part of part of has part has part produces produces ependymal cell Vertebrata <vertebrates> SCO-spondin subcommissural organ http://upload.wikimedia.org/wikipedia/commons/d/d7/Gray715.png organum subcommissurale Occurs throughout the vertebartes [PMID:9579598, DOI:10.1002/ar.1091260210]. First appears in hagfish(Olsson). In many species, including the human, it reaches its full development during embryonic life[PMID:9579598]. During the course of phyletic evolution, one notes various changes. Indeed, in lower vertebrates, the SCO presents a greater degree of enzyme activity than the ependyma while in birds the ependyma demonstrates a more intense activity than the SCO[PMID:479574] Sometimes preceded by flexural organ[DOI:10.1007/BF00303086]. Hypendymal cells are rare in non-mammals [PMID:9579598]. Hypendymal cells being part of the subcommissural organ is not axiomatized as it is rare in non-mammals. Consider using GCIs if this axiom needs to be added. BTO:0001820 DHBA:12101 BAMS:SCO SCO GAID:794 CALOHA:TS-0986 FMA:72414 HBA:9489 UBERON:0002139 BIRNLEX:1028 DMBA:16514 MA:0002941 neuronames:483 corpus subcommissurale The subcommissural organ is a circumventricular organ consisting of ependymal and hypendymal cells which secrete SCO-spondin[WP,partially vetted]. MESH:D013351 Wikipedia:Subcommissural_organ dorsal subcommissural organ UMLS:C0038533 cerebral aqueduct subcommissural organ SCTID:369193006 TAO:0000683 ZFA:0000683 EMAPA:35828 midbrain tectum secretory circumventricular organ Reissner's fiber