Lymph Capillaries

Lymph capillaries form as collecting tubes from tissue canals in the interstitial space. Lymph capillaries are very small vessels without valves. They usually form drainage systems. Lymph capillaries have extremely thin walls.  Their walls consist of only one layer of lymphatic endothelial cells, which are flattened like wallpaper. There is no basal membrane. Instead, electron microscopy shows a layer of matted 10 nm-thick filaments underneath the epithelium in its place. From these felted filaments emerge anchor filaments,  which reach to the endothelial cells of the lymph capillary on one side and to the connective tissue on the other side. The matte d sub endothelial fibers are collagen f ibers, types IV and VI, among others. The adjacent lymph capillary from the nasal mucous membrane (rat) contains several lymphocytes. Labels indicate easily recognizable sub endothelial matted fibers. Lymph capillaries turn into collector lymph vessels . Their walls contain a basal membrane and contractile myocytes. Collector lymph vessels also contain valves .

1 Endothelium

2 Endothelial cell nucleus

3 Connective tissue cells (fibrocytes)

Electron microscopy; magnification: × 4000

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgart · New York .