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Every Month: a Review of Major Teaching Points

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A Power Program for Student Review

A Review of Teaching Highlights from Last Month

The 6-Month Program

  1. Biophysics Of Obesity
  2. Obesity...Cholesterol...Heart...Stroke
  3. Obesity...The Metabolic Syndrome
  4. Obesity...Insulin Resistance...Diabetes
  5. Diabetes Complications: Glycoproteinopathies
  6. Obesity...Feeling Sick and Liverish
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The developed world is suffering major epidemics of self-inflicted wounds.

They began in the middle of the last century with heart attacks. Jogging and fitness were the popular reactions, as cholesterol and coronary became household words. We must now add visceral obesity with its metabolic lesions to the list. These lethal threats, their management and their prevention, are the focus of this online open teaching program, and the topic this month is fitness.

Reaching for a keyboard or cookie is a complicated action: mechanically, neurologically and metabolically. The arm’s motor nerves are firing continuously while being modified throughout the action for a smooth outreach and return. It’s done with stored muscle energy, fast neurone shortcuts and multiple sensory feedback checkpoints. And everything happens reflexly without brain input from you, once the order is given.

Physical activity means that muscle fibers are contracting. They shorten and bulk up, pull their bone attachments around joints, and move a limb, using muscle’s energy. The initial energy comes from sugar stored in muscle cells and later from circulating fatty acids released by those pesky fat stores.

All this activity needs oxygen, which generates carbon dioxide and water and waste. A circulation is needed (heart, arteries, veins and lungs) to meet muscle demands and remove the waste of its work. Several muscle disorders and the common cerebral dementias result from metabolic clutter collecting and choking cell machinery.

Physical training conditions muscle sets into coordinated, skilled and sustained performances, in Olympic parlance: faster, stronger, higher. All these activities take place in the body at a macro level of understanding. Today’s research however, focuses understanding on the micro level of cellular chemistry and exercise. It involves a process called autophagy.

Pronounced ‘otto-fa-jee’, it means literally, self-digestion, a name that was devised before the nature of the process was fully understood. Autophagy is actually cell housecleaning after the accumulation of clutter from the day’s work. It takes place regularly in all tissues, usually at the end of the work day, so mostly at night. It also takes place any time in muscle whenever energy levels dip and there’s a need to refuel.

Autophagy is an elegant process. When cell energy levels fall, autophagy’s chemical conductor rises from the cell juice to tap on the wall of the cell nucleus (which houses genes and cell controls). On signal, the nucleus activates dozens of its contained genes and produces a flow of identical protein molecules called Ubiquitins. They are intent on getting out of the nucleus and into the cluttered juice of the fuel-starved cell.

Ubiquitins perform two chores out in the cell juice. First, one set of them position themselves around all cell walls to link up and form a collecting net. Second, another set forms a tiny recycling center (called a lysosome) that waits to process everything gathered up in the net. So autophagy can capture loose molecules for energy…sugars, fatty acids and amino acids.

In its sweep from the cell walls, the net also gathers up production errors and broken bits of cell machinery. The loaded net next fuses with its cousins forming the lysosome to salvage what can be re-used and burn up everything else. It’s a daily cleansing that provides each cell with fresh energy and machinery repairs. Worksite  clutter is eliminated, mostly as carbon dioxide and water, which migrate harmlessly into the circulation to be lost through lungs or kidneys.

The brain benefits indirectly but immediately from exercise in two ways: First, thinking is sharpened in New Brain (the cortex) by circulating catecholamines: hormones of fight/flight. Second, feelings are improved down deep in Old Brain from the release of neurotransmitters, called dopamine, that lift the mood and instill confidence. We’re talking primitive survival here.

So exercise awakens genes that houseclean and refresh all body cells. And new research reveals It even effects the fat cells. Ten healthy men were evaluated after 3 months of serious exercise for an hour a day, 5 days a week. Researchers found a metabolic effect in the genes of fat tissue cells, called adipocytes. Their activation not only improved glucose tolerance but mitigated the cholesterol effects of a dirty diet. The Take-Away ? Exercise also shapes up those pesky, bulging fat stores.

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