Lymphatic system

Lymph capillaries (green)

The lymphatic system ( lat. - . Anat Systema lymphaticum , Systema lymphoideum , Systema lymphaceum , lymphare Systema or lymphatic system ; lymph  . = "Body of water", to lat lympha , clear water ') is part of the defense system ( immune system ) of vertebrates against Pathogens , foreign particles and pathologically altered body components (e.g. tumor cells). It is divided into the lymphatic organs and the lymphatic system. In addition to its function in the immune system, the lymphatic system also plays an important role in the transport of fluids and is closely related to the blood circulation .

Lymphatic organs

The lymphatic organs are specialized organs for the differentiation and multiplication of the lymphocytes . They are divided into primary and secondary lymphatic organs.

In the primary lymphatic organs , precursor cells are differentiated into immunocompetent T or B lymphocytes :

• Thymus
• Bone marrow or bursa-equivalent organ in mammals, Bursa Fabricii in birds

In the secondary lymphoid organs , a specific immune response is triggered by the meeting of antigens and immunocompetent lymphocytes:

• Lymph follicle
• Peyer's plaques
• Tonsils ("almonds")
• spleen
• Lymph nodes
• Appendix (appendix to the cecum , often wrongly referred to the Wurmfortsatzresektion as the "appendix")

The spleen and bone marrow also take on functions in the formation, storage and breakdown of blood.

According to the tissue composition, a distinction is made between lymphoepithelial and lymphoreticular organs .

Lymphatic system

→ Main article : lymphatic vessel

The human lymphatic system without the meninges

The lymphatic system begins as lymph capillaries in the periphery, so these end "blind". The lymph capillaries unite to form larger lymph vessels . The lymph nodes are integrated into these lymph vessels as filter stations. As a result, lymph vessels also serve to spread the lymphocytes . The lymph vessels unite to form lymphatic collecting trunks , which open into the vein corners and thus into the superior vena cava and thus into the venous system . In contrast to the blood circulation , there is no “lymph circulation”. About 2 liters of lymph fluid are transported in the lymphatic system every day. The transport of the lymphatic fluid takes place either passively through the movement of the limbs and the compression of the lymph vessels or actively through the disordered contractions of the individual lymphangions (lymph heart). Lymphangione are sections of lymphatic vessels with a thickened wall, bounded by valve flaps, the smooth muscles of which contract about ten times per minute. The lymph fluid then follows the least resistance in the direction of the proximally widening lymph vessels. By a manual drainage and intermittent pneumatic compression the lymphangion can be stimulated and thus about sixty times per minute contract.

In addition to its importance in lymphocyte circulation, the lymphatic system plays an important role in the evacuation of fluids from various parts of the body. Parts of the blood emerge in the capillary bed of the tissues as intercellular fluid (tissue water). This tissue fluid is drained on the one hand via the veins , on the other hand, however, as lymph via the lymphatic vessels. The fluid transported via the lymphatic system finally flows into the superior vena cava , which reunites both body fluids (lymph and blood). The fats absorbed in the intestine are also transported into the bloodstream via the lymphatic system .

Recess of the brain and spinal cord

→ Main article : Glymphatic system

For the special protection of the brain and spinal cord ( CNS ) there are not only the filter systems of the blood-brain barrier and the blood-liquor barrier , but also the lockout of the lymphatic system. From the outside it only extends into the meninges . There, however, there is a supply from the brain's own disposal system, the glymphatic system , whereby the CNS is also indirectly connected to the lymphatic system.

See also

• Organ system

literature

• Uwe Gille: Cardiovascular and immune system, Angiologia . In: F.-V. Salomon et al. (Ed.): Anatomy for veterinary medicine . Enke-Verlag Stuttgart, 2nd edition 2008, pp. 404–463. ISBN 978-3-8304-1075-1

Web links

Commons : Lymphatic System  - collection of images, videos and audio files

Wiktionary: Lymphsystem  - explanations of meanings, word origins, synonyms, translations

Individual evidence

1. ^ W. His: The anatomical nomenclature. Nomina Anatomica. The anatomical society on its IX. At the meeting in Basel. Veit & Comp., Leipzig 1895.
2. ↑ Federative Committee on Anatomical Terminology (FCAT): Terminologia Anatomica. Thieme, Stuttgart 1998.
3. ↑ AJP van den Broek, J. Boeke, JAJ Barge: Leerboek der Beschrijvende ontleedkunde van de mens. Deel I. Divisiveness of ontleedkunde, moving organs, vaatstelsel. 8th edition. NVA Oosthoek's Uitgeverij Mij., Utrecht 1954 ( Dutch ).
4. ^ H. Triepel: Nomina Anatomica. With the support of specialist philologists. JF Bergmann publishing house, Wiesbaden 1910.
5. ^ CT Lewis, C. Short: A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary. Clarendon Press, Oxford 1879 ( English ).
6. ^ NA Jessen, AS Munk, I. Lundgaard, M. Nedergaard: The Glymphatic System: A Beginner's Guide. In: Neurochemical research. Volume 40, number 12, December 2015, pp. 2583-2599, doi : 10.1007 / s11064-015-1581-6 , PMID 25947369 , PMC 4636982 (free full text) (review).
7. ↑ D. Raper, A. Louveau, J. Kipnis: How Do Meningeal Lymphatic Vessels Drain the CNS? In: Trends in neurosciences. Volume 39, number 9, September 2016, pp. 581-586, doi : 10.1016 / j.tins.2016.07.001 , PMID 27460561 , PMC 5002390 (free full text) (review).

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