Editing Lymphatic system (section)

==Development==
{{unsourced|section|date=December 2024}}
The development of the lymphatic vascular system is a highly coordinated process essential for maintaining fluid [[homeostasis]], [[immune surveillance]], and lipid absorption. [[Lymphangiogenesis]], the formation of lymphatic vessels from pre-existing ones, is primarily driven by the migration and differentiation of lymphatic [[endothelial cells]] (LECs) under the influence of molecular signals such as vascular endothelial growth factor C ([[VEGF-C]]).The maturation and specialization of lymphatic vessels involve complex interactions with surrounding tissues, ensuring the proper function of lymphatic drainage and [[Immune cell trafficking]]. Recent advances in vitro and in vivo studies have provided deeper insights into the mechanisms regulating lymphatic vascular development, as well as the processes governing its maintenance and aging. Understanding these pathways is critical, as disruptions in lymphatic development are implicated in [[congenital disorders]], inflammatory diseases,<ref>{{Cite journal |last1=Hokari |first1=Ryota |last2=Tomioka |first2=Akira |date=2021-08-17 |title=The role of lymphatics in intestinal inflammation |journal=Inflammation and Regeneration |volume=41 |issue=1 |pages=25 |doi=10.1186/s41232-021-00175-6 |doi-access=free |issn=1880-8190 |pmc=8371859 |pmid=34404493}}</ref> and [[cancer metastasis]].

Lymphatic tissues begin to develop by the end of the fifth week of embryonic development. 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 vein|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 [[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.<ref>{{Cite journal |last1=González-Loyola |first1=Alejandra |last2=Petrova |first2=Tatiana V. |date=February 2021 |title=Development and aging of the lymphatic vascular system |journal=Advanced Drug Delivery Reviews |language=en |volume=169 |pages=63–78 |doi=10.1016/j.addr.2020.12.005|doi-access=free |pmid=33316347 }}</ref>