Human Body Curiosities
Things you didn’t know about your ambulatory vessel, and things you may have wondered about.
Why do we get hiccups? Once in a rare while, a scientific paper will actually explore something everybody wants to know: what are hiccups, and why do we get them? In PLoS One, the word jumps out of the jargon: “Analysis of factors associated with hiccups based on the Japanese Adverse Drug Event Report database.” This paper by Japanese scientists is primarily concerned about medications that induce hiccups, especially during chemotherapy. For some reason, males tend to get hiccups more than females, the paper says.
A lay article in Medical Xpress came out about the same time. The scientific name is “singultus,” an expert on hiccups tells us. It’s not a disease, but a symptom of some other cause, he says. “And we all have them, even before we are born.” They are described as “an involuntary contraction of the diaphragm (the muscle that separates your chest from your abdomen ), followed by the sudden closure of the vocal chords, which produces the ‘hic’ sound.” In rare cases they can be chronic; most cases last just a few minutes. Unfortunately, there is no cure, but some of the home remedies actually might help if they stimulate the vagus nerve. Neither source mentions whether hiccups have a function. Perhaps they are just warning calls of some underlying condition.
How old can couples have a baby? This article on Live Science begins with a photo of George (age 55) and Amal (age 39) Clooney, expecting twins this summer. Having children later in life is a trend in America, Rachael Rettner says; fortunately, she has some good news. If the science is correct, older mothers may live longer and have reduced risk of cancer; the children of older fathers may live longer. Older couples seem to have a greater chance of bearing twins. However, there are risks, too: possible higher risk of Down syndrome, autism, or psychiatric problems in the children, and problems with pregnancy. These kinds of studies are often overturned, so none of them should be taken as definitive findings of science. The average age for parents’ first children are in the mid-twenties.
How does a baby in the womb grow tubes? From a single zygote, a baby grows a digestive tract with many feet of tubular processes. How does that happen? A partial answer is published in PNAS. Some of it has to do with signals from BMPs (bone morphogenetic proteins), that control buckling forces as loops in the intestine grow and push on each other. At least it happens that way in chicks (baby birds, that is). “The present work identifies BMP signaling as a key pathway in controlling looping of the small intestine, a process driven by mechanical buckling due to elongation of the intestine against the constraint of a neighboring tissue, the dorsal mesentery.” Surely there is much more going on than that. How does a clump of cells start growing tubes? This paper doesn’t say.
Why are we right or left handed? Certainly our handedness is one of the most distinctive things about us, with southpaws having to compensate in a predominantly right-handed world. A fundamental change in understanding about handedness is coming, says Science Daily. Biophysicists “have demonstrated that gene activity in the spinal cord is asymmetrical already in the womb.” The decision in the 8th week of gestation appears to come from epigenetic influences based on environmental factors. So far, this sounds like only a very paltry, preliminary answer to the question. Speaking of pregnancy, this opening paragraph in “Secrets of Life in a Spoonful of Blood” by Claire Ainsworth in Nature deserves a pulpit and a microphone:
Life starts with a puzzle. Out of sight in a mother’s womb, 3 billion letters of DNA code somehow turn into 3D bodies, all in the space of a mere 40 weeks. Fetuses form eyes, brains, hearts, fingers and toes — in processes that are meticulously coordinated in both time and space. Biologists have pieced together parts of this puzzle, but many gaps remain.
Why do we have smell receptors in the heart? That’s right; we have olfactory receptors in our hearts, believe it or not. Why? Science Daily says, “Researchers have for the first time identified the function of olfactory receptors in the human heart muscle, such as are also present in the nose.” We’re all dying to know. Well, at least one of the receptor types attaches to fatty acids in the bloodstream. When triggered, “the heart rate and the force of muscular contraction are reduced.” There must be a reason for this. What they’re finding may have treatment implications for diabetes patients, the article says.
How does tooth enamel grow? The growth of minerals in teeth is poorly understood, PNAS says, but the process involves “intrinsically disordered proteins.” Researchers found that a particular protein motif “is shown to be essential for organization of the enamel organic matrix and for proper organization of hydroxyapatite crystallites into the compact bundles that determine the structure and mechanical resistance of enamel.” Whatever is going on “involves a short linear amino acid motif that is evolutionarily conserved from the first tetrapods to man.”
How does an eye develop? Scientists are studying the development of eyes in zebrafish to learn about the amazing sequence of events in an egg or womb that result in vision. Words fail to describe what goes on. Here’s just a quick glimpse from Phys.org, as Sarah Wong writes on “Seeing the world through fresh eyes” –
There are many different structures in our eyes that work in conjunction to allow us to see. These structures are strikingly similar between different species, from zebrafish to humans. The growth of ocular tissues must be tightly controlled in order to maintain the correct eye size and shape that allow us to see. This tight regulation has intrigued developmental biologists for decades.
The lens of the eye focuses incoming light on the retina, which then converts the light into electrical signals allowing us to see. Two distinct cell types comprise the lens: epithelial cells, which cover the front, or anterior, portion of the lens, and fiber cells, which populate the back, or posterior, portion. It has been shown that epithelial cells proliferate in the anterior half of the lens and move towards the posterior half, differentiating, or transforming, into fiber cells when they reach the equator between the two halves….
Why do we get sore after exercise? Muscle soreness may be a protective response, telling you to slow down. That’s the upshot of an article in Medical Xpress, “Research uncovers mechanism, protective purpose of muscle soreness following exercise.” Physiologists knew what happened before, but nobody knew why. “The soreness a person feels is the body saying it is fatigued, that the muscles are vulnerable, and it’s time to rest.”
Is stress all bad? We usually hear that stress kills, but Science Daily invites curiosity with this headline: “What doesn’t kill you makes you stronger: Research identifies cellular recycling process linked to beneficial effects of enduring mild stress.” Further reading, though, shows that research involved roundworms. Those worms subjected to temporary heat stress seemed to become more resilient to later stresses. The researchers at Sanford Burnham Prebys Medical Discovery Institute think that the same principles apply to human cells.
Why do men go bald? Most middle-aged and senior men would like to fight the fate of the fading pate. A study reported by Science Daily examined genetic markers that seem to predispose some men to ‘male pattern baldness’ more than others. Unfortunately, science is still a long way off from answers or treatments.
Can older adults still exercise? The old principle “Use it or lose it” seems sound. The American Geriatrics Society says that “Older Adults Who Exercise Regularly May Lower their Chances for Developing Severe Mobility Problems.” A study of 1,635 seniors aged 70 to 89 at risk of disability showed that the group that walked and practiced balance training suffered fewer severe mobility problems, although time did take its toll.
Why don’t animals write poetry? Language is perhaps the greatest human distinctive. Medical Xpress asks, “Is the human brain hardwired to appreciate poetry?” This seems to be a matter beyond the capabilities of science. Researchers publishing in Frontiers of Psychology found the obvious: people seem to have a liking for rhymes and meter. The brain seems able to connect with the thoughts of a poem even before understanding it, but that’s about it. What the blinking lights mean on the brain electrodes is anyone’s guess.
Update 2/24/17: How do butterflies get in our stomach? (The Conversation). It’s a figure of speech, of course, but Bradley Elliott proposes to explain the fluttery semi-nauseous feeling we get when nervous, such as when rising to give a speech. It has to do with “clever body systems,” he says. Our autonomic nervous system helps to prepare us for what it thinks is about to happen. It shunts blood to the muscles and away from the digestive system, causing the fluttery feeling. Whether this provides us with an “evolutionary advantage” as Elliott claims is a topic for debate.
There’s more going on under our skins than we can possibly imagine. It’s a terrible shame to waste a body and mind on vain things. It’s insulting to our Maker to mistreat this great gift we have. Your body may not be working perfectly, but the parts that do work are worthy of protecting and nourishing. Is there any pleasure, any joy? Give thanks to the Creator for even the little things. Think of those ALS patients who have lost all movement yet still say they are happy (2/05/17). We so often take health for granted. Even Christians at prayer meetings often spend more time requesting prayer about sickness than praising God for health. “Does anyone have a prayer request?” the leader asks, and like Pavlov dogs, out comes the sick list. Let’s get out of that habit and spend more time in thanksgiving. By all means, pray about major things, but not every cold and itch needs to be brought up. Be humble, and surround your physical request with joyful thanks. Those who trust in the Lord Jesus have an amazing upgrade – Body 2.0 — coming in heaven. If God can make a body work this good in a fallen, disobedient world, just imagine how beautiful and perfect our dwellings can be in the new heavens and new earth.