Lymphatic system
71425
225549575
2008-07-14T07:18:37Z
KC Panchal
3449833
/* Diseases of the lymphatic system */ reorganized the portion on lymphedema
{{Infobox Anatomy
|Name = Lymphatic System
|Image = Illu lymphatic system.jpg
|Caption = An image displaying the lymphatic system.
}}
The '''lymphatic system''' in [[vertebrate]]s is a network of conduits that carry a clear fluid called [[lymph]]. It also includes the lymphoid tissue that the lymph travels through. Lymphoid tissue is found in many [[Organ (anatomy)| organs]], particularly the [[lymph node]]s, 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 [[lymphocyte]]s, which includes the [[spleen]], [[thymus]], [[bone marrow]] and the lymphoid tissue associated with the [[digestive system]].<ref name=grays>{{cite book |last= Warwick|first= Roger|coauthors= Peter L. Williams|editor= |others= illustrated by Richard E. M. Moore|title= Gray's anatomy|origyear= 1858|accessdate= 2008-06-30|edition= Thirty-fifth Edition||year= 1973|publisher= Longman|location= London|pages= 588—785|chapter= Angiology (Chapter 6)}}</ref> The lymphatic system as we know it today, was first described independently by Rudbeck and Bartholin.<!--As of now, this stands unsubstantiated. I doubt if WBCs were known at that time. Leeuwenhoed did not create microscope before 1654.It was first described in [[1651]] as the source of white blood cells.<ref name=Thomson1843/>-->
The dissolved constituents of the [[blood]] do not directly come in contact with the [[cell (biology)|cells]] and [[tissue (biology)| 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, it is moved mostly by the contractions of [[skeletal muscle]]s.
The lymphatic system has three interrelated functions. It is responsible for the removal of <!--"excess"--this gives a wrong impression that the removal of interstitial fluid is an occasional event, which it is not. KC Panchal--> interstitial fluid from tissues. It absorbs and transports [[fatty acids]] and [[fat]]s as [[chyle]] to the circulatory system. The last function of the lymphatic system is the production of immune cells, such as [[lymphocyte]]s, including [[antibody]] producing [[plasma cell]]s and [[monocyte]]s.<ref>[http://www.lymphomation.org/lymphatic.htm Lymphatic system]</ref>
The study of lymphatic drainage of various organs is important in treatment and diagnosis 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 [[edema|swelling]] and other symptoms. Problems with the system can impair the body's ability to fight infections.
== Organization ==
<!--I'm still in the process of completing this section, so it must be looking awkward. Others are free to add content to it--[[User:KC Panchal]]-->
The lymphatic system can be broadly divided into the conducting system and the lymphoid tissue.
The conducting system carries the lymph and consists of tubular vessels that include the [[lymph capillaries]], the [[lymph vessel]]s and the [[Right lymph duct|right]] and the [[thoracic duct|thoracic]] ducts.
The lymphoid tissue is primarily involved in immune responses, and consists of [[lymphocyte]]s and other [[white blood cell]]s enmeshed in connective tissue through which the lymph passes. Regions of the lymphoid tissue that are densely packed with lymphocytes are known as ''lymphoid follicles''. Lymphoid tissue can either be structurally well organized as lymph nodes or may consist of loosely organized lymphoid follicles known as the [[mucosa-associated lymphoid tissue]].
==Formation of lymph==
[[Image:Illu capillary microcirculation.jpg|thumb|250 px|Formation of interstitial fluid from blood]]
[[Blood]] supplies nutrients, and important [[metabolite]]s to the tissues, and collects back the waste products that they produce, which requires exchange of respective constituents between the blood and tissues. However, this exchange is not direct, and is effected through an intermediary called ''interstitial fluid'' or ''tissue fluid'' that the blood forms. Interstitial fluid (ISF) is the fluid that occupies the spaces between the cells and acts as their immediate environment. The composition of ISF keeps on changing depending upon what substances are removed or added by blood and the cells in the vicinity. Water and [[solute]]s can freely pass ([[diffusion|diffuse]]) between the ISF and blood, and thus both are in [[dynamic equilibrium]] with each other; exchange between the two fluids occurs across the walls of small blood vessels called [[capillary|capillaries]].
[[Image:Illu lymph capillary.png|thumb|300 px|left|Formation of lymph from interstitial fluid (labeled here as "Tissue fluid"). Note: how the tissue fluid is entering the blind ends of lymph capillaries (shown as deep green arrows)]]
ISF forms at the [[arteriole|arterial]] (coming from the heart) end of the capillaries because of higher pressure of blood, and ''most of it'' returns to its [[venule|venous]] ends and [[venule]]s; the rest (10—20%) enters the [[lymph capillary|lymph capillaries]] as lymph.<ref name=grays/> Thus, lymph when formed is a watery clear liquid with the same composition as the ISF. However, as it flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells (particularly, lymphocytes) and proteins.<ref name=sloop>{{cite journal |last= Sloop|first= Charles H.|coauthors= Ladislav Dory, Paul S. Roheim|year= 1987|month= March|title=Interstitial fluid lipoproteins|journal= Journal of Lipid Research|volume= 28|issue= 3|pages= 225—237|id= |url= http://www.jlr.org/cgi/reprint/28/3/225.pdf|accessdate=2008-07-07 |pmid= 3553402}}</ref>
==Lymphatic circulation==
Tubular vessels transport back lymph to the blood ultimately replacing the volume lost from the blood during the formation of the interstitial fluid. These channels are the lymphatic channels or simply called ''lymphatics''. <ref>{{cite web |url=http://www.medterms.com/script/main/art.asp?articlekey=4217 |title=Definition of lymphatics |accessdate=2008-07-06 |work=Webster's New World
Medical Dictionary |publisher= MedicineNet.com|date= }}</ref>
===General structure of Lymphatics===
<!--There's a lot of ambiguity in terminology regarding what is a lymph vessel and what is a capillary, and which have valves, smooth muscles, etc. I'll alter the text when the confusion clears up--[[User:KC Panchal]]-->
The general structure of lymphatics is based on that of [[Blood vessel#Anatomy|blood vessel]]s. There is an inner lining of single flattened cells composed of a type of [[epithelium]] that is called [[endothelium]], and the cells are called ''endothelial cells''. This layer functions to mechanically transport fluid and since the [[basement membrane]] on which it rests is discontinuous, it is quite leaky.<ref name=pepper>{{cite journal | last=Pepper|first=Michael S.|coauthors=Michaela Skobe|date=2003-10-27 | title = Lymphatic endothelium : morphological, molecular and functional properties
| journal= The Journal of Cell Biology| volume = 163 | issue =2 | pages = 209-213| doi = 10.1083/jcb.200308082| url = http://www.jcb.org/cgi/content/full/163/2/209|accessdate=2008-07-06 }}</ref> The next layer is that of [[smooth muscle]]s that are arranged in a circular fashion around the endothelium, which by shortening (contracting) or relaxing alter the diameter (caliber) or the [[lumen]]. The outermost layer is the [[adventitia]] that consists of fibrous tissue. The general structure described here is seen only in larger lymphatics; smaller lymphatics have fewer layers. The smallest vessels (''lymphatic'' or ''[[lymph capillaries]]'') lack both the muscular layer and the outer adventitia. As they proceed forward and in their course are joined by other capillaries, they grow larger and first take on an adventitia, and then smooth muscles.
<!--The text on the whole needs reorganization. Right now, am trying to add as much info as possible, which can later be easily organized into appropriate sections. So, there can be some info that is "overlapping"--[[User:KC Panchal]]-->
The whole lymphatic conducting system broadly consists of two types of channels—the ''initial lymphatics'', the ''prelymphatics'' or ''[[lymph capillaries]]'' that specialize in collection of the lymph from the ISF, and the larger ''lymph vessels'' that propel the lymph forward.
Unlike the cardiovascular system, the lymphatic system is not closed and has no central pump. Lymph movement occurs despite low pressure due to [[peristalsis]] (propulsion of the lymph due to alternate contraction and relaxation of [[smooth muscle]]), valves, and compression during contraction of adjacent skeletal muscle and [[arterial]] [[pulse|pulsation]]<ref name=Shayan2006>{{cite journal | author = Shayan, Ramin; Achen, Marc G.; Stacker, Steven A.
| year = 2006 | title = Lymphatic vessels in cancer metastasis: bridging the gaps | journal Carcinogenesis | volume = 27 | issue = 9 | pages = 1729 | doi = 10.1093/carcin/bgl031 | url = http://carcin.oxfordjournals.org/cgi/content/full/27/9/1729 | pmid = 16597644 }}</ref>.
=== Lymph capillaries ===
[[Image:Lymph vessel.png|thumb|200px|left|Propulsion of lymph through lymph vessel]]
The lymphatic circulation begins <!--at the skin--> with blind ending (closed at one end) highly permeable superficial lymph capillaries, formed by endothelial cells with button-like junctions between them that allow fluid to pass through them when the interstitial pressure is sufficiently high.<ref name=baluk>{{cite journal |last= Baluk|first= Peter|coauthors= Jonas Fuxe, Hiroya Hashizume, Talia Romano, Erin Lashnits, Stefan Butz, Dietmar Vestweber, Monica Corad, Cinzia Molendini, Elisabetta Dejana, and Donald M. McDonald|date= 2007-09-10|title= Functionally specialized junctions between endothelial cells of lymphatic vessels |journal= Journal of Experimental Medicine|volume= 204|issue= 10|pages= 2349-2362|id= 10.1084/jem.20062596|url= http://www.jem.org/cgi/content/full/204/10/2349|pmid=17846148|accessdate=2008-07-07 |quote= }}</ref> These button-like junctions consist of [[Fibrous protein|protein filaments]] like [[CD31|platelet endothelial cell adhesion molecule-1]] or (PECAM-1). <!--When the interstitial fluid volume increases the fenestrae are stretched allowing more fluid to enter the capilaries and restore the interstial fluid to normal levels.<ref name=Shayan2006/>--> A valve system in place here does not allow the absorbed lymph to leak back into the ISF. There is another system of semilunar (''semi''=half; ''lunar''=related to the Moon) valves that does not allow back-flow of lymph along the lumen of the vessel.<ref name=baluk/> Lymph capillaries have many interconnections ([[anastomosis]]) between them, and form a very fine network.<ref name=hollinshead/><!--Like in veins, the [[semilunar valves]] in the lymphatics ensure unidirectional movement of the lymph.-->
Rhythmic contraction of the vessel walls through movements may also help draw fluid into the smallest lymphatic vessels, [[capillary|capillaries]]. <!--Tight clothing can restrict this, thus reducing the removal of wastes and allowing them to accumulate: This is somewhat out of context--[[User:KC Panchal]]--> If tissue fluid builds up the tissue will swell; this is called [[edema]]. As the circular path through the body's system continues, the fluid is then transported to progressively larger lymphatic vessels culminating in the [[right lymphatic duct]] (for lymph from the right upper body) and the [[thoracic duct]] (for the rest of the body); both ducts ''drain'' into the circulatory system at the right and left [[subclavian vein]]s. The system collaborates with white blood cells in lymph nodes to protect the body from being infected by cancer cells, fungi, viruses or bacteria. This is known as a secondary circulatory system.
=== Lymph vessels ===
The lymph capillaries drain the lymph to larger ''contractile'' lymphatics, which have valves as well as smooth muscle walls. These are called the ''collecting [[lymphatics]]''.<ref name=Shayan2006/> As the collecting lymph vessel accumulates lymph from more and more lymph capillaries in its course, it become larger and is called the [[afferent lymph vessel]] as it enters a lymph node. Here the lymph percolates through the lymph node tissue and is removed by the [[efferent lymph vessel]]. An efferent lymph vessel my directly drain into one of the ([[Right lymph duct|right]] or [[Thoracic duct|thoracic]]) lymph ducts, or may empty another lymph node as its afferent lymph vessel.<ref name=hollinshead>{{cite book |last= Rosse|first= Cornelius|coauthors= Penelope Gaddum-Rosse|title= Hollinshead's Textbook of Anatomy|origyear= 1962|accessdate= 2008-07-09|edition= Fifth Edition|year= 1997|publisher= Lippincott-Raven|location= Philadelphia|isbn= 0-397-51256-2|pages= 72—73|chapter= The Cardiovascular System (Chapter 8)}}</ref> Both the lymph ducts return the lymph to the blood stream by emptying into the [[subclavian vein]]s
The functional unit of a lymph vessel is known as a ''[[lymphangion]]'' that is the segment between two valves. Since, it is contractile, depending upon ratio of its length:radius, it can act like a contractile chamber propelling the fluid ahead, or as a resistance vessel tending to stop the lymph in its place.<ref name=venu>{{Citation
| first = A.M.
| last = Venugopal
| author-link =
| first2 = R.H.
| last2 = Stewart
| first3 = G.A.
| last3 = Laine
| first4 = C.M.
| last4 = Quick
| contribution = Optimal Lymphatic Vessel Structure
| contribution-url = http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=1404039
| title = 26th Annual International Conference of the IEEE
| volume = 2
| year = 2004
| pages = 3700—3703
| place =
| publisher = Engineering in Medicine and Biology Society
| url = http://ieee.org/portal/site
| doi =
| id = }}</ref>
== Lymphoid tissue ==
Lymphoid tissue associated with the lymphatic system is concerned with immune functions in defending the body against the [[infection]]s and spread of [[tumor]]s. It consists of [[connective tissue]] with various types of white blood cells enmeshed in it, most most numerous being the [[lymphocyte]]s.
The lymphoid tissue may be primary, secondary or tertiary depending upon what stage of lymphocyte development and maturation it is involved in. The [[thymus]] and the [[bone marrow]] constitute the primary lymphoid tissue that is involved in the production and early [[clonal selection|selection]] of lymphocytes. Secondary lymphoid tissue provides the environment for the foreign or altered native molecules ([[antigen]]s) to interact with the lymphocytes. It is exemplified by the [[lymph node]]s, and the lymphoid follicles in [[tonsil]]s, [[Peyer's patch]]es, etc. that are associated with the [[mucosa-associated lymphoid tissue]] (MALT). The tertiary lymphoid tissue typically contains much fewer lymphocytes, and assumes an immune role only when challenged with antigens that result in [[inflammation]]. This it achieves by importing the lymphocytes from blood and lymph.<ref name=goldsby>{{cite book
| last = Goldsby
| first = Richard
| coauthors = Kindt, TJ; Osborne, BA; Janis Kuby
| title = Immunology
| edition = Fifth Edition
| chapter = Cells and Organs of the Immune System (Chapter 2)
| origyear= 1992
| publisher = W. H. Freeman and Company
| date = 2003
| location = New York
| pages= 24—56
| isbn = 07167-4947-5}}</ref>
=== Lymph nodes ===
{{details3|[[lymph node]]}}
[[Image:Illu lymph node structure.png|thumb|350px|right|A lymph node showing [[Afferent lymph vessel| afferent]] and [[Efferent lymph vessel| efferent]] [[lymphatic vessel]]s]]
A lymph node is an organized collection of lymphoid tissue, through which the lymph passes on its way to returning to blood. Lymph nodes are located at intervals along the lymphatic system. Several [[Wiktionary:afferent|afferent]] lymph vessels bring in lymph, which percolates through the substance of the lymph node, and is drained out by an [[Wiktionary:efferent|efferent]] lymph vessel.
The substance of lymph node consists of lymphoid follicles in the outer portion called the ''[[Wiktionary:cortex|cortex]]'', which contains the lymphoid follicles, and an inner portion called ''[[Wiktionary:medulla|medulla]]'', which is surrounded by the cortex from all sides except for a portion known as the ''[[Wiktionary:hilum|hilum]]''. The hilum presents as a depression on the surface of the lymph node, which makes the otherwise spherical or ovoid lymph node bean-shaped. The efferent lymph vessel directly emerges from the lymph node here. The arteries and veins supplying the lymph node enter and exit through the hilum.
Lymph follicles are a dense collection of lymphocytes, the number, sized and configuration of which change in accordance with the functional state of the lymph node, e.g., the follicles expand significantly upon encountering a foreign antigen. The selection of B cells occurs in the germinal center of the lymph nodes.
Lymph nodes are particularly numerous in the [[mediastinum]] in the chest, neck, pelvis, axilla (armpit), inguinal (groin) region, and in association with the blood vessels of the intestines.<ref name=grays/>
==Function of the fatty acid transport system==
[[Lymph vessel]]s called [[lacteals]] are present in the lining of the [[gastrointestinal tract]], predominantly in the small intestine. While most other nutrients absorbed by the [[small intestine]] are passed on to the portal venous system to drain, via the [[portal vein]], into the [[liver]] for processing, fats (lipids) are passed on to the lymphatic system, to be transported to the blood circulation via the [[thoracic duct]]. The enriched lymph originating in the lymphatics of the [[small intestine]] is called [[chyle]]. As the blood circulates, fluid leaks out into the body tissues. This fluid is important because it carries food to the cells and waste back to the bloodstream. The nutrients that are released to the circulatory system are processed by the [[liver]], having passed through the systemic circulation. The lymph system is a one-way system, transporting interstitial fluid back to blood.
==Diseases of the lymphatic system==
[[Lymphedema]] is the [[oedema |swelling]] caused by the accumulation of lymph fluid.<ref>{{Citation
| title = Lymphedema
| url = http://www.merck.com/mmhe/sec03/ch037/ch037b.html
}}</ref>, which may occur if the lymphatic system is damaged, or has malformations. It usually affects the limbs, though face, neck and abdomen may also be affected. An estimated 170 million people develop lymphedema, which progresses in three stages:
<br />'''Stage 1''': Pressing the swollen limb leaves a pit that takes a while to fill back in. Because there is little fibrosis (hardening) it is often reversible. Elevation reduces swelling.
<br />'''Stage 2''': Pressure does not leave a pit. Elevation does not help. If left untreated, the limb becomes fibrotic.
<br />'''Stage 3''': This stage of lymphedema is often called elephantiasis. It is generally only in the legs after lymphedema that has gone long untreated. While treatment can help a little, it is not reversible.
Some common causes of swollen lymph nodes include [[infection]]s, [[infectious mononucleosis]] and [[cancer]], e.g. [[Hodgkin's lymphoma|Hodgkin's]] and [[non-Hodgkin's lymphoma]], and [[metastasis]] of cancerous cells via the lymphatic system.
In [[elephantiasis]], infection of the lymphatic vessels cause a thickening of the skin and enlargement of underlying tissues, especially in the legs and genitals. It is most commonly caused by a [[parasitic disease]] known as [[lymphatic filariasis]].
[[Lymphangiosarcoma]] is a malignant soft tissue tumor ([[soft tissue sarcoma]]), whereas [[lymphangioma]] is a benign tumor occurring frequently in association with [[Turner syndrome]]. [[Lymphangioleiomyomatosis]] is a benign tumor of the smooth muscles of the lymphatics that occurs in the [[lung]]s.
==Development of lymphatic tissues==
Lymphatic tissues begin to develop by the end of the fifth week of embryonic life. Lymphatic vessels develop from lymph sacs that arise from developing veins, which are derived from [[mesoderm]].
The first lymph sacs to appear are the paired jugular lymph sacs at the junction of the internal jugular and subclavian veins. From the jugular lymph sacs, lymphatic capillary plexuses spread to the thorax, upper limbs, neck and head. Some of the plexuses enlarge and form lymphatic vessels in their respective regions. Each jugular lymph sac retains at least one connection with its jugular vein, the left one developing into the superior portion of the thoracic duct.
The next lymph sac to appear is the unpaired retroperitoneal lymph sac at the root of the mesentery of the intestine. It develops from the primitive vena cava and mesonephric veins. Capillary plexuses and lymphatic vessels spread form the retroperitoneal lymph sac to the abdominal viscera and diaphragm. The sac establishes connections with the cisterna chyli but loses its connections with neighboring veins.
The last of the lymph sacs, the paired posterior lymph sacs, develop from the iliac veins. The posterior lymph sacs produce capillary plexuses and lymphatic vessels of the abdominal wall, pelvic region, and lower limbs. The posterior lymph sacs join the [[cisterna chyli]] and lose their connections with adjacent veins.
With the exception of the anterior part of the sac from which the cisterna chyli develops, all lymph sacs become invaded by mesenchymal cells and are converted into groups of [[lymph nodes]].
The [[spleen]] develops from mesenchymal cells between layers of the dorsal mesentery of the stomach. The [[thymus]] arises as an outgrowth of the third pharyngeal pouch.
==History==
[[Image:Galen.jpg|thumb|300px|right|Claudius Galenus of Pergamum (131-201 AD), better known as Galen, was an ancient Greek physician]]
[[Hippocrates]] was one of the first persons to mention the lymphatic system in fifth century BC. In his work "On Joints," he briefly mentioned the lymph nodes in one sentence. Rufus of [[Ephesus]], a Roman physician, identified the axillary, inguinal and mesenteric lymph nodes as well as the thymus during the first to second century AD.<ref name=Ambrose2006>{{cite journal | author = Ambrose, C. | year = 2006 | title = Immunology’s first priority dispute—An account of the 17th-century Rudbeck–Bartholin feud | journal = Cellular Immunology | volume = 242 | pages = 1 | doi = 10.1016/j.cellimm.2006.09.004 }}</ref> The first mention of lymphatic vessels was in 3rd century BC by Herophilius, an Egyptian anatomist, who incorrectly concluded that the "absorptive veins of the lymphatics", by which he meant the [[lacteals]] (lymph vessels of the intestines), drained into the [[hepatic portal vein]]s, and thus into the liver.<ref name=Ambrose2006/> Findings of Ruphus and [[Herophilus]] findings were further propagated by the Greek physician [[Galen]], who described the lacteals and mesenteric lymph nodes which he observed in his dissection of apes and pigs in the second century A.D.<ref name=Ambrose2006/><ref name=fanous/>
Till the seventeenth century ideas of Galen were most prevalent. And accordingly, it was believed that the blood was produced by the liver from chyle contaminated with ailments by the intestine and stomach, to which various spirits were added by other organs, and that this blood was consumed by all the organs of the body. This theory required that the blood be consumed and produced many times over. His ideas had remained unchallenged till the seventeenth century, and even then were defended by some physicians.<ref name=fanous>{{cite journal|last=Fanous|first=Medhat YZ|coauthors=Anthony J Phillips, John A Windsor|title=Mesenteric Lymph: The Bridge to Future Management of Critical Illness|year=2007|journal=Journal of the Pancreas|volume=8|issue=4|pages=374—399|url=http://www.joplink.net/prev/200707/06.html|publisher=Department of Internal Medicine and Gastroenterology
ALMA MATER STUDIORUM - UNIVERSITY OF BOLOGNA|accessdate=2008-07-11}}</ref>
[[Image:Olaus Rudbeck Sr (portrait by Martin Mijtens Sr, 1696).jpg|thumb|200px|left|Olaus Rudbeck in [[1696]]]]
In the mid 16th century [[Gabriel Fallopius]] (discoverer of the [[Fallopian Tube]]s) described, what are now known as the lacteals as "coursing over the intestines full of yellow matter."<ref name=Ambrose2006/> In about 1563, [[Bartolomeo Eustachi]] a professor of anatomy, described the thoracic duct in horses as ''vena alba thoracis.''<ref name=Ambrose2006/> The next breakthrough came when in [[1622]], physician [[Gasparo Aselli]], identifed lymphatic vessels of the intestines in dogs and termed them ''venae alba et lacteae,'' which is now known as simply the lacteals. The lacteals were termed the fourth kind of vessels (the other three being the artery, vein and nerve,which was then believed to be a type of vessels), and disproved Galen's one idea wrong: that chyle was carried by the veins. But, he still believed that the lacteals carried the chyle to the liver (as taught by Galen).<ref name=flourens>{{cite book|last=Flourens|first=P.|year=1859|title=A History of the Discovery of the Circulation of the Blood|chapter=ASELLI, PECQUET, RUDBECK, BARTHOLIN (Chapter 3)|pages=67—99|url=http://books.google.com/books?id=4QqS6LrYWf4C&printsec=frontcover&dq=william+harvey&as_brr=1&source=gbs_similarbooks_r&cad=2_1#PPA67,M1|publisher=Rickey, Mallory & company|accessdate=2008-07-11}}</ref> He also also identified the thoracic duct but failed to notice its connection with the lacteals.<ref name=Ambrose2006/> This connection was established by [[Jean Pecquet]] in the [[1651]], who found a white fluid mixing with blood in a dog's heart. He suspecte that fluid to be [[chyle]] as its flow of increased when abdominal pressure was applied. He traced this fluid to the thoracic duct, which he then followed to a chyle filled sac he called the ''chyli receptaculum,'' which is now know as the cisternae chyli; further investigations led him find that lacteals contents enter the venous system via the thoracic duct.<ref name=Ambrose2006/><ref name=flourens/> Thus, it was proven convincingly that the lacteals did not terminate in the [[liver]] thus disproving Galen's second idea that the chyle flowed to the liver.<ref name=flourens/> [[Johann Veslingius]] drew the earliest sketches of the lacteals in humans in [[1647]].<ref name=fanous/>
[[Image:Thomas bartholin.jpg|thumb|right|150px|Thomas Bartholin]]
The idea that blood recirculates through the body rather than being produced anew by the liver and the heart was first accepted as a result of works of [[William Harvey]]—a work he published in [[1628]]. In [[1652]], [[Olaus Rudbeck]] (1630—1702), a Swedish discovered certain transparent vessels in the liver that contained clear fluid (and not white), and thus named them ''hepatico-aqueous vessels''. He also learned that they emptied into the thoracic duct, and that they had valves.<ref name=flourens/> He announced his findings in the court of Queen [[Christina of Sweden]], but did not publish his findings for a year,<ref name=eriksson>{{cite journal|last=Eriksson|first=G.|title=Olaus Rudbeck as scientist and professor of medicine (Original article in Swedish)|year=2004|volume=8|issue=1|pages=39—44|journal= Svensk Medicinhistorisk Tidskrift|laguage= Swedish|accessdate=2008-07-11}}</ref> and in the interim similar findings were published by [[Thomas Bartholin]], who additionally published that such vessels are present every where in the body, and not just the liver. He is also the one to have named them ''"lymphatic vessels"''. <ref name=flourens/>. This had resulted in a bitter dispute between one of Bartholin's pupils, Martin Bogdan<ref>{{cite web |url= http://www.ilab.org/db/detail.php?booknr=349906004|title= Disputatio anatomica, de circulatione sanguinis|accessdate=2008-07-11 |work= Account of Rudbeck's work on lymphatic system and dispute with Bartholin|publisher= The International League of Antiquarian Booksellers|accessdate= 2008-07-11}}</ref> and Rudbeck, who he accused of [[plagiarism]]. <ref name=eriksson/>
==See also==
* [[Lymphangiogenesis]]
* [[Lymphedema]]
* [[Lymphoma]]
* [[American Society of Lymphology]]
* [[Manual lymphatic drainage]]
==References==
{{reflist|2}}
==External links==
{{commonscat|Lymphatic system}}
*[http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookIMMUN.html Lymphatic System]
*[http://www.innerbody.com/image/lympov.html Lymphatic System Overview] (innerbody.com)
{{Immune system}}
{{organ_systems}}
{{Lymphatic flow}}
{{lymphatic_system}}
{{Lymphatics of head and neck}}
{{Lymphatics of upper limbs}}
{{Lymphatics of torso}}
{{Lymphatics of lower limbs}}
[[Category:Lymphatic system|*]]
[[Category:Anatomy]]
[[Category:Medicine]]
[[Category:Cardiovascular system]]
[[Category:Pathology]]
[[ar:جهاز لمفاوي]]
[[ca:Sistema limfàtic]]
[[cs:Lymfatická soustava]]
[[da:Lymfesystem]]
[[de:Lymphsystem]]
[[el:Λεμφικό σύστημα]]
[[es:Sistema linfático]]
[[fr:Système lymphatique]]
[[ko:림프계]]
[[id:Sistem limfatik]]
[[ia:Systema lymphatic]]
[[is:Sogæðakerfið]]
[[it:Sistema linfatico]]
[[he:מערכת הלימפה]]
[[la:Systema lymphaticum]]
[[lv:Limfrites sistēma]]
[[mk:Лимфен систем]]
[[nl:Lymfevatenstelsel]]
[[ja:リンパ系]]
[[no:Lymfesystem]]
[[pl:Układ limfatyczny]]
[[pt:Sistema linfático]]
[[ru:Лимфатическая система]]
[[sr:Лимфни систем]]
[[fi:Imusuonisto]]
[[sv:Lymfatiska systemet]]
[[tl:Sistemang limpatiko]]
[[tr:Lenfatik sistem]]
[[ur:نظام سیالہ]]
[[yi:לימפעטיק סיסטעם]]
[[zh:淋巴系統]]