The lymphatic device parallels the cardiovascular mechanism (see the photos below). The lymphatic device is unique, in that it is a 1-way mechanism that return lymph liquid via ship to the cardiovascular mechanism for eventual elimination of toxic byproducts by end organs, such as the kidney, liver, colon, skin, and also lungs.

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Lymph nodes and also vessels, anterior view.
Lymphatic system, anterior view.




Contains nutrients, oxygen, hormones, and also fatty acids, and toxins and cellular garbage products, that room transported to and from cellular tissues

Lymphatic vessels

Transport lymph native peripheral tissues to the veins that the cardiovascular system

Lymph nodes

Monitors the composition of lymph, the ar of microorganism engulfment and eradication, the immunologic response, and also the regulation site


Monitors the composition of blood components, the location of virus engulfment and also eradication, the immunologic response, and also the regulation site


Serves as the website of T-lymphocyte maturation, development, and control

The lymphatic system’s main features are as follows:

Restoration of overabundance interstitial fluid and also proteins come the blood

Absorption that fats and also fat-soluble vitamins from the digestive system and also transport the these facets to the venous circulation


Gross Anatomy


Lymph is a fluid obtained from blood plasma. It is moved out with the capillary wall surface by push exerted by the heart or by osmotic push at the to move level. Lymph includes nutrients, oxygen, and hormones, as well as toxins and also cellular waste products generated through the cells. As the interstitial liquid accumulates, that is picked up and removed by lymphatic vessels the pass with lymph nodes, i beg your pardon return the liquid to the venous system. As the lymph passes v the lymph nodes, lymphocytes and also monocytes go into it.

At the level that the cradle (GI) tract, lymph has actually a milky consistency that is attributable to fat acids, glycerol, and rich fat content. Lacteals are lymph vessels that carry intestinal fat and are localized to the GI tract. <1, 5, 3>

Lymphatic vessels

Lymphatic capillaries room blind-ended tubes with thin endothelial wall surfaces (only a solitary cell in thickness). They room arranged in one overlapping pattern, for this reason that pressure from the bordering capillary pressures at these cells allows fluid to get in the capillary (see the picture below). The lymphatic capillaries coalesce to form larger meshlike networks that tubes the are situated deeper in the body; these are recognized as lymphatic vessels.

Lymph capillaries in spaces. Blind-ended lymphatic capillaries arise within interstitial spaces of cells near arterioles and venules.
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The lymphatic vessels thrive progressively bigger and form 2 lymphatic ducts: the best lymphatic duct, i m sorry drains the upper right quadrant, and the thoracic duct, i m sorry drains the remaining lymphatic tributaries. Prefer veins, lymphatic vessels have 1-way valves to prevent any kind of backflow (see the image below). The push gradients that relocate lymph through the ship come indigenous skeletal muscle action, smooth muscle contraction within the smooth muscle wall, and also respiratory movement. <1, 6, 2, 5, 4, 7>

Lymphatic 1-way valves.
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Lymph nodes

Lymph nodes room bean-shaped frameworks that are widely distributed throughout the lymphatic pathway, giving a filtration device for the lymph before it rejoins the blood stream. The average person body contains about 600-700 of them, predominantly focused in the neck, axillae, groin, thoracic mediastinum, and mesenteries that the GI tract. Lymph nodes constitute a main line the defense by hosting 2 varieties of immunoprotective cell lines, T lymphocytes and B lymphocytes.

Lymph nodes have actually 2 unique regions, the cortex and also the medulla. The cortex includes follicles, which are collections the lymphocytes. In ~ the facility of the follicles is one area dubbed germinal centers that predominantly hold B-lymphocytes if the continuing to be cells the the cortex space T-lymphocytes. Ship entering the lymph nodes are called afferent lymphatic ship and, likewise, those exiting are called efferent lymphatic vessels (see the photo below).

Lymph node structure.
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Extending native the collagenous capsule inward throughout the lymph node space connective organization trabeculae the incompletely divide the an are into compartments. Deep in the node, in the medullary portion, the trabeculae divide repeatedly and also blend right into the connective organization of the hilum that the node. Therefore the capsule, the trabeculae, and the hilum comprise the framework of the node. Within this framework, a delicate plan of connective tissue develops the lymph sinuses, within which lymph and free lymphoid aspects circulate.

A subcapsular or marginal sinus exists in between the capsule and also the cortex the the lymph node. Lymph overcome from the subcapsular sinus into the cortical sinus toward the medulla that the lymph node. Medullary sinuses stand for a large network the lymph channels that drain toward the hilum of the node; native there, lymph is built up into number of efferent ship that run to various other lymph nodes and also eventually drain into their respective lymphatic ducts (see the image below). <1, 6>

Lymph drainage flow; lymphatic duct anatomy.
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The thymus is a bilobed lymphoid organ located in the exceptional mediastinum of the thorax, posterior to the sternum. After ~ puberty, it begins to diminish in size; it is small and fat in adults after degeneration.

The primary function of the thymus is the processing and maturation that T lymphocytes. If in the thymus, T lymphocytes execute not respond come pathogens and also foreign organisms. After ~ maturation, they go into the blood and also go to other lymphatic organs, whereby they help administer defense. Structurally, the thymus is similar to the spleen and also lymph nodes, with many lobules and also cortical and also medullary elements. It likewise produces thymosin, a hormone that helps wake up maturation of T lymphocytes in other lymphatic organs. <2, 5, 3, 4>


The spleen, the biggest lymphatic organ, is a convex lymphoid framework located listed below the diaphragm and behind the stomach. The is surrounded by a connective organization capsule the extends inward to division the organ into lobules consisting of cells, little blood vessels, and also 2 types of tissue well-known as red and white pulp. Red pulp is composed of venous sinuses filled v blood and also cords that lymphocytes and also macrophages; white pulp is lymphatic tissue consisting that lymphocytes about the arteries. Lymphocytes are densely packed in ~ the cortex that the spleen.

The spleen filter blood in lot the same method that lymph nodes filter lymph. Lymphocytes in the spleen reaction to pathogens in the blood and attempt to ruin them. Macrophages climate engulf and also phagocytose damaged cells and also cellular debris. The spleen, together with the liver, eradicates damaged and old erythrocytes indigenous the blood circulation. Like various other lymphatic tissue, that produces lymphocytes in one immunologic solution to offending pathogens. <5, 3, 4>

Therefore, the spleen conducts several essential functions, as follows:

It serves together a reservoir that lymphocytes for the body

It filters blood

It plays crucial role in red blood cell and also iron metabolism through macrophage phagocytosis that old and also damaged red blood cell

It recycles stole by sending out it come the liver

It serves as a storage reservoir because that blood

It includes T lymphocytes and B lymphocytes because that immunologic response


Tonsils room aggregates of lymph node tissue located under the epithelial lining of the oral and pharyngeal areas. The main locations are the palatine tonsils (on the political parties of the oropharynx), the pharyngeal tonsils (on the roof of the nasopharynx; also known together adenoids), and the lingual tonsils (on the base of the posterior surface ar of the tongue).

Because this tonsils room so closely related come the oral and also pharyngeal airways, they may interfere through breathing once they come to be enlarged. The predominance of lymphocytes and also macrophages in these tonsillar tissues supplies protection versus harmful pathogens and also substances the may go into through the oral cavity or airway. <1, 2>


Other Considerations

Diseases of the lymphatic system encompass lymphedema, lymphoma, lymphadenopathy, lymphadenitis, filariasis, splenomegaly, and also tonsillitis.


Lymphedema results once the lymphatic device cannot adequately drain lymph, bring about an build-up of liquid that causes swelling. It may be either main or secondary.

Primary lymphedema is an inherited problem that occurs as a an outcome of impaired or missing lymphatic vessels; it might be existing at birth, may build with the start of puberty, or may happen in adulthood, with no evident causes

Treatment consists of compression bandages or pneumatic stockings to reduce the swelling after appropriate diagnosis is made. <9, 4>


Lymphoma is a clinical term supplied for a team of cancers that originate in the lymphatic system. Lymphomas usually begin with malignant revolution of the lymphocytes in lymph nodes or bunches of lymphatic tissue in organs favor the stomach or intestines. Hodgkin lymphoma and also non-Hodgkin lymphoma space the 2 significant categories that lymphoma, identified by enlargement the lymph nodes, usually present in the neck. Symptom of lymphoma incorporate chronic fatigue, weak immune function, load loss, and also night sweats. <4>


Lymphadenopathy is a lymphatic disorder in i m sorry the lymph nodes come to be swollen or enlarged together a consequence of an infection. For example, swollen lymph nodes in the neck may happen as a an outcome of a throat infection or sinus infection. <3>


Lymphadenitis is one inflammation of the lymph node that is as result of a bacterial infection of the tissue in the node, which causes swelling, reddening, and also tenderness that the skin overlying the lymph node. <3>


Filariasis is a lymphatic mechanism disorder that results from a helminth infection that causes lymphatic insufficiency. <3>


Splenomegaly, or enlarged spleen, is a lymphatic device disorder that establishes as a result of a viral infection, such together mononucleosis.


Tonsillitis is brought about by an epidemic of the tonsils (the lymphoid tissues current in the earlier of the dental cavity). The tonsils help filter out bacteria; when infected, they come to be swollen and also inflamed, causing sore throat, fever, and challenge and pain while swallowing. <3>


Alcamo E, Krumhardt B. Anatomy & Physiology. The simple Way. Barron"s; 2005.

Marieb E, Hoehn K. Human Anatomy & Physiology. 8th. 2010.

Molander DW. Diseases of the Lymphatic system- Diagnosis and also Therapy. 1983.

Kindt TJ, Goldsby RA, Osborne BA, Kuby J. Kuby Immunology. 2007.

Klein E. Anatomy that Lymphatic system. 2010.

Media gallery
Lymph nodes and vessels, anterior view.
Lymphatic system, anterior view.
Lymph capillaries in spaces. Blind-ended lymphatic capillaries arise in ~ interstitial spaces the cells close to arterioles and venules.
Lymphatic 1-way valves.
Lymph node structure.
Lymph drainage flow; lymphatic duct anatomy.
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Table 1. Vital Components the Lymphatic device




Contains nutrients, oxygen, hormones, and also fatty acids, and also toxins and cellular rubbish products, that room transported to and also from moving tissues

Lymphatic vessels

Transport lymph from peripheral organization to the veins the the cardiovascular system

Lymph nodes

Monitors the composition of lymph, the ar of microorganism engulfment and eradication, the immunologic response, and the regulation site


Monitors the composition of blood components, the location of microorganism engulfment and also eradication, the immunologic response, and also the regulation site


Serves together the site of T-lymphocyte maturation, development, and also control

earlier to list
Contributor Information and Disclosures

Praveen Buddiga, MD, FAAAAIPhysician, Allergy, Asthma and also Immunology, Founder, family Allergy Asthma Clinic; Assistant Clinical Professor, Fresno Medical education and learning Program, college of California, san Francisco, college of medicine Praveen Buddiga, MD, FAAAAI is a member the the adhering to medical societies: American Academy that Allergy Asthma and Immunology, American university of Allergy, Asthma and also Immunology, California medical AssociationDisclosure: Serve(d) together a speaker or a member that a speakers bureau for: PFIZER; GLAXO-SMITH-KLINE; ASTRA-ZENECA; MYLAN; TEVA RESPIRATORY; ALCON OPHTHALMICS; MERCK RESPIRATORY.

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chief Editor

Thomas R Gest, PhDProfessor the Anatomy, college of Houston college of medication Thomas R Gest, phd is a member the the adhering to medical societies: American combination of Clinical AnatomistsDisclosure: Nothing come disclose.

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