- HIV/AIDS
- INFECTION with human T-lymphocytic virus 1
(HTLV-1), EPSTEIN-BARR VIRUS, or human her-
pesvirus 8 (HHV-8) - infection with HELICOBACTER PYLORI, the BACTERIA
believed responsible for STOMACH CANCER - occupational exposure to benzene
- occupational exposure to agricultural pesticides
and herbicides, notably organophosphates and
chlorophenols - first-degree relatives (parents, siblings, chil-
dren) who have lymphoma - chromosomal TRANSLOCATIONand other abnor-
malities
However, researchers do not know the extent
to which these factors influence the development
of lymphoma. Many people who develop lym-
phoma have no history of exposure to these fac-
tors, and far more people than not who have
exposure do not develop lymphoma. Reducing or
eliminating exposure to environmental toxins,
treating infections such as H. pylori, and maintain-
ing nutritious EATING HABITS can improve health
overall. Otherwise, there are no known measures
to prevent lymphoma.
See also AMYLOIDOSIS; B-CELL LYMPHOCYTE; CANCER
RISK FACTORS; CANCER TREATMENT OPTIONS AND DECI-
SIONS; ENVIRONMENTAL HAZARD EXPOSURE; ERYTHROPOI-
ETIN(EPO); LEUKEMIA; LIFESTYLE AND HEALTH; MULTIPLE
MYELOMA; NATURAL KILLER(NK) CELL; SIGNS AND SYMP-
TOMS OF CANCER; SMOKING AND HEALTH; STAGING AND
CRADING OF CANCER.
lymph vessels An extensive network of channels
that collect and circulate LY M P H, a watery fluid con-
taining immune cells and substances as well as
pathogens cleansed from the BLOODand tissues. The
lymph vessels, also called lymphatics, are similar in
structure to the capillaries and veins of the cardio-
vascular system but have thinner walls. The lymph
vessels carry lymph from the tissues through the
lymph nodes, where lymphocytes neutralize or kill
and macrophages consume pathogens, then deliver
the cleansed fluid to the blood.
The smallest of the lymph vessels are the lym-
phatic capillaries, which arise from cul-de-sac
structures within the interstitial fluid (fluid
between the cells) in the tissues surrounding the
CAPILLARY BEDSof the cardiovascular system. The
shingled, single-cell walls of the lymphatic capil-
laries are permeable, allowing fluid to seep inside
though preventing it from seeping back out. The
lymphatic capillaries merge into the afferent lym-
phatics, somewhat larger lymph vessels that carry
the lymph among the lymph nodes. The lym-
phatic capillaries in the SMALL INTESTINE, called
lacteals, are uniquely able to absorb the fatty
products of digestion, which they ultimately
deliver to the blood.
The larger lymph vessels are not permeable and
contain valves to keep lymph moving in only one
direction, toward the central body. Their pathways
roughly parallel those of the cardiovascular circu-
latory structures. In the central trunk region the
lymph vessels merge into three reservoir-like
structures. These structures are the- CISTERNA CHYLI, which collects lymph from the
lacteals and the abdominal lymph vessels - THORACIC DUCT, which collects lymph from the
cisterna chyli and the upper left body - RIGHT LYMPHATIC DUCT, which collects lymph from
the upper right body and head
The thoracic duct parallels the AORTAand drains
into the left subclavian vein. The right lymphatic
duct drains into the right subclavian vein. The
lymph then becomes part of the blood.
For further discussion of lymph vessels within
the context of blood and lymph structure and
function please see the overview section “The
Blood and Lymph.”
See also LYMPHADENITIS; LYMPHEDEMA; LYMPH NODE;
SENTINEL LYMPH NODE DISSECTION.lymph vessels 155