother's womb. Following the birth of the child, it
makes contact with the environment, and numerous microbes are introduced
to the child through the intake of food and by way of the respiratory
tract. Some of these microbes die right away, while others are discharged
before having the chance to settle down in the body. Some, however,
settle in various parts of the body such as the skin, skin ridges,
mouth, nose, eyes, upper respiratory tract, digestive tract, and
genital organs. These microbes form permanent colonies at these
locations and constitute the microbial flora of the human body.
Who are Our Micro Enemies?
Our micro enemies, on the other hand, are micro-organisms,
which are not a part of our bodies, yet which have somehow penetrated
our bodies, eventually stimulating the defence army therein.
foreign cell that enters the body is not, however treated as an enemy.
Foreign matter constantly enters our bodies as we eat, drink water,
or take medicine. Yet our body does not initiate a war with it. In
order for the defence cells to perceive a foreign substance as an
enemy, certain conditions are taken into consideration such as the
size of the molecule, its rate of elimination from the body, and its
way of entering the body.
Among our innumerable micro enemies, bacteria have
an established reputation.
Bacteria, which enter the human body in multiple
ways, instigate a fierce war in the body. Sometimes ending up with
quite serious illnesses, these wars explicitly reveal the power
and ability hidden in an organism the size of a few microns (a micron
is one thousandth of a millimeter). Recent research has shown that
bacteria have an extraordinary resistance even to the most severe
and harsh conditions. Particularly, the bacteria known as spores
are resistant to extremely high temperatures and drought for extended
periods. This is why it is difficult to destroy certain microbes.
human body resembles a very valuable diamond stored in a safe, receiving
the most intensive care and protection. Some of the organisms that
try to invade the body act like experienced thieves. One of the best
known and most important of these thieves is the virus.
This organism, whose existence
we became aware of with the invention of the electron microscope,
is too simple-structured and small to be considered even as a cell.
Viruses, which vary in sizes ranging from 0.1 to 0.280 microns,
are excluded from the world of living things for this reason.2
Although categorized as being apart from the world
of living beings, viruses indisputably possess at least as exceptional
abilities as all other living beings do. A closer examination of
the lives of viruses will make this fact more apparent. Viruses
are the compulsory parasites of living beings. This means, they
cannot survive if they do not settle into a plant, animal, or human
cell, and consume its food and energy. Viruses do not have a system
that would enable them to survive on their own. As if they are aware
of this, they deftly slip into a cell, and after invading the cell,
with the same deftness turn the cell into a "virus production factory"
that produces its own copies.
This plan developed by the virus to invade the
cell is extremely sophisticated and intelligent. In the first place,
the virus must determine whether the cell is appropriate for itself
or not. It has to be very careful and meticulous in this decision,
for the smallest mistake may cause its death. To avoid such an end,
it uses its special receptors to check whether the cell is appropriate
for it or not. The next important thing it does is to carefully
locate itself within the cell.
The virus confuses the cell with the tactics it employs and avoids
is how the events develop: the cell transports the new DNA of the
virus into its nucleus. Thinking that it produces protein, the cell
starts to replicate this new DNA. The DNA of the virus hides itself
so furtively that the cell involuntarily becomes the production
factory of its own enemy and produces the very viruses that will
eventually destroy it. It is indeed very difficult for the cell
to identify the hereditary make-up of the virus as that of an invader.
The virus locates itself within the cell so well
that it almost becomes a part of it. After the multiplication process
is over, the virus and other new viruses depart from the cell to
repeat the same process in other cells. During the process, depending
on the type of the virus and the cell, the virus can kill the host
cell, cause harm to it, modify it, or simply do nothing.
The question of how the cell, which operates under
a very strictly monitored control mechanism, can be deceived into
becoming a virus factory is still unanswered. It is quite intriguing
that viruses, which have a highly specialized structure, but which
are not even classified as living beings, could act so intelligently,
think up, and plan such effective strategies. The secret of this
phenomenon lies in the existence of a Creator, Who created these
organisms with the abilities they possess.
The features of the virus are perfectly designed
to enable it to make use of the system operating in the cell. It
is obvious that the power that created the virus is also well informed
about the extremely complex working principles of the cell. This
power belongs to Allah, Who created the virus and the cell into
which it will settle, as He created the entire universe.
The virus, which, with its miniscule structure,
can inflict and sometimes even cause the death of the human body,
which is millions of times bigger than itself in size, is a being
specially created by Allah to remind people of their weaknesses.
2- George Gamow, One Two Three...
Infinity, Bantam Books, 1971, p. 245