In This Issue

Nervous System, Part V

Weight Training Form Abuse

Multivitamin/mineral Update

Brain Function Update

Questions And Answers

BRAIN PROTECTION "STUFF"

Meninges

This protective mechanism consists of three membranes of connective tissue that: 1) cover and protect the CNS, 2) surround and protect the blood vessels supplying the CNS, and 3) contain CSF.

Just under the skull lies the dura mater, a tough, leathery, two-layer sheet of fibrous material. Appropriately, dura mater means "tough mother." The next layer, the arachnoid layer, is loosely connected to the third layer by web-like threads, allowing a "space" for major blood vessels and CSF circulation. This third layer, the pia mater, covers the brain tightly, dipping into all of the brains crevices, and it contains many fine blood vessels which transport blood from the larger vessels in the arachnoid layer deeper into the brain.

Cerebrospinal Fluid

This "liquid cushion" gives buoyancy to the CNS - our brains float, which keeps them from collapsing from their own weight. CFS cushions both the brain and spinal cord from blows or jolts. CFS also helps nourish the brain, and removes waste, as well. Only about a half-a-cup of CFS is available at any one time, but that seems to be enough.

CSF is manufactured in the brain from blood plasma, and then moves into the ventricles where it circulates into the spinal cord.

Blood-Brain Barrier

The function of the blood-brain barrier is to prevent some blood-borne critters from entering the brain tissue. Normally, capillaries allow nutrients, oxygen, and other molecules into brain tissue, but some toxins are blocked out by the blood-brain barrier to protect CNS neurons.

Brain capillaries are the least permeable in the body, but they do allow required nutrients to pass; but, in addition to oxygen, alcohol, nicotine, and anesthetics are also allowed in.

THE SPINAL CORD

The spinal cord starts at the bottom of the brain stem and runs down through the vertebral canal in the spinal column to the upper part of the lumbar spine - typically to the disc between L1 and L2 (see Note -1). It functions to: 1) innervate sensory and motor nerves below the head, 2) provide a two-way path for neural contact between the body and the brain, and 3) act as a major reflex center. Just like the brain, the spinal cord is protected by bone, meninges, and CSP.

The spinal cord does actually go lower than the upper lumbar vertebrae, but devoid of nerves. This extreme end is attached to the coccyx, and is merely an anchor.

There are 31 spinal nerves (which serve both the upper and lower body) that exit at four areas along the spinal column: the cervical nerves, thoracic spinal nerves, lumbar spinal nerves, and sacral spinal nerves.

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Note 1 - L1 and L2 are anatomical labels for the first and second vertebrae of the lumbar spine - lower back. But note that formal anatomy only presents an idealized model of the human body. Individual differences are widespread. Organs aren't always where they are "supposed to be," blood vessels branch or don't branch "by the book." I was once wearing an anatomical T-shirt (skeleton) in a store where a clerk was staring at it, and mentioned that she had an extra rib - unlike my shirt. When a doctor is opening up a body for surgery, all kinds of surprises might be found.

SPINAL CORD GRAY MATTER

The spinal cord contains the spinal nerves that innervate the neck, limbs, and trunk; and consists of an outer region of white matter, and an inner region of gray matter - a concoction of neuron bodies, short unmyelinated axons, and dendrites and neuroglia. A cross section looks more-or-less like an "H." The crossbar of the "H" contains the narrow "central canal," which is filled with CSF. The "uprights" contain interneurons that collect information from sensory neurons whose cell bodies are outside of the spinal cord, and cell bodies of motor neurons, which send their axons out of the spinal cord to muscles and glands.

The spinal gray matter is further divided by innervation to either somatic or visceral body areas.

SPINAL CORD WHITE MATTER

Made-up of both myelinated and unmyelinated axons, these fibers allow communication between different parts of the spinal cord, and between the spinal cord and the brain. The fibers of the spinal cord accommodate transmission of sensory information from the sensory neurons to the brain; and motor instructions from the brain to the spinal cord.

SENSORY AND MOTOR PATHWAYS

"Pathways" are just the "roads" between the brain and the rest of the body. Some generalizations about these pathways are:

• Most of them cross over from one side of the CNS to the other.
• All pathways are paired - left and right sides of both the brain and spinal cord.

H ow about some form faults with weight trainers in gyms? Years of membership in one gym or another have reinforced the fact that form abuse is rampant, especially with males of all ages. Women are not always perfect, but they are usually close to it after someone shows them the proper form. Men are frequently, but not always, more inclined to pursue poor form, largely because they insist on using more weight than they can properly handle.

Here are some exercises which are frequently performed incorrectly.

• Crunches - A common error among both men and women is to rock the head back-and-forth. Slow down, keep a space between your chin and chest - pretend like you are holding a large orange there. Also, in the hands-behind-your-neck position, keep your elbows pointed out to the sides - that will help to keep you from pulling on your neck.

• Squats - Using a barbell often results in too much forward lean, which tends to cause both too much stress on the lower back, and a projection of the knees past the toes, which adds shearing force to the knees - and they don't like it. Keep your feet flat on the floor, don't lean forward more than 45°, keep looking forward, and the squat should be done from the heels.

• Lat Pull-downs - Here is another "man thing:" Grab ahold of the bar, then sit down hard and pull hard to get the bar moving - so, what is happening here is that momentum is being maximized instead of muscle power. But we aren't done - now "he" practically lets go of the bar so it rises mostly without resistance, and of course his butt comes up off of the bench in preparation for another jerk-it-down repetition. KEEP YOUR BUTT STUCK TO THE BENCH UNTIL YOUR SET IS FINISHED. And don't let the weights clang together; that can damage equipment, and it is another momentum starter. And I don't recommend behind-the-neck exercises, but for those who won't give them up, don't get into the head bobbing routine. Sit as close to the weight stack as you can, lean forward slightly, face forward; then pull the bar down while keeping your body stable, and raise the bar under control - head still not moving. Raise the bar to full extension; that is, full lat extension - elbows may be slightly bent.

• Upright (or Vertical) Row - Some people manage to make this exercise into a kind of convoluted reverse curl by pulling the bar up near the chin and then raising it a little higher by using hands and wrists. But this is a back, not arm, exercise. The upward pull should bring the bar up close along the body to just under the chin. With your hands about eight inches apart on the bar, imagine pulling up with your elbows - up and back. Your elbows should remain higher than the bar throughout the lift (although inflexible shoulders sometimes prevent a full range pull). Do the best you can, but the bar should never be out in front of your face.

• 1-Arm Row - The major abuse with this exercise is rolling one's back from side-to-side. The proper position is a flat back. And I prefer a slightly diagonal arm movement (like sawing a log), as opposed to straight up-and-down, where there is a tendency to "drop" the weight rather than lower it under control. The elbow should go as high above the plane of your back as you can get it without rotating your entire torso.

• Seated Row - For many people this is a big momentum exercise, not so much the back exercise that it's supposed to be. What you typically see is a guy who stretches forward to grab the low cable handle, then lurch back to an almost laying down position, and somewhere in this movement the handle is jerked back to the lower abdominal area. Then he sort of relaxes and lets the weight pull him back to the starting position. The way this exercise should go is to bend forward and grasp the handle (back is flat, not humped), then sit up in an erect position, then pull the handle back until it touches the lower abdomen, then slowly extend your elbows (As before, you want a full extension of your lats, but elbows should stay "soft.") while remaining in an erect position. Finish the set before stretching forward again.

• There are some people who claim that the forward stretch gives them some lower back work in addition to lats. And so it can, but only as a compound exercise: 1) stretch forward and grasp the handle, 2) sit up vertically and pause, 3) pull the handle to your mid-section, 4) extend elbows (soft, remember) and pause, 5) stretch forward to the starting position. That's one.

• Side Lateral Raise - It is common to see this exercise done with the forearm and wrist laterally rotated - thumbs higher than little fingers - which puts the stress on the anterior (front) aspect of the deltoid muscle rather than on the medial (middle) aspect, which is supposed to be the purpose of the exercise. To target the medial aspect, rotate your wrist so that the thumb is below the little finger.

• Arm curls - This one really gets abused. Have you seen this: he grabs a barbell, with arms extended, then bends forward at the waist, and bends his elbows a little, then bends his wrist to set himself up in a power position. He then stands up quickly and simultaneously throws the weight up toward his shoulders. At the point where momentum starts slowing down, he bends backward to finish the concentric half of the rep. Then he straightens up and bends forward as he more-or-less drops the weight to the starting position, and in the process completely bypasses the eccentric (or negative) half of the rep.

• Triceps Kickback - In the hands of some people, this exercise becomes little more than a shoulder swing. "She" grabs a dumbbell, bends forward ever so slightly, bends her elbow a bit; then from the shoulder, starts a rearward movement which includes straightening the elbow. Now the shoulder starts a forward swing and the elbow simultaneously bends a little, and the next rep follows. The shoulder should not move at all, and she should bend forward enough to hold the upper arm parallel to the floor, with the forearm vertical. The only thing that moves in this exercise is the forearm/hand. The shoulder and upper arm remain rigidly in-place, and should refrain from flying out to the side - straight back it goes, and the forearm should only go to the vertical position (a 45° range).

• Triceps pushdowns - Is this you: take ahold of the bar, and pull/push it down to your upper thigh area, then let the bar up again with your elbows partly bent and out in front of your trunk. Now you push the bar down largely using your shoulders, while you also straighten your slightly bent elbows. Note that this is a triceps exercise, not a shoulder or back exercise. To isolate the triceps as much as possible, your elbows should be tucked into your sides, and your upper arms should not move - only your forearms move, and the range-of-motion should be between midchest and upper thigh.

  Some people, when using a heavy weight, lean over the bar and push straight down so that their elbows have to bow outward. I don't like this form because it involves upper body weight in the push down, and because the range-of-motion is limited.

I t is becoming increasingly clear that a multivitamin/multi-mineral supplement may be necessary to insure that everyone gets enough folic acid, vitamin D, calcium, and vitamin E.

Some things you should know about vitamin supplements are that they won't fix a lousy diet. Eat healthy - there are important nutrients, like phytochemicals, that are found in fruits and vegetables, but are not included in pills. There are many health benefits in real food that haven't even been identified.

Also, don't assume that more is better. Sometimes more is toxic, so don't abuse vitamin intake.

Don't automatically go for the high-priced varieties. More exexpensive doesn't necessarily insure better quality. Wal-mart or K-mart store brands are among the higher quality multi's. Your multi should be something like Centrum or Theragran-M, plus about 500 mg of calcium.

So why folic acid? It is particularly important for pregnant women in the U.S. because it has been proven that folic acid can prevent neural tube birth defects like spina bifida. Consequently, it is recommended that all women of child-bearing age, and who can become pregnant, should take 400 mcg of folic acid daily. Even those for whom pregnancy isn't in the cards can benefit from folic acid because it seemingly reduces risk for a heart attack by lowering homocysteine levels in blood. [See the Feb '98 Newsletter.]

Okay, so what about vitamin B-12? It is important for older people because they often have atrophic gastritis, which prevents them from separating B-12 from food, and B-12 is required to convert folate to usable form. Folic acid is a more active form of folate, and is the ingredient used in pills.

Tufts University's Robert Russel recommends 25 mcg of B-12 for older adults. Centrum Silver and others specifically formulated for seniors contains 25 mcg, as opposed to 6 mcg in most multi's.

Now calcium - it is a very important nutrient. Everyone knows the bones and teeth routine, but it is also necessary for all muscle contractions, and some other functions. Because of its importance, a deficiency causes the body to go to the calcium bank - bones - and make a withdrawal. A 19-50 year old body needs 1000 mg daily, and a body over 50 needs 1200 mg.

Finally, vitamin D, which won't be belabored here because it has been the subject or recent Newsletters. Suffice it to say that without proper levels of D, calcium absorption is severely limited (about 15%), resulting in the aforementioned calcium bank robbery. Those aged 50 and under need 200 IU per day, and those 51-70 need 400 IU. Those over 71 need 600 IU. This is serious, bone fractures from inadequate calcium can be an elderly person's worst nightmare.

I t is an interesting case of "synchronicity" that during presentations of the geography and functions of the human brain, a new understanding of one of the brain's functions - language processing - has been achieved.

It has recently been reported in the news media that a San Jose woman (identified simply as "VJ") suffering from epilepsy finally opted for a procedure called "split brain surgery." For years she had serious seizures sometimes leading to serious accidents. She had exhausted conventional treatments, not to mention family financial resources, before trying this radical surgical option.

The results have been gratifying, but with one highly unexpected result: she can no longer write even though she can read.

Her new problem has put into disarray the previously held belief about the organization of the brain. Language functions in particular - reading, writing, speech - were thought to be located in one area of the brain. But the results of VJ's surgery, which was aimed at quieting her seizures by cutting the band of nerves that connect the right and left halves of the cerebral hemisphere; disproved that idea. VJ now has, effectively, two minds, at least as far as language processing goes. And there are other oddities: like her hands sometimes act in opposition; for example, one hand may want to open the refrigerator, while her other hand wants to close it, simultaneously. At other times both sides agree on an action, but they both try to do it, simultaneously. Another example - she can't do something as simple as make a grocery list because her left brain can determine that a butter dish is empty, but she can't write the word "butter" on a list because her right brain controls the motor ability to write the word. So she can't connect between recognizing the empty butter dish and writing it on a grocery list. The two functions are literally in two separate worlds.

(Q) Is there anything new on whether or not to take a vitamin E supplement?
H.M.W.F., Roseburg, OR

(A) The following answer isn't new, but is just another source suggesting possible benefits of taking vitamin E supplements. First a little background: Vitamin E is a powerful antioxidant, which is a substance that gives up an electron to a free-radical, which is an oxygen molecule with a missing electron. Free-radicals can steal electrons from vital cell structures, which damages cells and may lead to disease.

Now, some potential benefits of vitamin E:

• It may have a protective effect against cardiovascular disease.
• It may reduce the risk for some cancers.
• It may slow the progression of Alzheimer's Disease.
• It may enhance the immune function in the elderly.
• It may protect against Parkinson's Disease.

He says 400 IU is a satisfactory dose for heart patients, and that 400 IU is satisfactory for everyone else. Exceeding that level is not recommended. A recent study found that doses of 1000 IU actually had a prooxidant effect.

(Q) Some friends have been strongly suggesting that I give up eating beef - too much fat and cholesterol. Should I?
J.S., Tacoma, WA

(A) Not necessarily. Ignoring all but nutritional reasons for giving up beef, it can be a healthy choice, in moderation. Leaner cattle are being bred [Whatever happened to beefalo, anyway?], and the leanest cuts - top round, eye of round, round steak, sirloin, flank steak, tip roast, porterhouse, T-bone, and tenderloin can contain as little artery-clogging saturated fat as chicken or turkey. It also contains important B vitamins, including B-12 which is absent from plant sources, and lots of zinc and iron. But, it is important to limit servings to about three ounces (about the size of a deck of cards) a few times a week.

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Send questions or comments to Michael Fenner: e-mail to Mike Fenner
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