Job, in his misery at the trials and temptations
from Satan and from his distress caused by his wife and so-called
friends, responded as all humans do in these conditions: he shed
tears. Little could Job know the complexity of such a seemingly
insignificant drop of water. Only in a modern scientific lab can
the true nature of a tear be discovered. Let us take just a few
minutes to look at the amazing structures that produce tears and
at the discoveries being made about tears even today.
Tears generally are classified into three types.
They are basal tears that are considered the normal moisture for
eye protection, reflex tears that are produced when a foreign
substance gets onto the eye surface, and physic tears that are
the emotional tears when we laugh or cry.
Tears are produced by almond-sized glands called
the lacrimal glands which are located at the top of the eye. They
drain out onto the surface of the eye through special excretory
lacrimal ducts of which there are 6 to 12 in each eye. As tears
are produced, the ducts drain them onto a special layer on the
eye called the tear film. This three-layered structure sits on
top of the cornea, which is the outermost layer of the eye. The
tear film layers are designed to prevent evaporation of the tears
while holding the lubricating tear on the eye and aiding in the
prevention of bacterial infection on the eye. After the tear is
moved over the eye by the eyelids, excess fluids are channeled
into the lacrimal canals and from there into the nasolacrimal
ducts which lead into the nose. If enough tears are present, our
noses will start to "run" as the tears are drained away.
A tear has been known for years to be a watery
solution which contains several salts (that is why tears taste
"salty"), mucus, white blood cells, lysozyme (a bacteria
fighting enzyme), and, most recently, a new class of fats, but
more on that a little later. The tears we produce keep our tear
film and cornea healthy as they keep these living cells of the
cornea from drying out. They make a slightly acid condition that
prevents bacterial growth, and then, when bacteria do make it
onto the eye, they will kill the bacteria by white blood cells
and enzymes. Tears are also known to aid in our ability to see
as they make a perfectly smooth surface on the cornea that is
necessary for light to pass through correctly so we can see without
interference.
For many years, little was known about the structure
of a tear. Research last year on tears revealed that a tear is
made of three layers of materials. The first is a coating of oil;
the second is a layer of water; and, inside, making most of the
tear, is mucus. The water and mucus, which comprise most of the
contents of a tear, were expected, but the discovery of oil was
full of surprises. Recently, these oils in tears were found to
be a previously unknown class of lipids called fatty acid amides.
This class of lipids was unknown until research was done on the
tear. Along with this new fatty acid material, a lipid known as
oleamide, which, before its discovery in tears, was only found
in the brain and central nervous system, was discovered. Both
of these discoveries surprised the researchers. Further investigation
showed that the lipids are responsible for "locking"
the moisture of the water and mucus onto the surface of the tear
film and cornea. In the brain, the oleamide is known to aid in
communication between brain cells. There is speculation that there
may be some communication between the cells of the eye surface,
but more study will be needed to confirm this.
So, in our tears of joy and sorrow, God has buried
mysteries that modern science is still trying to uncover. Let
us always marvel at the wisdom of the all-knowing God, for we
are truly "fearfully and wonderfully made." -Rt. 1 Box
116A, Belington, WV 26250. aedeverson@yahoo.com