Courtesy: Medical Miracles, from Readers Digest 1981.
November.
From the frontiers of science and the far horizons of
personal courage, these stories of medical triumphs and miracles will reaffirm
your faith in the awesome powers of the human spirit. Dramatic victories and
human triumphs.
Selected and edited by the editors of Readers Digest.
“Our Amazing “White Bloodstream”: By J.D. RATCLIFF
It is one of the world’s rivers of mystery—sluggish, largely
unmapped, many miles long. A remote
Amazon tributary? No, the lymphatic
system of your body.
The lymphatic system has puzzled physiologists since early
Greek times. Only now is the ‘white
bloodstream’ beginning to yield up its secrets—thanks to new tools and
laboratory techniques. One thing becomes
increasingly clear: our healths, even our lives, depend on how well this
complex system functions.
In contrast to the bloodstreams, which follows a
swift-flowing closed circuit from arteries to capillaries to veins and then
back to arteries, the lymphatic system flows slowly in a single direction. Its initial rivulets—microscopic in
dimension—originates in intercellular spaces.
Fluid gathered here passes through ever-enlarging ducts until it reaches
the lower neck region, where it empties into veins leading to the heart.
Much of the mystery surrounding the lymphatic system traces
to the fact that most of its ducts are so fragile that they are invisible—the
smallest have walls of only one-cell thickness.
And the fluid they carry is ordinarily almost clear as water. Moreover, at the touch of a probe, all bug
the largest lymphatic vessels collapse, as they’d at death. Exploring such a gossamer stream has called
for supreme ingenuity which cast shadows on X-ray films, second, radioactive
isotopes, which leave a track of telltale radiation.
Explorations via these and other techniques reveal
fascinating insights into the ‘geography’ of the body. In many respects the body is like a vast
swamp. Its trillions of fluid bathed
cells live an aquatic life. The
lymphatic network, it can now be seen, provides an all-important drainage
system. To nourish cells, blood
capillaries constantly leak minerals, fats, vitamins and sugars, along with
fluids and blood proteins. Much excess
fluid, together with cellular wastes, passes back through capillary walls to be
carried away bye veins. But not
all. If the lymphatic system did not
carry a large portion of their remaining seepages back to the bloodstream, we
would all ‘bleed’ to death internally in a matter of hours.
Loss of blood proteins through capillary walls would be
particularly disastrous. Dr.
H.S.Mayerson, of Tulane Medical School, tagged blood proteins with radioactive
iodine, then measured the rate at which they passed into lymph vessels. Calculations indicated that half of our blood
protein is lost every 24 hours! But for
the prompt retrieval of the protein by the lymphatic system this constant loss
would spell catastrophe. The route of
return is reasonably well known. A
gathering system of minute lymph capillaries collects fluid—how, no one
knows—and passes it along until it finally reaches the right lymphatic duct or
the thoracic duct. The later is the
largest vessel in the lymphatic system; soda-straw-size, it passes some 16
inches upward through the center of the body, finally emptying into the
bloodstream.
What propels this great lymphatic system? Reptiles and fish have lymph
‘hearts’—pulsating tubes—to move fluid along.
Man does not. Apparently—this is
one of the lymphatic system’s mysteries—lymph is propelled mainly by muscular
contractions from breathing, walking, of internal pulsations. As muscles tighten, lymph vessels are
squeezed, and fluid is pushed along.
Backflow if prevented by flap valves located at regular intervals in the
larger lymphatic.
The lymphatic network has other jobs besides drainage and
maintenance of fluid balance. Spaced
along the channels are hundreds of nodes—bean-shaped masses of tissue that
range from pinhead size up to an inch long.
They serve as filters, removing dangerous impurities much as an oil
filter does in a car. These lymph nodes
are so numerous that, if one fails, another a few inches farther along is
likely to do the job. This filter system
traps almost anything that is potentially harmful—dead red-blood cells,
chemicals, even excess tattoo dye. Lymph
modes in the lung areas of city dwellers are often dark form soot filtered out
of murky city air.
Suppose you cut your finger or step on a nail. Inevitably, bacteria are carried into the
body. They could be lethal but for the
lymph nodes that strain them out, then destroy them. Generally, these filters are so efficient
that the lymph they finally deliver to the bloodstream is clean and safe.
Still, they can be overwhelmed. The most dramatic examples are offered by
that terror of a disease, bubonic plague.
Here the lymph nodes struggle valiantly to filter out and destroy the
invading organisms, but it is a losing battle.
On a less dramatic scale, we have all seen evidence of
lymph-node difficulties. It may seem
odd, for example that an infected finger causes pain and swelling in the
armpit; of that an infected toe similarly affects the groin. But concentrations of lymph nodes are located
in these areas, and discomfort there announces that a battle royal against
bacterial invaders is under way.
While lymphatic filtering action is one of the body’s greatest
protective mechanisms, it can also lead to trouble. Striving to trap anything that would be
harmful in the bloodstream, the lymph nodes trap cells shed by cancers. These cancer seeds often sprout and grow
there; indeed, this appears to be one of the chief routes of cancer
spread. This is why surgeons always pay
particular attention to the lymphatic system near a primary cancer. In breast removal, for example, the greatest
care is exercised to remove lymphatic and lymph nodes in all surroundings areas,
particularly the armpit.
Transport is one of the lymphatic system’s big jobs. Mounting evidence indicates that this is
probably the route by which some of the critically important hormones are
distributed through the body. Another of
the system’s intriguing activities is the handling of dietary fats. Proteins and carbohydrates are absorbed
directly into the bloodstream along the digestive tract. Most fats are not directly absorbed—and with
good reason: in heavy concentration, fats are injurious to red-blood
cells. The lymphatic system solves this
problem by absorbing fats from the intestine and dribbling them into the
bloodstream in amounts that can be safely handled.
The lymphatic system also produces antibodies, which destroy
invading bacteria, and it manufactures at least one fourth of the
infection-fighting white cells that circulate in the blood stream. Whenever infections develop, the lymphatic
system goes into frantic activity, producing white cells by the tens of
thousands and rushing them to the scene of trouble.
Usually, the lymphatic system performs so efficiently that
we are hardly aware of its existence.
Still, from time to time it does announce its presence. On long plane rides and in theaters, women
sometimes kick of their shoes. Reason:
when the feet are inactive, fluid stops flowing and collects; feet5 swell. During surgery, lymph channels are inevitably
severed, where upon fluid collects in intercellular spaces, swelling follows in
the surgical area and persists until new lymph channels sprout. Children after suffer from ‘swollen glands,’
particularly in the neck area. This
means that lymph nodes “glands” are inflamed.
At times, too, the system lacks the reserve capacity to
handle jobs thrust upon it. In the
lungs, for example, blood vessels may ooze fluid faster than the lymphatics can
carry it away. This can happen in
pneumonia, in certain type of heart disease or when irritating chemicals damage
lung tissue. Unless the lymphatic system
can meet the challenge, the victim may drown in his own juices.
The lymphatic system has its own special disease
problems. It is the chief target of
lymphatic leukemia, and of Hodgkin’s disease—a cancer like illness marked by
enlargement of nodes. Until lately,
medical texts said that the latter disease was always fatal. Recent advances offer some hope of changing
the picture, however. High-voltage
radiations appear to destroy the lymph system.
In one recently reported series of cases, where treatment was begun
early, two thirds of those treated in this manner were alive at the end of five
years—the usual yardstick of cancer cure.
Other studies suggest a link between lymphatic difficulties
and deposition of fat in artery walls—which can lead to blockage of heart
arteries and to death. Similarly, there
may be a link between lymphatic disorders and serious malfunction of the
kidney.
Thus, this great river of mystery may well hold the key to
dozens of disease riddles. As it is
given-increasing research attention, discoveries of vital importance to all of
us will inevitably be made along its banks.
