Definition
of The Lymphatic System: The lymphatic system
in vertebrates is a network of conduits that carry a clear
fluid called lymph. It also includes the lymphoid tissue through
which the lymph travels. Lymphoid tissue is found in many
organs, particularly the lymph nodes, and in the lymphoid
follicles associated with the digestive system such as the
tonsils. The system also includes all the structures dedicated
to the circulation and production of lymphocytes, which includes
the spleen, thymus, bone marrow and the lymphoid tissue associated
with the digestive system.[1] The lymphatic system as we know
it today was first described independently by Olaus Rudbeck
and Thomas Bartholin.
The
dissolved constituents of the blood do not directly come
in contact with the cells and tissues in the body, but first
enter the interstitial fluid, and then the cells of the
body. Lymph is the fluid that is formed when interstitial
fluid enters the conduits of the lymphatic system. The lymph
is not pumped through the body like blood, but is moved
mostly by the contractions of skeletal muscles.
The
lymphatic system has three interrelated functions. It is
responsible for the removal of interstitial fluid from tissues.
It absorbs and transports fatty acids and fats as chyle
to the circulatory system. The last function of the lymphatic
system is the transport of antigen presenting cells (APCs),
such as dendritic cells, to the lymph nodes where an immune
response is stimulated.
The
study of lymphatic drainage of various organs is important
in diagnosis, prognosis, and treatment of cancer. The lymphatic
system, because of its physical proximity to many tissues
of the body, is responsible for carrying cancerous cells
between the various parts of the body in a process called
metastasis. The intervening lymph nodes can trap the cancer
cells. If they are not successful in destroying the cancer
cells the nodes may become sites of secondary tumors.
Diseases
and other problems of the lymphatic system can cause swelling
and other symptoms. Problems with the system can impair
the body's ability to fight infections.
- From WikiPedia