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Our lymphatic system is vital to our survival. Our lymphatic
system plays a major role in our
body. Our lymphatics help with balancing the interstitial
fluid, transporting waste, distributing
immune cells, filtering foreign material and absorbing
nutrients especially from our GI tract.
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Lymphoid tissue starts at 5 weeks of fetal age. At birth,
lymphoid tissue is still immature
And about the age of 15 to 16 that lymphoid tissue reaches
adult levels. Primary lymphoid tissue could
be found in the thymus and also in the bone marrow. We have
secondary lymphoid tissue that
could be found in the tonsils, the spleen, our GI tract, our
appendix and our lymph nodes. Our
lymph nodes is a system of nodes that are connected by the
lymphatic ducts and the lymphatic
system and these lymph nodes interact to help filter our
blood and protect against foreign
material and also cancer cells. They are superficial and
deep nodes and this collection of cells
work in a network with the connective tissue. Our lymph
flows through lymph channels. These
channels start in the soft tissue as closed endothelial line
capillaries. They are single layer
squamous cells and they are supported by anchoring filaments
into the interstitial matrix. This is
important to consider because it is these anchoring
filaments connect into the cells that help
to hold open the gaps between individual cells to allow for
lymph to come in and for lymph
formation. These small tubes join to form larger lymph
channels. In the larger vessels, these
have more of a traditional intima-media and valves. There is
some smooth muscle control that
helps to propel the lymphatics and that is innervated by the
sympathetic nervous system then
these larger vessels communicate with the circulatory system
through nodes and through
lymph ducts. Lymph vessels could be found almost through all
tissues of the body. The
exceptions include the epidermis including the hair and
nails, the bone marrow, the endomysium
of muscles and cartilage and portions of the peripheral
nerves. It was once thought that there
were no lymph vessels in the CNS and brain, but the
lymphatic system was recently found to
run along the venous sinuses. Drainage of the lymphatic
channels of the abdomen, pelvis and
lower limbs all drain into the cisterna chyli. The cisterna
chyli is a dilation of the thoracic duct
to the right side of L1/L2 and it lies right behind the
right crus of the diaphragm next to the
abdominal aorta. This is important because that dilation
actually helps to get pumped whenever
we breathe and pulsations of the aorta help to propel fluid
through the thoracic duct at that
dilation. It is really important to understand how
lymphatics drain throughout the body and run
especially when we are trying to address any somatic
dysfunctions that may impede lymphatic
flow. Most of the body drains through the left thoracic
duct. The left side of the head and neck,
the left arm and thorax, the left and right portions of the
lower bodies of both lower extremities,
the thoracic and abdominal viscera all drain into that
thoracic duct. The right side gets the
right side of the head and neck, the right side of the chest
including parts of the heart and lung
on the right. Understanding what regions and organs drain to
the right and left side of the
body is important because you will then address key
structural issues based on what area you
are trying to promote lymphatic drainage. The right
lymphatic duct will drain into the right
subclavian vein whereas the thoracic duct usually will drain
into the left subclavian vein, but
first it pierces the fascia covering the thoracic outlet so
it is important to address any sort of
somatic dysfunction or restrictions in that region to allow
for proper flow. So, let us take a
closer look at the formation of lymph. Interstitial fluid is
an ultrafiltrate of blood. The production
of interstitial fluid is the filtration out of the
capillaries versus reabsorption. Lymph vessels
could collect interstitial fluid and it's about 2 to 3
liters per day. About 100 grams per day of
protein could escape from blood capillaries and then the
interstitial fluid also receives metabolic
waste. So, taking a look at pressures that drive fluid out
of the arterial and include hydrostatic
pressure and then on the venous end, plasma and colloidal
osmotic pressure helps to draw fluid
back in and in between there is an exchange of fluid between
the interstitial fluid and the
lymph and our circulatory system. So interstitial fluid
itself could be intracellular and extracellular.
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Intracellular fluid is about 40% of the weight,
extracellular is about 20% with interstitial lymph
actually being 15% and plasma itself being about 5%. There
are a lot of factors that affect the
flow of lymphatics. It is important to understand these
factors to better understand how to
address lymphatic issues and problems. So any sort of
increase in the interstitial fluid pressure
will increase the absorption of lymph into lymph capillaries
up to a certain pressure. So normally
interstitial fluid has a normal resting negative pressure of
-6.3. Now, as I slowly rise it so if I
start to get a little bit of swelling and it becomes more
positive it would open up the small
capillary filaments to increase the amount of lymph flow
into the lymphatic system. So once I
reached pretty much a pressure of zero, lymphatic flow could
be increased up to 20 times but
once I increased the interstitial fluid pressure greater
than zero what happens is it now
collapses those channels and prevents any sort of flow into
the lymph channels. So again,
interstitial fluid normally is negative and as it slowly
gets towards positive it will increase the
amount of fluid being absorbed into the lymph channels but
once the pressure goes above zero
meaning the pressure becomes positive those channels
collapse and it does not allow for any
sort of lymph to get into the lymph channels. The actual
flow of lymph could be influenced by
many different things. Intrinsically, the lymph vessels
itself will contract when dilated so if there
is distention of the lymph fibers it is going to cause it to
contract. The smooth muscle and the
lymphatic channels itself could also cause contraction and
propel lymph through the lymph
vessels. The lymphatic channels thta are in our lymphatic
system does not have a specific pump like our
circulatory system has the heart to pump fluid throughout
the system. Instead, our lymphatic
system really depends a lot on extrinsic factors to get
lymphatics to move and so the extrinsic
factors that affect lymph flow include the diaphragm. So
whenever the diaphragm moves we
talked about the placement of the cisterna chyli which is
the dilation along the thoracic duct
collecting all the lymph from our GI tract, our internal
organs, our legs so whenever the
diaphragm moves with inhalation-exhalation they will
actually physically help to pump the
cisterna chyli because the cisterna chyli lies right
posterior to that right crus of the diaphragm.
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Whenever we take a deep breathe in that creates a negative
pressure in the chest and abdomen
and then when we exhale it becomes a positive pressure. So
whenever we breathe, the motion
the diaphragm helps to contribute to pressure changes in the
thoracic cage. That pressure
change actually helps to draw lymphatics into the thoracic
cage. So when I inhale and take a
deep breath in and create a negative pressure more
lymphatics is drawn into thoracic cage
and when I exhale that change in pressure helps to propel it
along. So when you think about it,
we breathe about 12 breaths a minute that is almost 17,000
pressure changes a day whenever
we are breathing. Abdominal peristalsis also helps to move
along lymph so whenever our
abdomen contracts that is going to help move lymphatics. Our
lymphatic vessels tend to run
within the fascia surrounding muscle so every time we
contract our muscles that also helps to
propel lymphatics. It has actually been studied vigorous
exercise could actually increase
lymphatic flow 15 to 20 times compared to normal resting
flow. Our lymphatic vessels typically
run side by side to arteries. This is to help with improving
flow due to the pulsations of the
arteries. So when the arteries pulse, that motion and
movement also helps to affect the flow of
lymphatics.