Cumberland Times-News

Bob Doyle - Astronomy

December 22, 2012

Brain and stomach have a connection

Your hunger and desire to eat goes back to early humans who had no assured supply of food. Back then, humans ate to build up a surplus (in the form of fat) in the event of famine.

Today we have more than a dozen neurotransmitters to nudge you towards eating (raising your weight) and a similar number of neurotransmitters to allay hunger (lowering your weight). A neurotransmitter is a chemical that helps transmit signals between the synapses (gaps between your neurons)that send messages to other neurons.

Your three-pound brain has about a hundred billion neurons and supporting glial cells. The neurons form many different groups, each focused on a different function of your body. Each neuron can receive signals from as many as two hundred thousand other neurons.

The electrical signals flow down the axons (long skinny part of neurons) at car interstate speeds. Most neurons communicate with other neurons in the brain. A small fraction of neurons send signals out to your spinal cord to cause your muscles to contract.

Returning to weight regulation, our neurons work together to keep us at a certain weight or “set point.”

When you eat less so your weight drops below your “set point,” your brain lowers your metabolic rate (energy needed to keep all your vital systems going).

This tendency will sabotage most diets. Then eating less results in no change to your weight. When you eat more, your brain tend to increase your metabolic rate to absorb some of those added calories.

   The hormone leptin is produced by fat cells. Leptin is released into the blood telling your body its fat level as well as indicating how the fat levels are changing. When there is less body fat, less leptin is released, telling your body to get more energy (in the form of food).

But when your body fat levels are high, more leptin is released and you don’t feel hungry.

Leptin receptors in your brain are in your hypothalamus, a brain region that regulates body temperature and sexual urges. Leptin also works in other parts of your brain, influencing your metabolism and regulates fat storage.

   Insulin is another hormone that is sensitive to stored body fat. Insulin is produced by the pancreas after meals. In the blood stream, insulin instructs cells to reduce the glucose going into the brain and to store energy.

Lean animals have lower levels of insulin than fat animals. Leptin level is a good measure of subcutaneous fat (fat near the skin) while insulin indicates the visceral fat that is distributed around your organs.

People with a lot of visceral fat are at greater risk for diabetes, high blood pressure and cardiovascular disease. Those of us with fat arms, fat thighs or calves (subcutaneous fat) have less risk than those of us with “beer bellies” (visceral fat). To have a “beer belly,” you don’t have to be a big beer drinker.

Other messengers can act to alter our appetites. Fatty acids and the hormone peptide YY seem to reduce eating while the hormone ghrelin, released around mealtime, increases hunger and food consumption.

For more information about weight regulation, read “Welcome To Your Brain,” a 2008 book by Sandra Aamodt and Sam Wang, both experts in neuroscience.

SKY SIGHTS AHEAD: The moon will be full on Friday, December 28 so there will be plenty of evening moonlight through the end of the year.

The nearly full moon will appear close to the planet Jupiter this Tuesday evening. Venus is a brilliant sight low in the 6:30 a.m. dawn.

Well above Venus at dawn is the planet Saturn. Saturn is then high enough for good telescopic viewing of its rings through modest telescopes with magnification of 30 and over.

Our 2013 Sky Sights features the sun’s positions along the zodiac, dates of the moon’s key phases (evening half full and full), when and where to spot the five bright planets and sunrise and sunset every 10 days for a number of Tri-State towns.

You can get a free copy of 2013 Sky Sights through the mail by leaving your name and mailing address on my voice mail at (301) 687-7799 or sending me an email with your name and mailing address. 2013 Sky Sights will also be posted on the FSU website early next year.

Bob Doyle invites any readers comments and questions. E-mail him at rdoyle@frostburg.edu . He is available as a speaker on his column topics.

1
Text Only
Bob Doyle - Astronomy
  • It’s hotter here than in D.C. or Baltimore

    At this time of the year, the weather is a frequent subject of conversation, particularly the temperatures. We are now in the “Dog Days,” usually the hottest days of the year. The term comes from our sun appearing to be near the “Dog Star” (Sirius) and the “Little Dog Star” (Procyon). In reality, the sun is now about 94.5 million miles away while Sirius is 8.6 light years away with Procyon at 11 light years distance. Sunlight takes only 507 seconds to reach us, while the two dog stars’ light takes about a decade to travel to our eyes. So our sun is in the same direction (but not distance) as these two bright winter evening stars.

    July 20, 2014

  • Fronts, highs, lows determine weather

    Weather news on television and internet focus on violent weather, extreme temperatures and flooding.

    July 13, 2014

  • A long and winding road faces our food

    Last week’s column dealt with organs you can do without, our DNA (molecular blueprint for our bodies) and hair. My reference is “Body: Discover What’s Beneath Your Skin,” a Miles Kelly Book, written by John Farndon and Nicki Lampon and published in 2010. This column will consider finger and toe nails, breathing and coughing, saliva, mucus and your food’s long and torturous journey. Most cities and mid sized towns have nail shops where you can have your finger nails and toe nails adorned. Nail painting can be traced back 5,000 years.

    July 6, 2014

  • Here’s a look at what goes on inside you

    In high school, my favorite science course was biology. I can remember Mr. Munley in his wheelchair. Our class went on a field trip to the University of Miami Medical School where we saw the cadavers used by the medical students.

    June 28, 2014

  • Moon-watching easy when you know how

    Long before the first writing (scratches on clay tablets) appeared, our early ancestors noticed that the moon went through a regular cycle of shapes in about 30 days.

    June 21, 2014

  • Here’s how you can tell the stars, planets

    How can one tell one star from another at night? It’s a matter of knowing the sky areas (constellations).

    June 15, 2014

  • Smithsonian guide to stars is a good one

    At a local book store, I yielded to temptation and bought “Stars and Planets,” a Smithsonian Nature Guide written by four authors. Dinwoodie, Gater, Sparrow and Stott. It’s another Dorling Kindersley product with ISBN 978-0-7566-9040-3 and a 2012 copyright. “Stars and Planets” is a trade size paperback that is beautifully illustrated with appealing diagrams. “Stars and Planets” begins with the biggest topic, the Universe. There is a striking visual showing the known universe on the hugest scale, a delicate lacework of superclusters of galaxies with large voids. It resembles a bubble bath!

    June 8, 2014

  • Think a little more and be less frazzled

    Last Sunday’s column dealt with using technology carefully in education. What about technology in everyday life? There is a marvelous book “The Thinking Life,” by P.M. Forni, of The Johns Hopkins University which addresses this issue as well as timeless suggestions for living by Greek and Roman thinkers. “The Thinking Life: How To Thrive in the Age of Distraction” was published by St. Martin’s Press in 2011 with ISBN 978-0-312-62571-9. Dr. Forni also wrote “Choosing Civility” and “The Civility Solution”.

    May 25, 2014

  • Technology helps with learning, but take care

    Since I have been involved in teaching, two different technologies have been applied to learning at the secondary and collegiate level. The first was video (from videocassettes to DVDs) where a student or class might watch a presentation of some historical event, or a set of scientific principles or even a simulated exploration of the human body.

    May 18, 2014

  • Here are numbers that apply in our lives

    One of the best exercises is walking. Cardiologists suggest that each of us walk 10,000 steps per day. Assume each step is 0.5 meters or 19.7 inches. Then 10,000 steps would cover 5,000 meters or 3.11 miles. But studies find that the average American (from age 4 and up) takes only 2,000 steps/day or 1 kilometer.

    May 11, 2014

Latest news
Facebook
Must Read
House Ads