The skin, which covers a total surface area of approximately 1.65 m2 and which weighs in total about 9.5 kg, is surely the largest and the heaviest organ of the human body; yet its miraculous functions are still a puzzle to us.
A layered structure
The human skin is composed of three layers: the epidermis (outermost layer), the dermis (vascular connective tissue below the epidermis) and the hypodermis (the deepest portion of the skin), each of which has a very complex metabolism of its own. Each of the structures of which the skin is comprised has a wide variety of functions; all of these functions must be in order if we are to maintain our good health. In particular the epidermis and the dermis each have their own distinct functions, but also share some duties, and all of these are essential for the survival of the human. The thickness of the skin varies from 8 mm on the palms and soles of the feet to nearly less than 1 mm on the eyelids. Within the epidermis are found four difÂ¬ferent types of cells that undertake different tasks; the appearance of our skin, in terms of texture, evenness of color, hydration, and overall youthfulness and constitutional health, is greatly dependent on the interaction of these cellular functions.
A single organ with several functions
It is very interesting that the majority of people are not aware of the fact that the skin is one organ.
Not only does it cover the body, our skin performs many amazing tasks such as,
-helping with water conservation,
-helping with the maintenance of body temperature,
-perception of touch
-providing a barrier to harmful germs,
-storing vitamin D,
-acting as a mechanical barrier against knocks or bumps,
-helping in the removal of the waste products of metabolism
-providing protection against environmental influences, such as cold or high temperatures, and destructive ultraviolet rays, as well.
It is common knowledge that the major task of our skin is to protect the human body from harmful environmental factors. It is, indisputable that the fundamental purpose of the skin is to provide a flexible, protective shield between us and the outside world. This is made possible by the layers of flattened epithelial cells which hinder micro-organisms and chemicals from entering the body.
The benefits we have mentioned would not last long, however, if skin cells were not renewed. This amazing regeneration process happens through a replacement operation that is dependent on a continuous cell division in the basal layer. As the cells move towards the outer surface they lose their softness. Consequently, they gradually die off and stiffen. Dead cells are constantly sloughed off from the upper surface of the epidermis and are continuously shed; they are replaced by new cells that are generated in the deeper layers. This process is often referred to as “cellular renewal.” As cells progress through the various stages, they finally stiffen and die or keratinize. This dead cell layer, or keratinocytes, makes up the outermost layer of the epidermis, the stratum corneum. These hardened and cornified cells are designed by our Creator to act as a protective barrier; otherwise, living cells would not be able to provide the protective qualities necessary to isolate the living tissue from exposure to possible detrimental substances and organisms. The living epidermal cells die by an extremely sophisticated process, displaying a voluntary self-sacrifice that enables humans survive, an evident blessing from our Most Gracious Lord.
Regulation of body temperature
The regulation of temperature is considered to be one of the major duties given to the skin. We naturally lose water through constant evaporation throughout our lives. It is of utmost importance that the loss of too much body fluid is prevented. By narrowing or widening the capillary blood vessels and also by means of numerous sweat glands, evaporation on the surface enables our skin to become cooler or warmer, in a strictly limited range of temperatures. The fat cells of the skin prevent losing too much heat, and when the body overheats, the skin’s extensive small blood vessels carry warm blood to the surface where it is cooled. So, as we can deduce from this, the main task of the skin is to prevent the loss of body fluids through evaporation.
Another task of the skin is the storing of fat and the production of vitamin D [25-dihydroxycholecalciferol]. Vitamin D is a fat-soluble vitamin that is found in food and can also be processed in our body after exposure to ultraviolet (UV) rays from the sun. Sunshine is a significant source of vitamin D because the UV rays from the sun stimulate the synthesis of vitamin D in the skin. This fundamental feature of our skin is, clearly, indispensable to our skeletal development.
The human skin has also a function in sense communication with the environment. It gathers sensory information from the environment; this is performed by means of a great number of receptors (for example, those for warmth and cold) and intraepithelial nerve endings. Nerve cells in the skin form the body’s first contact with the outer world. At the moment of birth, an infant’s first experiences of the physical world are perceived through the sense of touch. Nerve cells allow the skin to receive and transmit signals from touch, pain, tickling, etc. As the skin is the boundary between a living creature and the world around it, it is also the physical interface between the creature and other creatures and the world. Hence it is the location of all contact, good or bad in kind. The Qur’an declares that the skin will also testify when we are called to account on the Day of Judgment:
Until when they reach it, their ears, and their eyes, and their skins will bear witness against them as to all that they did habitually. They will ask their skins, “Why have you borne witness against us?” They will answer: “God Who makes everything speak has made us speak.” It is He Who has created you in the first instance, and to Him you are being brought back. You did not seek to veil yourselves (when sinning) without ever considering that your ears or your eyes or your skins would one day bear witness against you. (Fussilat 41:21-22)
As pointed out in the verse …the abode of the Hereafter is truly alive (29:64), everything in the Abode of Hereafter will be alive. So, like every part of a human being, the skin will bear witness for or against them. The verse implies that it is the medium where all our contact is recorded and it will be an ideal witness.
Wounds and healing
Another astounding mission of our skin is its role in healing wounds. The human skin has remarkable selfhealing properties, which obviously point to an intelligent design. A skin wound heals from the bottom up and from the edges inward. In the first stages of healing, the basic connective tissue of the skin moves into the injured area. The depth of the wound determines how well it will heal; the regeneration process begins immediately, but we still do not know what the trigger is. As a wound heals, the edges are drawn together by a process called contracture. The most amazing part of this phenomenon are the later stages of healing. It is as if all the cells are fully aware when and where to end the repair. Nobody knows why they abruptly stop working and how they finalize restoration.
A shield against germs
Our skin also serves us by organizing and activating the immune system. Some specific cells, which form a network in the epidermis or in the outer layer of skin, play an important part in this activity, by regulating the immune response to germs. As a major contributor to the body’s immune system, constituting the first line of de fense in keeping out bacteria, viruses, and other organisms that invade the body, the skin is home to enormous quantities of T-lymphocytes, or T-cells. Those domestic defense soldiers attack and destroy bacteria, fungi, viruses, parasites, toxins, and cancerous cells that can cause disease. Thus, the skin is both a watertight barrier surrounding and protecting our body from a number of external assaults, never letting the undesired pathogenic germs penetrate.
Our Almighty and Everlasting Creator has granted us this gift of skin. He knows what those who are in need are in need of, and it is obvious that He is aware of the need of our cells, our organs, and our living metabolism, thus He has given the most favorable structural design to the human body. Just before we pray to Him, we should remember that the more consistent our demands, the more bountiful He will ordain. Frankly, there seems to be no way to explain the miracle of skin other than attributing it to the All- Beneficent God.
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