Page 61 - The Miracle of Electricity in the Body

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Synaptic
knob
Axon
Myelin
sheath

Cross-section of myelin
sheath surrounding the axon

Cell body

Nucleus
Node of
Ranvier

Dendrites

If There Were No Insulation in the Nerve Cells
Multiple sclerosis (MS) is a disease in which the faulty working of the immune system
damages the myelin sheath. As a result, the nerve cell membrane opens and sodium is
lost along the axon. As the disease progresses, the amount of myelin declines and the
speed at which impulses are transmitted falls to a few meters per second. Leakage
gradually becomes so acute that the axons, cell extensions, become unable to forward
messages, and the target muscle is paralyzed. Even this myelin sheath, a very small
detail in the body’s electrical system, is of enormous importance. Every one of these
details is an example of the superior nature of the creation of our Lord, the
Compassionate and Merciful.

leading to a loss of power. Were it not for the myelin, electrical signals
would leak into surrounding tissues and thus dilute the signal, and pos-
sibly harm the body. In addition, this insulating substance significantly
increases conductivity, allowing signals to move more quickly.
Small unmyelinated fibers conduct at speeds of only 1 to 2 meters
(3.3 to 6.5 feet) per second, while those covered in myelin can do so at
speeds of up to 100 meters (328 feet) per second. 36
The myelin-covered nerve fibers transmit signals from our sense or-
gans to the brain and from the brain and spinal column to voluntary
muscles. Actions under our control are so rapid, often so automatic, that