Acids and bases--MINI-TUTORIAL

The body is a marvelously adapted and regulated organism.

One of the manifestations of this is the balance demonstrated in its handling of acids and bases. 

Firstly, at its simplest, an acid is a molecule that donates protons (positively charged) or, more relevantly, receives (sucks up!) electrons (negatively charged). The degree to which a substance dissolves (or dissociates) in water to produce these hungry (needy?) protons is the STRENGTH of the acid. Sucking up electrons (or donating protons) to molecular substances leads to their breaking their chemical bonds. 

This is WHY (how) in the "macro" world acids dissolve things!

Bases are molecules that suck up protons, or "neutralize" acids. 

They keep acids from attacking and destroying molecules.

Strong bases, which produce molecules hungry for protons, can also break chemical bonds and cause "melting" of substances.

pH = negative log of the concentration of H+ (protons). 

The scale is 1-14, with 1 being strongly acidic and 14 strongly basic (remember it is a NEGATIVE logarithm).  Neutral = 7, where the concentration of H+ and the base (negatively charged) is equal. A solution that is acidly neutral is also electrically neutral. Remember that acids, since they are hungry for electrons, conduct electricity (which is flowing electrons). COOL, and LOGICAL.

The body produces a LOT of acids, which are as potentially damaging to its molecules (and therefore cells and tissues) as it is to other substances. Therefore the body has, of course, evolved a super-effective buffering (neutralizing) system that relies primarily on the kidneys. 

Another reason to take good care of those beans!

Mystery?

When "most people"--including clinicians--think of brain and nervous tissue they think first of neurons. These are the big bosses, of course, and have the real mysteries within them. They are also essentially eternal, not reproducing and therefore maintaining continuity, but once gone are (as of today) gone forever.

But "the other nervous tissue", neuroglia, consisting of several types of supporting cells (micoglia, astrocytes, oligodendrocytes, ependymal cells, Schwann cells) is as critical to nervous system functioning as neurons. These cells feed, protect, insulate, and generally allow the neurons to do what they do--"think" and send orders (signals) to all other cells of the body. The "blood brain barrier", which is a function rather than an organ, is a neuroglial function. The special immune properties of the central nervous system (CNS) are mediated by microglia. 

Recent research has also suggested that it is these cells that are responsible for forging connections between neurons, and therefore are responsible for learning and adaptation and even evolution. They have one very serious "weakness", however, and that is that they divide rapidly and often, setting themselves up to be the target of genetic decay. Over 98% of malignant brain tumors are neuroglial in origin, and they are also involved in many neurologic disorders, including multiple sclerosis, Alzheimer's, and several other neurodegenerative diseases.

The brain--both types of cells--takes 20% of our oxygen and at least 15% of our glucose even though it is no more than 2% of our body weight. It is the first organ to develop and the last to die. In between it is a miracle of sublime and elegant power and complexity.

Precision!

The kidney is, gram for gram, the most elegantly and effectively evolved organ in the body after the brain. The basic unit of function--the nephron, composed of glomerulus, tubules, mesangium, and the craftily-named juxtaglomerular appartus--is the most precise "filtering" system ever known. It controls fluids and electrolytes, and has a major role in all other functions of the body--blood, bones, GI system, reproduction, on and on. The only thing it doesn't do is "think"--a number of its mechanisms come close, though!

It is no wonder that chronic renal failure is the most devastating of diseases. Anyone familiar with the life of the dialysis patient knows how miserable it truly is to not have kidney function. Kidney transplantation is an option with better outcomes that dialysis, but it is still not a "cure" and most people who need such a transplant cannot get one.  

The truly unfortunate fact is that chronic renal failure (CRF), also know as chronic kidney disease (CKD) or the uremic syndrome (uremia), is on the increase, especially in the developing world and in the West where longevity is increasing. This is truly unfortunate since in most cases early diagnosis and treatment of the major risk factors--diabetes and hypertension--can prevent it. Make sure you and your loved ones get regular risk assessments and if a disease that effects the kidneys is present get it treated! NOW!

Power!

The liver

Beauty

Neurons!

Efficiency...

...one of thy synonyms is "pancreas".

Involved with BOTH digestion and anabolism, as well as making cuboidal epithelium into a number of wondrous subspecies, the pancreas is a marvel of evolutionary skill. 

Take care of yours today--lay off the booze!

Strength

The human body has evolved

a control and movement system

that allows us to do a broader range of things better than any

other mammal.

From running to painting,

singing to sleeping, we are superbly adapted to a complex and changing environment. 

Ultimately, this all-around strength is NOT due to big or powerful muscles but to the most

awesome "engine" known--the human brain and nervous system.

Food!

This is the "new food pyramid". The best nutritional advice is NOT on the web or on TV or in the grocery-store checkout lane--it is here.

The major problem with the nutritional state of Americans, contrary to the latest foodie propaganda, is not gluten or antioxidants or vitamins--it is CALORIES.

Specifically, too many! By 2020 40% of the adult U.S. population will be obese (BMI > 30).

There is no magic except this, and I give it for free: 

eat less, exercise more. If you take in more calories than you expend--FOR WHATEVER REASON--you will gain weight. If you expend more calories than you consume, you will lose weight. 

And sorry, Dr. Oz (who is not trained in nutrition, btw)--there are NO "fat burning foods".  The only thing that "burns fat" is energy consumption, which is done by our cells, not our foods, and only after all available glucose has been used. Glucose metabolism cannot be "bypassed" and all the other "eat more and STILL lose weight" diets are simply lies.

And carbohydrates are not poison!

Science is a method, not a philosophy

Association does NOT equal causation!

Back to class!

Welcome back to my Chamberlain students! I am so glad to see you!

During this session we will be studying muscles and nerves in A&P II, and the GI, renal, and reproductive systems in A&P IV. My blog postings will address topics relevant to these areas. Feel free to comment!

A general update to the blog's contents will also be undertaken.