Structure Of The Skin

3. Structure Of The Skin

In humans the skin is well-defined. Its membranous and cellular texture covers the whole external surface of the body. It serves to surround and hold its contents together. It continues over the lips, and up the nostrils proceeding into the innermost parts of the body.

The same membrane proceeds from the lips into the mouth and lines all of that organ’s cavities. It covers the tongue and glands and extends also to cover and line all the parts of the throat and windpipe.

It leads to and through all the innumerable sacs of the lungs, lining the airways of that organ, branching so extensively therein that it presents a surface equal to and perhaps even more vast than the whole of the external body visible to the eye.

The external skin thus gradually fades into the internal but both represent a continuum, a melding together of sudden changes both in composition and functions.

The skin proceeds down the esophagus and into the stomach and through the whole of the intestinal canal. It lines all the ducts and tubes which open into that organ for purposes of servicing and feeding. It also lines all the cavities and organs in the body in a continuous and amazingly intricate network of extremely small meshes through which countless numbers of infinitesimally small capillaries, as many as 180 per square inch, wind in and out providing channels for blood and lymph as they course through and about the body performing their many and diverse duties. The multitudinous numbers of nerve tendrils also wind their own way within and without the membranous meshes and so numerous are these filaments of nerves and vessels that it is impossible to puncture any part without ‘harming one or the other or both in the process.

All parts of this amazing network of skin cells must be both serviced and protected so that they can continue to function efficiently as defending and enclosing entities while all the while synergistically working as a single confining unit within an incorporated living system.

Through this vast network, internal man has contact with his external world. Through it and by means of its many passages must enter everything intended to become a part of it or which is intended for elimination from, the human body. It houses and contains, confines and molds, gives structure to all organs, systems and parts resident within the body, including over 70,000 miles of channels and tubes.

And, in the whole of it, there is no cleavage or break. It acts as a barrier to physical agents, chemical poisons, and other agents such as insects, molds, bacteria, and other parasites which might have a deleterious effect on the body tissues and fluids, including the blood.

It may not be vitally important for students of Natural Hygiene to be able to name all the many intricate parts of the skin but we do believe that all of us can get a better understanding of our own bodies and how we function and why it is so very important to have as corrects nutritional regimen as possible if we do become acquainted with some of the gross details of this very important organ, the human skin.

The skin, like all of Gaul, can be separated into three rather distinct, but nevertheless intimately related, parts known as membranes.

3.1 The Outer Skin

The outer skin is that part of the skin which all of us recognize as THE SKIN, the outer covering which we can readily see and touch, the part that holds everything else together and prevents this and that from wandering off and leaving us behind! It is known by various names such as the hide, the epidermis, the cuticle, and also as the scarf skin.

This outer skin develops from the ectoderm, the name given to the outermost layer of cells in the embryo. The epithelial ectoderm separates out at about the fourth week of fetal life and from that point on the epidermis or outer membrane starts to develop and, in the process, splits into several specialized compartments.

The outer membrane or epidermis (in our discussion we will use the term epidermis) varies in thickness in different parts of the body. Sometimes it is thick, hard, and even horny in texture as, for example, in the palms of the hand (especially in laborers and other person who do hard work using their hands); or on the soles of the feet. It is interesting to note that these particular areas are somewhat thickened even at birth as if anticipating their future roles.

The epidermis is several cells thick and is composed of two distinct layers. The external or horny layer is made up of dead cells which are constantly shed from its surface. This layer is known as the stratum corneum.

The stratum corneum consists of slabs of flat, platelike cells which have no nucleus and thus no viable function. This is why they are called “dead” cells. They are dry and scaly and are continuously being sloughed off and then replaced, this process taking from three to four weeks. The cells of which it is composed are pushed up from the living layer which lies just below.

As new cells are born they simply move forward to replace those sloughed off. This is why correction of the diet produces rather spectacular and rapid changes in the appearance of the skin. Clients who may have consulted with skin “specialists” for years are, more often than not, greatly relieved and gratified with their new look after only a few months of following a more appropriate diet. You should be able to explain why from the information contained in this lesson.

The cells in the lower level form a single continuous sheet of somewhat flattened cells. This layer is also known as the stratified epithelium. Nature has been most ingenious in building this part of the outer membrane. Between some of the cells there is a thin layer of intercellular mortar, a kind of “stick-um” which is secreted by the cells themselves, the secretion holding one cell to the other, just as mortar holds one brick to the next.

There are still other cells which have intertwining plasma membranes which reach out “like the tentacles of an octopus,” locking the cells together somewhat like pieces of a jigsaw puzzle. These intertwining cells represent the true barrier to the penetration of the inner sanctum by undesirable foreign matter.

The ingenious locking-together arrangement also blocks the pell-mell exodus of body wastes so that they can be sent to more appropriate and designated channels. This unique physical arrangement serves to keep the inner body intact and also prevents it from melting away during a heavy rainstorm or from going down the drain when we take a shower! It permits the skin, as part of a total nutritional program, to be bathed while, at one and the same time, the diluting force of water cannot adversely affect body fluids.

Some Hygienists have written us in recent days with respect to the dangers they believed might be inherent in polluted city tap water relative to bathing. The above arrangement should eradicate such concern although it is always important to use the cleanest water available simply because of the presence of chemicals in solution which can adversely affect the skin. But it is well to know that the water itself will be prevented from entering the system to any appreciable extent via the pores.

The epidermis is insensitive since it possesses no nerve endings. It has no blood vessels and, since the cells have no functioning capacity, they therefore require no nutriment. Thus it is that there is no provision for any kind of transportation mechanism to this surface collection of cells. It has no need for capillaries, for arterioles, so these are nonexistent.

Afferent and efferent nerve fibers end beyond this dead layer. Since they do not penetrate into it, this is why the epidermis itself is insensitive. Constantly we observe that, in the living body, where there is no need, the body does not provide! Thus it is that the body meticulously guards its resources.
The epidermis also makes up the nails and hair, about which we will hear more later.

3.2 The Second Layer

The second layer of the outer membrane is the living layer of cells. It is known as the stratum malphighii or germinativum, meaning germinating layer. It is also known as the dermal layer or dermis. We will content ourselves with the name dermis.

The human dermis is a beehive of activity. Its complexity and design are cause for wonder. Irwin I. Lubowe, M.D., in his book, New Hope For Your Skin (as reported in “The Natural Way to a Healthy Skin” by the Editors of Prevention Magazine, Rodale Press, Emmaus, Pennsylvania 18049, 1972) reports that every square inch of the human skin contains the following:

• 78 nerves
• 650 sweat glands
• 19 or 20 tiny blood vessels
• 78 sensory apparatuses for heat
• 13 sensory apparatuses for cold
• 1,300 nerve endings to record pain
• 19,500 sensory cells at the ends of the nerve fibers
• 160 to 165 pressure apparatuses for the sense of touch
• 95 to 100 sebaceous glands
• 65 hairs and muscles
• 19,500,000,000 individuals cells.

We also know that our skin covers an area of some 24 square feet and can weigh as much as six pounds.

The mucous membrane is a term applied to that portion of the outer skin which lines the internal cavities of the body. There are three general kinds of membranes:

1. The outer skin or epidermis, which we have just discussed.
2. The fibrous membranes which surround all the bones, the cartilages and tendons and which also line the spinal canal and the cavity of the skull.
3. The serous membranes which line the closed cavities, such as that found in the abdomen. This membrane also surrounds all of the various organs resident within the cavities.

The specific purpose of the fibrous and serous membranes is to cover and line all the parts they service, to help hold them in their assigned positions, to secrete a special fluid which moistens and lubricates parts as they are caused to move one upon the other by body movements and activity, and to absorb any fluid which may, by one means or another, find its way into their field of operation.

The passageways of the inner body are lined with mucous membranes. All the various tubes for ingress and egress are lined with mucous membranes and anything which enters or leaves the inner sanctum must perforce pass through and over these membranous surfaces.

This membrane furnishes the appropriate tubes and organs for conveyance, exhalation, elimination, and perhaps other necessary functions. It also furnishes appropriate mucilagenous substances (mucus) as and when required and for a multitude of necessary body processes such as digestion.

The student can readily see that the skin is a part of every nook and cranny within the living body. Except for the extreme outer layer of cells of the epidermis, it is a wondrously alive part of the whole, and actively concerned in some manner with just about every function that takes place within the body. This is why its nutritional upkeep is so very important to the maintenance of a high level of systemic health. As the body is nourished, so is the skin nourished and as the skin functions in health it contributes positively to the health of the whole.