God’s Gift of Balance
“IT’S just sea legs,” my friends told me, “and it can last several days.” It was October 1990, and I had just stepped off a cruise ship onto dry ground after a seven-day trip on the Caribbean. What I thought was going to be a few days’ experience, however, has lasted for many months. It was as if I never got off that ship. Something went wrong with my vestibular system, the intricate balance system of the inner ear with its central connections in the brain.
What Is It? How Does It Work?
The coordinating center for your balance is found at the base of your brain called the brain stem. When you are healthy, you keep your balance because innumerable impulses are received from your eyes, your muscles, and your vestibular system.
Your eyes provide the brain stem with continuous sensory input about your external surroundings. Sensory receptors in your muscles, called proprioceptors, funnel information to your brain about the type of surface you are walking on or touching. But it’s your vestibular system that acts as an internal guidance system that tells your brain where your body is in space relative to the earth and its force of gravity.
The vestibular system is made up of five parts that deal with balance: three semicircular canals and two sacs. The semicircular canals are named the superior canal, the horizontal (lateral) canal, and the inferior (posterior) canal. The two sacs are called the utricle and the saccule.
The semicircular canals lie in planes at right angles to each other, like the walls and floor meeting at the corner of a room. The canals are passageways making up a labyrinth hidden in the hard bone of the skull called the temporal bone. Inside this bony maze is another labyrinth, called the membranous labyrinth. At the end of each membranous semicircular duct, there is what would look like a bulge, which is called the ampulla. On the inside of the membranous labyrinth is a special fluid called endolymph. And on the outside of the membrane, there is another fluid of yet a different chemical composition, called perilymph.
This swollen portion of the duct called the ampulla contains special hair cells in the form of bundles that are embedded into a gelatinous mass called the cupula. When you move your head in any direction, the endolymphatic fluid lags somewhat behind the movement of the canals themselves; and therefore the fluid bends the cupula and the hair bundles that it contains. The movement of the hair bundles causes changes in the electrical properties of the hair cell, and this in turn conveys messages to your brain via nerve cells. Messages travel not only from these individual hair cells to the brain down what are called afferent nerves but also back from the brain to each hair cell through efferent nerves to give the hair cell compensating information when this is necessary.
The semicircular canals detect angular or rotational movement of your head in any direction, such as tilting it forward or backward, laying it to one side or the other, or rotating it to the left or the right.
The utricle and the saccule, on the other hand, detect linear acceleration; they are therefore called the gravity sensors. They too contain hair cells in what is called the macula. The saccule would, for instance, send information to your brain that would give you the sensation of accelerating upward when you rise in an elevator. The utricle is the main detector that responds when you’re riding in a car and suddenly accelerate. It sends information to your brain to give you the sensation of being thrust forward or backward. Your brain then combines this information with other impulses to make decisions, such as how to move your eyes and limbs to respond to your apparent motion. It helps you to keep your orientation.
It’s a marvelous system that honors its Designer, Jehovah God. Even research scientists cannot help but be impressed by its design. A. J. Hudspeth, professor of biology and physiology, wrote in the magazine Scientific American: “Further work, however, can only reinforce a sense of wonder at the sensitivity and complexity of this miniaturized piece of biological apparatus.”
Malfunctions of the Vestibular System
In my case my inner-ear problem was diagnosed as otospongiosis or otosclerosis. This is a condition where the bone in which one’s vestibular system resides becomes soft or spongy. Normally this bone stays very hard, even harder than the bone material of the rest of your body. In the process of softening, it is thought, an enzyme is produced that seeps into the fluid of the inner ear and disrupts it chemically or in effect poisons the fluid. This can cause the bizarre sensation of constant movement even though you may be standing or lying still.
For me it made the pavement below my feet feel as though it were rippling in a wave motion sometimes as much as a foot [a third of a meter] high. When lying down, I felt as if I were lying in the bottom of a rowboat in the midst of three-foot-high ocean waves. The sensation did not come and go as in the case of some dizzy spells, but it came and stayed with me 24 hours a day for months on end. The only relief came when I was unconscious while sleeping.
Causes and Treatments
The cause of otospongiosis/otosclerosis is still unknown, although some connection with the hereditary factor may be involved. The condition has been hard for medical science to study because it seems to be unique to humans. Rarely, if ever, does it appear in animals. Otospongiosis can cause tinnitus (ringing in the ear), a feeling of fullness, light-headedness, an off-balance feeling, or various forms of vertigo (dizziness). The same condition can cause a fixation of the stapes in the middle ear and cause conductive hearing loss. If otospongiosis reaches the cochlea, it can also cause sensorineural hearing loss by destroying nerve function.
There are treatments for this condition. Some involve surgery (see Awake! of July 8, 1988, page 19); others attempt to arrest the bone deterioration through calcium and fluoride supplements. Sugar-free diets are sometimes suggested because the inner ear is extremely hungry for blood sugar. In fact, the inner ear requires three times as much sugar to energize it as an equivalent volume of the brain does. A healthy ear handles the normal fluctuations in blood sugar quite well; but once the ear is damaged, these fluctuations can cause you to spin. Caffeine and alcohol also seem to be detrimental once your inner ear is not functioning properly. Although the cruise ship ride, mentioned at the beginning of this article, didn’t really cause the problem, the changes in temperature, humidity, and eating habits likely triggered the disequilibrium.
Your inner ear does more than hear for you. In a marvelous and wonderful way, it helps you to keep your balance. Its design should make us marvel at the handiwork of our Maker, and it should deepen our appreciation for his Creatorship.—Contributed.
[Diagrams/Picture on page 26]
(For fully formatted text, see publication)
Your Amazing Vestibular System
Vertical motion detector
Organ of hearing
Horizontal motion detector
Measures angular movement