Originally Posted by reverett123

It is no secret that I am working on a wiki and, in the course of that, am trying to understand some things. An offshoot of that process is trying to put some things into words that we don't really have words for. I find myself in awe at times.I am going to post a draft that I just finished just to share. I know it has flaws, but I enjoyed it. Perhaps you will too-

How does one convey the awesome beauty and incredible complexity of the informational flow that forms the center of a living thing, particularly one as amazing as a human being? Viewing a living system as the movement of information is anything but fanciful. It is the reality. At any given instant, billions of tiny messengers scurry about our systems carrying instructions from one part to another. Not just in our brains, but in every tissue are found recipients awaiting those messengers. The information they convey ranges from “take a rest” to “commit suicide” to “send help.”

Analogy is a useful tool if one keeps its limitations in mind. The portrayal of these messengers as keys that bump up against locks that open if the key is a proper fit is a good example of both analogy and its limitations. It provides a glimmer of understanding, but only a glimmer, as it sacrifices complex beauty in hopes of conveying understanding.

“Beauty” is a term that is not chosen lightly. Science takes a perverse pride in avoiding such words, but there are times when no others will do. We only have vocabulary for that which we have experienced. When we confront something far beyond that experience, our recourse is to compare it to the familiar by analogy. By using multiple such tools we can approximate the reality. With these limitations in mind, let us engage in a mental exercise and explore the hidden beauty within us.

Imagine you are floating far above a fantastic landscape of what seem to be diamonds the size of a fist. Hundreds of thousands in a wide range of colors lie below you. They seem to float upon a sea and are in motion as currents move them along. This dynamic and ever-changing surface below you is a single cell and the diamonds which float upon its surface are receptors, ports that receive information from the other cells in the body. Each receptor is “primed” to react when it encounters a particular molecule in its environment. These molecules, called ligands, come in many colors themselves and both ligand and receptor must match in hue.

The receptors add further richness to the scene by not only moving about the cell surface in their hundreds of thousands, but by also themselves shifting rapidly between configurations or shapes so that they, in effect, twinkle in the night. Their colorful twinkling in some unknown and marvelous manner attracts ligands of a similar color and pulse – but only if they are present in the surrounding environment. If an appropriate ligand is, indeed, within range, it moves into position and gently bumps the receptor. Sometimes only once and it firmly locks into place in a “high affinity” relationship. Other times it bumps the receptor and backs away momentarily, then repeats the action.

Each time the ligand activates the receptor, a message is passed through the cell membrane and a cascade of actions begins within the cell. What specific actions take place are dependent upon the “colors” or types of the pair.

Cells not only “listen” via their army of receptors, they “speak” by producing ligands themselves. If a macrophage encounters an invader, it sounds a warning by releasing a cloud of message bearing ligands which move rapidly through the bloodstream like tiny Paul Reveres. As these messengers wash past other components of the body and are drawn in by their receptors, they trigger defensive reactions such as the production of antibodies. Other macrophages follow the “smell” back upstream to assist. Still other cells respond in other ways and release their own messages.

This admittedly simplistic treatment of a truly wondrous interaction is but one of thousands occurring by the billions within ourselves every second. Ligands such as cytokines, hormones, and neurotransmitters are the way the body communicates with its various parts. Their division into groups relegated to the immune, endocrine, and nervous systems is an artificial one. Receptors are not necessarily limited to one specific ligand nor are ligands limited to one specific receptor. Our cells are in constant communication with one another as surely as the guests at a social function. How well that communication takes place determines our health and even our lives.

Once more, let us return to our position floating in the darkness high above the twinkling jewels of the single cell below us. Now that we know to look for them, we can see that we are floating in a cloud of dimly colored ligands like fireflies, each drawn to its individual destination below. Far away through this cloud we become aware of distant bejeweled planets and know that we are looking at other, nearby cells. Everywhere we look, information is being passed and the heavens glow with the force of life.