Saturday, August 6, 2011

Why?

It was sudden, abrupt and without preamble. It shut my thoughts down. These moments are rare and quite confounding to your inner equilibrium. The feeling is strange; time comes to a standstill, all else fades away except for what is. The sensation of a newborn’s tiny hands clasping the little finger of an adult, or seeing a stilled-lake-water reflecting the autumn tinged tops of the birch trees or the rising terrain glazed over with yellow and white wild flowers. These are moments of great magnitude when a question or statement or a visual arrests all mental cognitive domains of your brain.

Well that happened to me on this one innocent tweet. Yes, I said tweet. It read, “…If only I knew the questions to answers.”

Now what do you say to that? My reflexive nerve took over and I simply said, “gain more knowledge to ask the questions.” To a minor fractured fault that statement might be construed as correct but then there is a huge gash of credibility between what reality is and what the perceived goal of a quick answer would be. So I set out to somehow answer that wonderful, innocent and totally non-referential statement. 

How do you ask the questions to answers that you know not of?  I think therefore, what I am about to say is my considered opinion. Why, in that tedious and irritating curious word, whose scent lingers after it is uttered, has such a boatload of undercurrents?


So let us start with a simple and well-informed question of why is the sky blue? Simple enough. The question is out there, blue from morning all the way till the evening. Blue for each of our eternities. It is blue. But the question is why? Ah there is meat in that one word, why!


It is physics after all that governs the color of the sky. The visual field is governed by a small spectrum of wavelengths. 

The blue light spectrum has a short wavelength while the red one is on the opposite side of the spectrum with a long wavelength. 

The shorter wavelength bounces of the suspended particulate matter (Martian Dust or Tinker Bell’s fairy dust if you prefer) and gets scattered thus coloring the sky blue. As the sun declines towards the horizon the red-color wavelength rides through but the angle of inclination of the blue wavelength cannot reach the eye due to its short wavelength, the red one does, hence those gorgeous red sunsets.

 The eye too, has  it’s own sets of rules based on the anatomy. The eye has cone-photoreceptors that are stimulated by the various wavelengths. Three main types of cone photoreceptors exist: The S (short, Wavelength= 400-500nm), M (Medium, Wavelength=530-600nm) and the L (Long, Wavelength=600-700nm). Previously they were termed as RGB for Red, Green and Blue, which is disputed currently. The stimulation of multiple cone-photoreceptors leads to a blending of the three main colors giving the person a wide spectrum of the rainbow. And there is of course one more major component to contend with and that is the brain. 


The Visual spectrum is received in the occipital lobe of the brain and then the electrical stimuli spread to the dorsum and the ventral aspects of the brain collating color information for interpretation. 

Just as different cone-photoreceptors need to be stimulated by the photons striking them, so must the right brain cells be stimulated electrically to display the perception. There are specific brain cells that are stimulated only by the respective color wavelength photon induced urgings from the retinal cells in the eye. So there you have it. That is why the sky is blue in the daytime and reddened in the evening.
sunset
But you might ask, why then given this “blueness” of the sky, is the space black? After all the sky is the space and yet images from the space-shuttle and the Martian Rover seem to suggest a black void. 

That answer is simple if you follow the logic that there are no suspended, condensed particulate matter  (condensed as in: over the surface of the earth by the atmospheric pressures) in space. Hence the light does not scatter.
space black void


Other theories suggest that the stars that are receding in an ever-expanding universe have a “Red-Shift” (moving away) from the observer so as not to register a stimulation of the cone-photoreceptor due to the distances( The distance in light-years is so removed that it does not allow for the action-potential to be initiated). And of course a third theory is since 97% of the  space is composed of “dark-matter” that this absorbs the visual spectra. All of these in isolation or combination is possible, but all remain  theoretical and thus all are valid for your interpretation. So go ahead find the proof!



Speaking of perception. What a wonderful set of orbs the eyes are, a set of gateways that another can look deep inside one’s soul.  The beautifully colored irises that make for blue, green, hazel and brown eyes give beauty to the beholder. So why are the eyes colored differently in different people?  (Asking the question again with a WHY)

The simplest answer is the genes made them that way (This is true unlike “my genes made me do it”).  However there are three known main genes that color the iris (EYCL1-2-3). What is now been determined that any set of parents with any given colored eyes can induce a magical different color in their offspring outside the ream of the Mendelian Constraint (Gregory Mendel). By that I mean, if both father and mother have brown eyes a blue eyed child might emerge. (The product of a milk-man , you say) Not necessarily. There are miRNA (Microinterfering RNA) that “interfere” with the genetic signals that are transduced to create the specific protein, which endows the specific color. These pesky miRNA are found everywhere in the genetic jungle. Additionally there are the Barbara McClintok’s famous “Jumping Genes” also known as Transposons that can through series of jumps within the chromosomal belt, land on a specific gene and modify its behavior or “expression.” The colors come at a price though. The hazel, blue and light green colored irises have a higher tendency to “Age-Related-Macular-Degeneration” and loss of vision along with a risk of choroidal melanomas while the “Brownies,” have a tendency towards cataract formation. Nature balances the rewards and punishment equally sometime. What the mind sees, sometime the eye cannot.  (http://jedismedicine.blogspot.com/2011/02/human-diversity-in-genes.html)

Speaking about mind. Well more like the curator of the mind, that is the brain. Why is there one brain and one heart and two lungs, two kidneys and one liver? And why pray does that happen? 
The answer to this complex question lies in the basic embryology. You knew I would say that, didn’t you? Joking aside, that is the truth. Lets look at the brain. It arises from the cephalic end of the neural tube. Grows three vesicles and the first and third vesicles sprout into two more giving us five vesicle formation around by the 35th day of life. These five vesicles then form the basis of the brain structures with: midbrain, hindbrain, pons, cerebellum and the medulla oblongata.  Interesting to all this is at the time of the neural tube formation and the first signals to start the activity of formation is given by a single instructor called the Sonic Hedgehog located on the left side of the notochord.

Sonic Hedgehog
The Sonic Hedgehog binds to the “patched receptors” by inhibiting the patched inhibition of the “smoothened receptors,” which leads to the glial cells activation.
Sonic Hedgehog signaling

The brain as we know it or the Cerebral Cortex with all its “Grey Matter” is actually a later occurrence in-utero when the cell migration takes place.  There are three forms of migration,
Radial Migration of neuronal cells
radial migration of
neuronal cells
the Radial from sub-plate to the cortex, tangential and bipolar. The cells use the “rope” of the differentiated glial cells to climb to the top to replace the older cells and in so doing gain all the stored memories within to take on the job. It is like replacing a goalie in a soccer game. The departing goalie lets the new one know what is going on, who is on the up-and-up and who isn’t. Or in baseball terms a manager booted by the umpire turns his roster over to his vice-manager and then provides a few helpful hints from the hallway of the dug-out. Oh yes!

At birth the infant’s brain has 100 billion neurons with 2,500 connections per neuron. As the baby grows and experiences the world some of these connections will be lost
Brain development
from disuse and others will be gained and at adolescence the connections (Synapses) per neuron are around 15,000.

Lots of  Facebook, Twitter and Linkedin connections wouldn’t you say? The more connections the better armed we are with knowledge!

Oh and if you didn’t ask, here is a bonus answer to a question that hangs in the air. Why do we forget? Simple: We don’t exercise the synaptic control of the connection by feeding it routinely with
Synaptic Connection
repetition and the connection is lost (withers) and so is the content of that connection. Thus the over-developed rut in the brain is the affliction of paranoia and the withered ruts are the lack of remembrances.

The skeptic in all of us will say, "But majority of the people in the universe are right-handed! So how does this left-handed nonsense work there. Elementary my dear Watson, the right handed people are Left-Brain dominant. aren't they? Right but what of those who are deaf-mute who correspond with sign language. What of them? They too young Watson utilize their right hand in signage more than let hand. Hmm, you wonder. Upon this bed of philosophy is a glazed surface of experiential and experimental credibility. Another interesting feature in this left-right issue is the molecule limonene that in its L-mode smells like an orange but the same molecule in its D-mode smells like a lemon. Now go figure! So changing the spin, changes function. The mind is confused but the heart is still into it. Isn't it?

Speaking of the one heart. Oh and what a divine piece of machinery it is. Ask the cardiologists and they will tell you the wonders of this rhythmic musculature that keeps the juice of life flowing. It springs, again speaking embryologically, from the two cardiac tubes that originates from the splanchnic mesoderm. 
Heart development

Heart Molding during development
They merge to form a single cardiac tube that then the cardiac tube convolutes ventrally during the growth and forms five pouches that will form the basis of the atria, ventricles the aorta and the caval veins. (All of this happens through the genetic signals delivered at appropriate time in development, thus space-time is also governed by the DNA!)

For those needing more information, I will direct you to a signature article below: (2). Suffice it is to say that atria collect and the ventricles distribute the blood. A heart that beats an average of 72 per minute will have logged over 3 billion beats in a 80 year lifetime.

One more thing, remember, I said that the Sonic Hedgehog resides to the left of the notochord. The question is why. Why does it reside on the left side only? Is there a left sided conspiracy in the universe (apolitical)?

Interesting that you ask. Turns out, and this will surprise you. That almost all proteins are made up of levorotatory amino acids (L Amino-acids). Let me explain. There is something called chirality in every aspect of nature. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom. And to fulfill the limited lexicon for understanding, an optical isomer or mirror image of a L or D chiral substrate is termed as an “enantiomer”.
Enantiomers

 The proteins have it, the DNA has it and humans have it too in various degrees. And if you were a real stickler about it the atoms and their respective components have it too! So let me start by saying that nature is blossoming with left and right things. For example the nautilus sea shell cork-screws to the right – look at it sometimes and it follows the “golden-ratio” or Phi (Based on the Fibonacci numbers) Now looking back at proteins, as we know that enzymes are also chiral since they are basically preoteins. The enzymes behave like a glove-like cavity which is unique to fit/bind to its substrate. Thus a levo or left rotatory enzyme will have a hard time binding to a right-fitting substrate. (Its like the Democrats and the Republicans) That is why the RNA and DNA have a Dextro-rotatory chirality. The interaction between the amino acids and the RNA is governed by the Ribosome, which makes it a perfect fit/bind. 
So why then is the Sonic hedgehog sitting on the left side of the Henson’s node?  Because its counterpart gene called “activin receptor IIa” resides on the right side to guide the tissue proliferation, while the Sonic Hedgehog determines the “axonal guidance cues” and the “domains of the interneuron and motor neuron progenitors.” Oh nature, what a fabric of beauty it weaves.
Stopping now would leave an empty feeling inside the pit of my stomach and hopefully yours, if you are still there with me, that is. But nevertheless plugging along with this chirality mystery, let us dig deep into the atom and voila, we find that electrons have a left moiety and the muons, protons have a dextrorotatory vision. Even the W and Z bosons are majoring in the disciplines of left and right to keep the fate of the atom and the weak nuclear forces in balance.  A new study in Nature suggests that top quarks have an asymmetric force field counter to the Standard Physics Model. This could be the beginning of another beautiful confounding relationship between rethinking, theorizing and experimenting to understand the very edifice of life and the universe (6). Oh and speaking of the weak nuclear forces the W charge in the atom has a weak dextrorotatory alignment and this is associated with the “Nuclear Decay” as in, Radon Poisoning from the decay of Radioactive Radon and of course the lurking windfall dangers of storing huge quantities of spent nuclear fuels rods (plutonium) that have a constant but extremely long half-life of decay sitting somewhere deep underground the Rocky Mountains, waiting for a fissure or fault in the geological crust to bite us. Ouch! ( http://jedismedicine.blogspot.com/2011/04/radiation-and-humanity.html ) One last question here. Who discovered this left-right stuff anyway. Why of course the one and only Louis Pasteur, a chemist and a microbiologist by trait who confirmed the "germ theory" and was the first to make a vaccine for rabies and anthrax was also the person who discovered through crystallography the chirality of compounds. (enough trivia. lets move on...)

And a truly last point on this for now; Ever notice when going to the major museums, for instance the Louvre or the Metropolitan Museum of Art in NY, how many portrait paintings show the left side of the human face? Aha, got you. The rough estimates are 60:40. Humans are levorotatory inclined in deciphering beauty. Of course the “Golden Ratio” better be present in the facial structure for real “beauty” to be considered as “real beauty.” ( http://jedismedicine.blogspot.com/2010/01/leonardos-temple.html ) But truly take a sampling next time you visit. It will unnerve you, delight you and put you in the zone of circumspection. And if you look even closer at artifacts, they too are left-inclined slightly, majority of the times. Is that a human frailty based on our make up or is it something else? Another question emerges for you to inquire. Accepting an answer without question is akin to accepting the world is flat because that is as far as the eye can see. A conundrum that when answered by Galileo almost cost him his life in the inquisition. ( http://jedismedicine.blogspot.com/2010_08_01_archive.html )

I know, by now you are either cursing or on a path to questioning. But let it not rest in your minds that to question is a human freedom that can never be subjugated by another if we don’t allow it.  Whether on top of the mountain or diving deep in the sea, our thoughts and questions are ours and must remain so till the end. The answers we get from the “Whys” might surprise us into creating more synaptic threads of knowledge and understanding of how the world works.

 References:

1.Shonkoff, J.P., & Phillips, D.A. (Eds). (2000). From Neurons to Neighborhoods: The Science of Early Childhood Development National Academies’ Press.

2. Jiang X, Rowitch DH, Soriano P, McMahon AP, Sucov HM.. (2000). "Fate of the mammalian cardiac neural crest...". Development (Cambridge, England) 127 (8): 1607–16.

3. Charron F, Stein E, Jeong J, McMahon AP, Tessier-Lavigne M (April 2003). "The morphogen sonic hedgehog is an axonal chemoattractant that collaborates with netrin-1 in midline axon guidance". Cell 113 (1): 11–23

4. Dorus S, Anderson JR, Vallender EJ, et al. (2006). "Sonic Hedgehog, a key development gene, experienced intensified molecular evolution in primates". Hum. Mol. Genet. 15 (13): 2031–7.

5. McClintock, Barbara (1950) "The origin and behavior of mutable loci in maize". Proceedings of the National Academy of Sciences. 36:344–55

6. http://www.nature.com/news/2011/110723/full/news.2011.436.html?s=news_rss&utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed%3A+news%2Frss%2Fmost_recent+%28NatureNews+-+Most+recent+articles%29

By:
Parvez Dara, MD FACP
Twitter: JediPD

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