July 10, 2014 | David F. Coppedge

Body Secrets You Never Heard Of

Your body is performing hi-tech processes all the time that (thank goodness) you never have to think about.

The eye in your brain:  Can the brain see without an eye?  A long train of observations with cave fish and artificially blinded birds shows that animals can still respond to light-dark cycles without eyes.  A paper in Current Biology explores the “non-visual photoreceptors” in certain parts of the brain.  In humans, “The adult mammalian pineal is not photoreceptive although it contains opsin,” the paper states.  Much work remains to be done to explore this phenomenon.  “Non-visual photoreception is involved in several other partially overlapping functions: circadian entrainment, pupillary constriction, even (in mammals) fear conditioning,” the article ends.  “Indeed, it is so widely present among the vertebrates that it constitutes a separate sensory modality distinct from vision.

Tear down this wall:  Every time a cell divides, the cell has a massive demolition and reconstruction job on its hands.  The cell nucleus, in particular, has to be dismantled, rebuilt and reorganized.  Another paper in Current Biology, “Nuclear Envelope Breakdown: Actin’ Quick to Tear Down the Wall,” describes the latest findings about this process.  “Nuclear envelope breakdown in metazoan cells is thought to be facilitated by microtubules, which pull on the nuclear membranes,” the authors say. “Unexpectedly, an F-actin meshwork helps to tear down the large nucleus … and to prevent chromosome loss in meiosis.”  You wouldn’t want to lose chromosomes.  That would be bad.  The daughter cells each get a brand new nucleus, complete with fresh new copies of chromosomes and nuclear pore complexes (large “portals” in the nuclear membrane) that control traffic in and out.

Error correction and prevention:  One of the most striking evidences of intelligent design in genetics is the presence of factories of molecular machines in the nucleus devoted to correcting errors.  This underscores the fact that genes constitute a coded language where accuracy is important.  One of the repair robots that finds and corrects typos is named Srs2 helicase, described in this week’s Nature.  Researchers from New York University School of Medicine and Yale “document a new, unexpected genome maintenance role” for this molecular machine.  It’s actually a backup for another editing machine named RNase H2.  When that machine is inactivated for any reason, Srs2 attaches to a nick produced by another machine at the typo site; there, it unwinds a stretch of DNA, calls in another machine to extract the error, leaving a gap in preparation for another machine to fill in the correct letter.  It’s actually a lot more complicated, but this gives a hint of the care given to DNA to maintain genomic integrity.

Your skin smells good:  A friend’s nose might appreciate your clean skin, but our subtitle means something else: there are odor receptors in your skin.  New Scientist describes how these odor receptors work: “How does your skin smell?  Pretty well, as it turns out, thanks to receptors dotted all over you,” Bob Roehr begins the article.  “What’s more, they could help you heal.”  These olfactory receptors in the skin don’t send messages to the brain.  Instead, they trigger cells to divide and migrate, signs of repair processes.  These “finely-tuned” receptors, responding to specific chemicals, might explain why some skin care products can help heal wounds or make your skin smooth and younger-looking.

New twist on vision:  Many have heard that rhodopsin is the chemical in our rods and cones that responds to light.  Most of us, though, had not heard that rhodopsin, like other things, has an optimal temperature range.  PNAS published a paper about “unusual kinetics of thermal decay of dim-light photoreceptors in vertebrate vision.”  Normally, the higher the temperature, the more the noise.  Rhodopsin, however, has an unusual molecular response to higher temperature that allows it to maintain good vision in spite of the thermal noise problem.

Dealing with distractions:  In our busy culture, many of us have to multitask.  Science Daily sets up a common problem: “You are trying to dial a phone number from memory … you have to concentrate … then someone starts shouting out other numbers nearby. In a situation like that, your brain must ignore the distraction as best it can so as not to lose vital information from its working memory.”  Even though we must exercise will power to concentrate, the brain helps us.  Experiments with rhesus monkeys having to recall dots on a screen found that two parts of the brain back each other up:

Measurements of the electrical activity of nerve cells in two key areas of the brain showed a surprising result: nerve cells in the prefrontal cortex signaled the distraction while it was being presented, but immediately restored the remembered information (the number of dots) once the distraction was switched off.  In contrast, nerve cells in the parietal cortex were unimpressed by the distraction and reliably transmitted the information about the correct number of dots.

This implies that the brain includes a fall-back position to recall the desired information without completely ignoring the distracting information.  “These findings provide important clues about the strategies and division of labor among different parts of the brain when it comes to using the working memory,” the article concluded, adding that “the researchers were surprised” by the discovery.  “The memory-storage tasks and the strategies of each brain area are distributed differently from what we expected.”

Memory champNature just published a paper about a molecular machine in neurons that is important for many functions, especially memory.  Called NMDA, its job is to open ion channels in the membrane after validating inputs. In a companion article in Nature, Stroebel and Paoletti say, “Two structures of almost complete receptors reveal the intricate complexity of these large, multi-domain molecular machines.”  To bypass a lot of technical jargon, let’s just say that NMDA is very complex, and when it doesn’t work right, people can suffer from epilepsy, retardation or schizophrenia.  If you aren’t suffering from those right now, be glad your NMDA’s are working just fine.

These items are only the tip of a vast iceberg.  Take any system in the body: circulatory, nervous, immune, whatever – it can be subdivided into subsystems, and those can be further subdivided all the way down to cells and molecules.  At every level, we see incredibly intricate tuning, synchronization, and functional complexity.  These are hallmarks of intelligent design.  Volcanoes and landslides don’t have these characteristics.  They may be “designed” at a very low level (as undirected outworkings of natural laws), but they lack the functional information that shows intentional, goal-directed planning for higher purposes than just obeying natural law.  Moreover, this information functions at multiple hierarchical levels, like elements of a vast computer network.  You can drop a computer and it will obey natural laws, but its true intelligent design is revealed in its fulfillment of its purpose: to perform information processing.  A human body can also fall by gravity.  That’s a real tragedy.  A body is not just a rock in a landslide.  It is meant to house a soul that can glorify its Creator by performing its intended purposes: to love God, love others, and do His will on earth as it is in heaven.  Start by reading the Operations Manual.





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