Medical School: Basic Sciences and other musings

Basic Sciences 

The first two years of medical school are devoted exclusively to academic classroom work and parses the time among a series of courses in basic life sciences, with emphasis on the biology, physiology and patho-physiology of the human being.

The reason for taking pre-med courses in college and the droll subjects of Organic Chemistry, Physical Chemistry, Physics, as well as the dreaded math courses of Algebra, Calculus and Statistics becomes crystal clear when the student is exposed to the basic science program in medical school.

One cannot go forward with life sciences, or even begin to theorize or philosophize about life without this critical background.

Slowly but surely the reason for studying molecules and equations begins to make sense at the next level of being able to understand Biochemistry, Microbiology, Pharmacology; then by blending in Gross Anatomy, Genetics, Embryology, Histology, and Epidemiology the student begins to apply his background to better understand how the body functions, but more importantly then how it fails to do so.

The agenda is a very difficult, highly concentrated discipline requiring tedious hours of homework.

But once it ultimately dawned on me that the “organic” in chemistry referred to the “life” in the organism, I was at least now able to apply molecular science to real life. There was finally a light shining at the end of the scholastic preparatory tunnel,

One of the most fascinating concepts for me was the explanation as to how life on earth shifted from anaerobic to aerobic metabolism at the single or primitive multi-cellular level.

The emergence of cyanobacteria, followed then by blue green algae and their subsequent ability to saturate the earth’s atmosphere with oxygen, facilitated the emergence of organisms that developed internal systems able to efficiently utilize oxygen as the basic fuel to drive energy production at the cellular level.

This was the change that caused the explosion of life as we have come to know it and allowed the planet to evolve life forms above the level of simple units of life such as yeast, fungi or anaerobic bacteria.

It changed the characteristics of the planet forever.

The difference lies simply in cellular efficiencies.

Anaerobic organisms have limited ability to utilize oxygen, being only a primitive life form that could succeed without relying on oxygen. They existed on earth far before more advanced forms of life.

Their energy production is paled by the energy production capabilities of the aerobic organism that can use oxygen to convert stored sugar, carbohydrate and fat at a rate 90% more efficient than that of the less efficient anaerobe.

This energy production takes place at the level of the intracellular organelle known as the mitochondria, a structure that some evolutionary scientists believe might at one time evolved from the symbiotic incorporation of a specialized oxygen utilizing bacteria into the larger structure of a less efficient parasitizing, or conversely, parasitized cell.

This energy production happens in a unique metabolic cellular pathway known as the Krebs cycle.

Regardless of how it happened, the result was the ability of life on earth to evolve into much more complex forms that allowed the emergence of the complex diversity of animal and plant life; including humans and the rest of life that surrounds us.

What many people fail to comprehend is the very fine line between any of earth’s organism’s success or failure and just how uniquely oxidative metabolism affects us all simply because by its very definition it is responsible for both our life as well as for our death.

The oxygen saturation of the earth’s atmosphere is 21%.

Most of the rest at 78% is Nitrogen, which is inert, and then 1% of the residual is argon, water vapor and small amounts of carbon dioxide, which itself is an end product of oxidative metabolism.

At oxygen levels of 7% all oxidative life on earth would cease to exist.

This explains why a Mount Everest climber requires an acclimatization period to increase his red blood cell counts; ergo his oxygen carrying capacity, as well as needing supplemental oxygen canisters to succeed at or near the peak.

The oxygen content of air at this height is so low, that if this climber were dropped out of a helicopter on the summit, he would immediately die of asphyxiation. The same thing would happen if cabin pressure in a Boeing 777 failed at 35,000 feet; not to mention the temperature of -60 Fahrenheit. Your last breath would be frozen to your porcelain face.

Paradoxically, too much oxygen is also harmful. At saturation levels higher than 50%; with chronic exposure to it, a person would die of oxygen toxicity because these higher levels would destroy his organs by literally burning them up like a match put to a piece of dry paper.

It is thus a pathetic fallacy that an NFL football player can improve his oxygen debt after a sudden sprint; or even his overall performance in general by sitting on the sidelines and getting a hit of pure O2.

In fact, if he breathed pure oxygen throughout the game he would not survive to the end of it, even though nevertheless the O2 sucking scene of the weekend warrior huffing and puffing on that sideline bench evokes sentiments of fantastic, fabulous macho bravado.

How about fixing this problem by just doing a few more wind sprints in practice instead?

One must realize of course that this is a chicken and egg phenomenon because life as we know it evolved in Earth’s atmosphere only because this atmosphere was already there. A different gas mix may have produced a different outcome, an altogether different panoply of life; or possibly no life at all.

It is also a fact that a significant part of the aging process is because of oxygen or free oxygen radicals causing a long slow process of tissue damage resulting in the subsequent accumulation of inert, harmful intracellular material; otherwise known as microscopic non-recyclable sludge.

This is exactly what happens when iron is exposed to air. It rusts.

It is this potential harm of oxidation that fuels the current hysterical concept behind the multi-billion-dollar business scams that focus on the fabulous but expensive anti-oxidant products that can supposedly keep a person young and beautiful forever.

Trust me. Do not waste money on these products of false hope. It is not a few hyped up, useless pharmaceuticals or topical emollients; but rather genetics, environment and a bit of good luck that really plays into how gracefully or not we all age as well as for how old we can ultimately live.

This is also why, when patients complain to me that they are not enjoying their Golden Years because they are slowly falling apart, or because their spouse has died; I marvel that they have been succored into buying the myth of the retirement propaganda campaign. It is a myth rooted in the unrealistic concept that a person will be able to do the same things he did at age 70 or 80 that he could do at age 30.

I suggest instead that the retirement years should be better termed the Iron Age. It would be wiser to spend ones’ time or money on recreational fun when young than to waste it later, on anti-aging products, face lifts or in the fruitless search for perpetual youth.

I have taken care of people who have smoked heavily well into their eighties yet miraculously avoided the serious end consequences of nicotine addiction. Conversely, I have cared for health conscious macrobiotic or vegan food junkies who have died in their forties of breast cancer or leukemia.

Although this is just a giant crap shoot with extremely uncertain odds, the general rule of thumb for longevity is to not smoke, drink modestly or not at all, maintain normal body weight, exercise regularly and hope you got a bevy of good genes at the time of your conception. Then bank a little bit on good luck, too; because anyone crossing a street can still be hit by a bus.

It is axiomatic that we are born to die and that try as you may, you can never beat the grim reaper.

My Italian grandmother had a slightly different and more simplistic take on it all. She used to say:

  • La vita è un figlio di una cagna; e la vecchiaia è una carcassa morta in attesa di un Tesoro.

(Life is a son of a bitch; and old age is a dead carcass waiting for a scavenger.)

krebbs-cycle

 

The Krebs Oxidative Cycle. Not only your best friend; but also, your worst enemy

Krebs Cycle © Graphic; From Sequim Science
http://homepage.mac.com/dtrappeChem.f/lab.B10.html
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