nephridium
/nɪˈfrɪdɪəm
/noun (plural nephridia /nɪˈfrɪdɪə/) Zoology
(In many invertebrate animals) a tubule open to the exterior which acts as an organ of excretion or osmoregulation. It typically has ciliated or flagellated cells and absorptive walls.The organs they produce include segmental muscles, nephridia, gonads and gonoducts....
- Gametes are shed into the coelom and carried outside the body through the nephridia or as a result of the body wall actually rupturing.
- Torsion in gastropods has the unfortunate result that wastes are expelled from the gut and nephridia near the gills.
Derivatives
nephridial
- Nemerteans possess protonephridia consisting of multiciliated terminal cells, a ciliated nephridial duct and a nephridiopore opening at the epidermis.
- For example, Nielsen cites the nonsegmental nature of these cavities in nemerteans and the lack of associated metanephridia or otherwise open nephridial connections as evidence against homology.
- The whole layer of nephridial cytoplasm surrounding the radiating canals is 1 to 1.5 micron thick.
Origin
Late 19th century: modern Latin, from Greek nephrion (diminutive of nephros 'kidney') + the diminutive ending -idium.