December 9, 2017 | David F. Coppedge

Human Body Wonders to Amaze Their Inhabitants

There’s more going on under your skin than you can possibly comprehend.

What Goes On in the Blink of an Eye?

Blinking does not just lubricate the eye: it resets its pointing. That’s the finding of a paper in Nature Scientific Reports. Scientists have known for many years that eyes undergo constant involuntary movements, called microsaccades. These prevent rods and cones from saturating and help with pointing. Now, they find another type of movement that occurs during an eye blink when the eye can’t see where to point. They call it blink-associated resetting movement, or BARM. It’s like having coarse tuning in addition to fine tuning:

Amazing FactsWe show here that fixational BARMs are functionally distinct and complementary to microsaccades in the following way: First, they compensate for large fixational error more efficiently than microsaccades, secondly, their probability to be executed in eccentric eye positions is higher, and thirdly, they reset the eyes into a position zone that is broader as compared to microsaccades. This suggests that BARMs help to keep the eyes in a working range wherein microsaccades guarantee high acuity vision. Moreover, we establish that fixational BARMs operate in a retina-centric frame.

Rods Contribute to Bright Light Vision

The textbooks tell us that the rods in the retina, which are monochromatic and sensitive to dim light, operate in dim light, and cones, which sense color, are at work in bright light. An article from Tübingen University reports new findings that show that rods don’t tune out when the lights come on. “They were thought to become useless as light levels increase, while vision in daylight conditions is based on cone photoreceptors,” the article begins. “The new study — published in Nature Communications — shows that rod function can even increase in bright light.” This discovery will require more investigation to understand, and it may lead to better treatments for the visually impaired. Scientists understanding of vision must be incomplete, now that it appears that rods are not blinded by bright light. “Most surprisingly, their contribution even increases when the daylight becomes brighter, up to the brightest light levels that would ever be encountered in natural environs.

Split Brains Can Still Communicate

The corpus callosum is a “bridge” between the left and right sides of the brain. In rare cases, it can be injured or surgically severed to treat conditions like epilepsy. Are the hemispheres left out of touch? Scientists have known that communication can still proceed in such patients. A new paper in PNAS finds that the brain has workarounds – other pathways around the bridge.

The relation between structural and functional connectivity has profound implications for our understanding of cerebral physiology and cognitive neuroscience. Yet, this relation remains incompletely understood. Cases in which the corpus callosum is sectioned for medical reasons provide a unique opportunity to study this question. We report functional connectivity assessed before and after surgical section of the corpus callosum, including multiyear follow-up in a limited subsample. Our results demonstrate a causal role for the corpus callosum in maintaining functional connectivity between the hemispheres. Additionally, comparison of results obtained in complete vs. partial callosotomy demonstrate that polysynaptic connections also play a role in maintaining interhemispheric functional connectivity.

Update 12/15/17: Here’s a case worth pondering: Medical Xpress reports “The mysterious case of the boy missing most of his visual cortex who can see anyway.” A team from Monash University in Australia studied “the brain of a seven-year-old boy who was missing most of his visual cortex but could still see—the first such case ever known.” A module of the cortex usually involved in motion detection was apparently repurposed by his brain to function as a vision center. Such amazing plasticity would seem to indicate that sensory ability is not a function of brain mass, overthrowing a foundational assumption of biological racism dating to the 19th century that was obsessed with brain size.

Tough Guy or Softy?

Actually, humans have both a sensitive side and a tough side. Speaking of tissues, they can be soft and strong, says Collagen fibers connect cells into a network that, when stretched, resists further stretching. Physiologists used to think that cells under tension maintained their initial volume. New work shows that cells can squeeze out water into the network when stretched, and then gain it back when tension is released. They can lose volume up to 50% in this way. “This contradicts the prevailing paradigm that although such soft biological tissue can deform significantly, its volume remains unchanged,” said Edoardo Mazza of ETH Zurich. What this means for you is that skin-so-soft can actually take quite a beating. It also explains the adaptability to stress of other soft biological tissues, including the amniotic sac that protects a developing baby.

The Achilles Tendon – A Weightlifter

The Achilles tendon above the heel, named for the legendary Greek warrior, is the largest and strongest tendon in the body. Science Daily says it can withstand 900 kilograms (2,000 pounds) when running. Even though it is prone to injuries, it can handle a great deal of wear and abuse (think of weightlifters doing calf raises). There’s actually more than one tendon involved. Part of its strength comes from its connectivity to three different muscles with different loads. “Studies with the measurement of Achilles tendon forces have proved that loading may not be distributed evenly throughout the entire cross-sectional area of the tendon,” the article says. “This is possible because the Achilles serves as a common tendon for three calf muscles, which all have different properties and functions.” The article then describes the soleus, lateral gastrocnemius, and medial gastrocnemius muscles and their attachments to subtendons of the Achilles.

More Reasons to Breastfeed the Baby

Many benefits of natural breast milk have been discovered. Some of them are mentioned in chapter 2 of the new book by Richter and Coppedge, Spacecraft Earth: A Guide for Passengers. Another benefit was reported by FARE, Food Allergy Relief and Education: breast milk appears to prevent allergies. Certain proteins in breast milk help prime baby for protection from allergens. The findings from experiments on mice are probably applicable to humans as well:

The mouse study found that when a nursing mother is exposed to a food protein, her milk contains complexes of the food protein combined with her antibodies, which are transferred to the offspring through breastfeeding. Aided by a protein in the offspring’s gut lining and some immune cells, the food protein-antibody complexes are taken up and introduced to the offspring’s developing immune system, triggering the production of protective cells that suppress allergic reactions to the food. These protective cells persist after antibodies from the mother are gone, promoting long-term tolerance to the food.

Your Ceramic Toolkit, the Envy of Materials Scientists

Scientists are envious of nature’s hardest minerals, Science Daily says. Among the enviable crack-resistant substances they would like to imitate is one we often take for granted: tooth enamel. It works like some other competing hard biological ceramics:

Natural composites are common. Examples include nacre (mother-of-pearl), tooth enamel, bamboo and the dactyl clubs of mantis shrimp, all of which are nanoscale arrangements of hard platelets connected by soft matrix materials and arranged in overlapping brick-and-mortar, bouligand or other architectures.

They work because the hard parts are strong enough to take a beating and flexible enough (due to the soft matrix) to distribute stress throughout the material. When they fracture, they’re often able to distribute or limit the damage without failing entirely.

The Best of All Possible Bodies?

The meaning of this sentence from Science Daily depends on how you look at it: “Newly emerging trends in data suggests humans may have reached their maximum limits for height, lifespan and physical performance.” So is the glass half-empty or half-full? Actually, any engineering product is a series of compromises attempting to optimize the whole. When you look at a body at its best, given the demands of a wide variety of situations it must perform in, it seems hard to improve on it.

A Law of Media we often observe at CEH is that Darwinspeak is inversely proportional to the detail in a scientific paper. How could evolutionists account for the things reported above? This is not just design, it is over-the-top design.

Biblical creationists believe that humans were designed to live forever, but now we live in a cursed world after Adam’s sin. The curse affects all nature, including the human body, which is subject to disease, disability, and death. Nevertheless, the Apostle Paul said to the people of Lystra, “He did not leave himself without witness” (Acts 14:17). The author of Psalm 139 wondered with awe at how we are knit together in the womb, exclaiming that we are “fearfully and wonderfully made” (Psalm 139:13). We can honor God with the body. Paul told Timothy, “For everything created by God is good, and nothing is to be rejected if it is received with thanksgiving, for it is made holy by the word of God and prayer” (I Timothy 4:4-5). In spite of weaknesses, the body is incredibly engineered and usually works incredibly well. Take care of your “spacesuit” as Richter calls it, as you ride Spacecraft Earth through the universe. And whenever you enjoy a pleasure or comfort, such as delicious food, give thanks to the Creator who made it.

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