Anatomy and Physiology of the Nasolacrimal Ducts
The human efferent tear ducts are part of the lacrimal system. They consist of the upper and the lower lacrimal canaliculus, the lacrimal sac, and the nasolacrimal duct. As a draining and secretory system, the nasolacrimal ducts play a decisive role in tear transport and nonspecific immune defense. In this context the integrity of the mucosa as source of mucins and trefoil factor family peptides is of great importance with regard to tear drainage. Moreover, components of tear fluid are absorbed by the epithelium of the nasolacrimal passage and are transported into a surrounding vascular system. This system is comparable to a cavernous body that is subject to autonomic control and regulates tear outflow. Tear duct-associated lymphoid tissue (TALT) is present in the efferent tear ducts, displaying the cytomorphological and immunophenotypic features of mucosa-associated lymphoid tissue (MALT).
KeywordsOcular Surface Lacrimal Gland Nasolacrimal Duct Meibomian Gland Lacrimal Duct
Unable to display preview. Download preview PDF.
- 9.Paulsen F (2003) The nasolacrimal ducts. Adv Anat Embryol Cell Biol 170:1–106Google Scholar
- 26.Tillmann B (2005) Atlas der Anatomie. Springer, Berlin Heidelberg, New YorkGoogle Scholar
- 27.Lüllmann Rauch R (2003) Histologie. Thieme, StuttgartGoogle Scholar