What is the
Lymphatic System?
Click to enlarge
Also
see Cancer.gov
"Shotty
lymph nodes" refers to clusters of small swollen
nodes. Shotty nodes may occur when the immune system is reacting to an
infection -- it doesn't necessarily point toward any particular
disease.
"Bulky
disease" generally describes a lymph node or
extranodal tumor that measures greater than ten centimeters in any
dimension.
calcified nodes are not really rare, and typically are the result of some past, healed infection. TB is well-known to cause them,
for example. Cancer is not."
medhelp.orgs
Cervical lymph
nodes are lymph nodes
located in and around the neck. See Image
mage on WebMD Anatomy
Anatomical Regions for the Staging of Hodgkin Lymphoma
SEER
click to enlarge
Lymphatics -
comprehensive list (alphabetical)
http://bit.ly/lymph-alpha
Lymph
nodes in head and neck
1: Submental
2: Submandibular
3: Supraclavicular
4: Retropharyngeal
5: Buccal
6: Superficial cervical
7: Jugular
8: Parotid
9: Retroauricular & occipital
Wikipedia
Also see:
catalog.nucleusinc.com
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Understanding the
lymphatic system
The lymphatic system
consists of organs, ducts, and nodes. It transports a watery clear
fluid called lymph.
This fluid distributes immune cells and
other factors throughout the body. It also interacts with the blood
circulatory system to drain fluid from cells and tissues.
The lymphatic system contains immune cells called
lymphocytes, which protect the body against antigens (viruses,
bacteria, etc.) that invade the body. See more on
lymphocytes below. It is abnormal cells of this type that cause
lymphoma.
Main functions
of the lymphatic system
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"to collect and return interstitial fluid, including plasma protein to the blood,
and thus help maintain fluid balance, |
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to defend the body against disease by producing lymphocytes, |
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to absorb lipids from the intestine and transport them to the blood."
Source
jdaross.mcmail.net |
Also
see from this source
Anatomy of lymph
system
Role of the lymphatic system in fat absorption and transport
The lymphatic
circulation as a drainage system (illustrated)
Lymph organs
Include the bone marrow,
lymph nodes, spleen, and thymus. Precursor cells in the bone marrow
produce lymphocytes. B-lymphocytes (B-cells) mature in the bone
marrow. T-lymphocytes (T-cells) mature in the thymus gland.
Besides providing a home for lymphocytes (B-cells and
T-cells), the ducts of the lymphatic system provide
transportation for proteins, fats, and other substances in a medium
called lymph.
Lymph nodes:
"Human lymph nodes are bean-shaped and range in size from a
few millimeters to about 1-2 cm in their normal state.
They may become enlarged due to a tumor or infection. White
blood cells are located within honeycomb structures of the lymph
nodes. Lymph nodes are enlarged when the body is infected due to
enhanced production of some cells and division of activated T and B
cells.
In some cases they may feel enlarged due to past infections;
although one may be healthy, one may still feel them residually
enlarged." Wikipedia.org
Lymph
"Means clear water and it is basically the fluid and protein that has
been squeezed out of the blood (i.e. blood plasma). The lymph is
drained from the tissue in microscopic blind-ended vessels called
lymph capillaries.
These lymph capillaries are very permeable, and because they are not
pressurized the lymph fluid can drain easily from the tissue into the lymph capillaries.
As with the blood network the lymph vessels form a network throughout the body, unlike the blood the lymph system is a one-way street draining lymph from the tissue and returning it to the blood."
Source
bbc.co.uk
"Unlike the cardiovascular system, the
lymphatic system is
not closed and has no central pump."
wikipedia.org "Lymph movement occurs despite low pressure
due to
peristalsis - smooth muscle and skeletal activity (everyday
activity and motion of the body).
"Secondary
lymphatic tissues control the quality of immune responses.
Differences among the various lymphatic tissues significantly affect
the form of immunity and relate to how antigens (bacteria, virus,
fungus, etc.) are acquired by these organs.
- Lymph nodes
are filters of lymph
- the spleen
is a filter of blood
- mucosal associated lymphatic tissues
acquire antigens by transcytosis to lymphoid tissue from the
"external" environment across specialized
follicle-associated epithelial cells." Source geocities.com
"Lymphatics
are found in every part of the body except the central nervous system.
The major parts of the system are the bone marrow, spleen, thymus gland,
lymph nodes, and the tonsils. Other organs, including the heart, lungs,
intestines, liver, and skin also contain lymphatic tissue."
gorhams.dk
Lymphoma
Is a disease in which
malignant lymphocytes grow too fast or live too long. These cells may
then accumulate in the lymph nodes or other areas of the lymphatic
system to form tumors. When these cells accumulate in lymph
nodes it's often called adenopathy
- the enlargement of the lymph nodes; but adenopathy can have other
causes.
There are many
benign reasons for enlarged lymph
nodes:
Diagnostic
Problems in the Evaluation of Lymphadenopathy, Weinstock, Straus
Cancernetwork.com
Lymphadenopathy:
Differential Diagnosis and Evaluation, Robert Ferrer, M.D., M.P.H.
American
Family Physician
Normal sized lymph nodes?
Human lymph nodes are bean-shaped. These
organs of the immune system can range in size from a few millimeters
to about 1–2 cm in their normal state. They may become enlarged due
to a tumor or infection, or lymphoma.
Warwick, Roger; Peter L. Williams (1973) [1858]. "Angiology (Chapter
6)". Gray's anatomy.
Reactive Lymph nodes
"LYMPH nodes are a combination
of burglar alarm and West Point. Like a burglar alarm they are on
guard against intrusive antigen. Like West Point, the nodes are in the
business of training a militant elite:"
pleiad.umdnj.edu
What's the deal with Waxing, Waning, and
Persistently Enlarged Lymph Nodes?
Lymph nodes can increase or decrease in
size for many reasons, including response to treatment, progression of
lymphoma, spontaneous regression of lymphoma, immune activation
against lymphoma, infection or the resolving of infection (reactive,
see above), and so on.
Therefore, imaging of
lymphoma is only an estimate of treatment response and disease direction.
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Collapsing
of necrotic
areas in lymph nodes may explain a sudden decrease in a
large lymph node.
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Residual lymphoid masses?
Following
treatment "a
residual mass persisting on CT after treatment poses a common clinical dilemma: it may indicate the presence of viable lymphoma, which requires further treatment, or it can be benign, consisting of only
fibrotic and necrotic tissues." PMID:
12644887
For this reason PET or Gallium scans may be used after treatment to help differentiate active disease from scar tissue.
Lymphoid tumors are made up of the accumulated abnormal
lymphocytes but also supportive tissue of different cell types:
“epithelial cells and also there is supporting tissue, called
connective tissue which is there to support the epithelial
cells”. These cells are sometimes referred to in shorthand
as tumor “stromal” cells.
Our understanding is that the macrophages (immune cells) will
eventually gobble up this necrotic material after successful
therapy, which explains why the treated “tumor” continues to
shrink well after therapy is done.
NOTE: The delayed shrinking of lymphoid tumor can lead to
questionable conclusions of the causal effect of subsequent
therapy – standard, investigational, and alternative, because
the tumor in some cases would have resolved with more time.
PET scans are used to help distinguish between necrotic and
viable tumor following treatment, but this test is not perfect …
can produce false positives due to inflammation.
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Reactive
lymph nodes
- Lymph nodes may enlarge when immune cells react to pathogen such
as virus or bacteria. Swollen glands, common to many
illnesses is an example of nodes enlarging in response to a
pathogen. This might also be called a flare. |
Resources
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Lymphedema PAL
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Quiz:
Quiz: Know your nodes:
knowyournodes.org
Leukemia and Blood foundation: Now is the time to get to
‘know your nodes’, and find out just how important your
lymphatic system is.
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Table of Lymphatic vessels
(comprehensive)
anatomy.uams.edu
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Spontaneous regressions
PAL
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Imaging residual masses: Gallium-67 scintigraphy:
a cornerstone in functional imaging of lymphoma.
Eur J Nucl Med
Mol Imaging. 2003 Jun;30 Suppl 1:S65-81. Epub 2003 Mar 18.
Review
PMID:
12644887 |
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Lymphocytes
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Lymphocytes,
also called
white blood cells, are described below. These
are small cells, 7-9 µm in diameter in blood smears ...
These cells are the second most common white blood cell
type, comprising about 30 % of the leukocyte population in peripheral
blood....
Lymphocytes travel in the blood, but they routinely leave capillaries
and wander through connective tissue. Therefore, lymphocytes may
be normally encountered at any time in any location. They even enter
epithelial tissue, crawling between the epithelial cells. They reenter
circulation via lymphatic system channels (hence their name)."
Source: Blood Cells www.siumed.edu
Life cycle of lymphocytes
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Develop in the thymus gland or bone marrow.
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B-cells grow (differentiate) and mature in the
bone marrow.
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T-cells also start out in the bone marrow. They
differentiate and mature in the thymus gland (beneath breastbone).
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B-cell and T-cell lymphocytes are distributed
through the blood stream, which eventually branches into tiny
blood vessels called capillaries.
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Some lymphocytes migrate to capillaries into
surrounding tissues. Some enter lymphatic vessels-tiny,
blind-ended tubes-and lead to larger lymphatic ducts and branches.
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Along the way, the fluid passes through lymph
nodes, oval structures composed of lymph vessels, connective
tissue, and white blood cells. Here, the lymphocytes either are
filtered out or are added to the contents of the node.
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![[Illustration]](http://www.merck.com/mrkshared/mmanual_home/illus/i161_1.gif)
