Source:http://linkedlifedata.com/resource/umls/id/C0017472
MSH: The three primary germinal layers (ECTODERM; ENDODERM; and MESODERM) developed during GASTRULATION that provide tissues and body plan of a mature organism. They derive from two early layers, hypoblast and epiblast.,CSP: one of the three layers of primodial cells comprising the early embryo, formed during gastrulation.