part of part of Homo sapiens muscle layer of oviduct isthmus of fallopian tube muscle layer of fallopian tube isthmus 2026-05-25T00:00:00Z FMA:18306 A muscular coat that is part of the isthmus of the fallopian tube, consisting of outer longitudinal and inner circular layers of smooth muscle that are responsible for peristaltic contractions propelling the ovum toward the uterus. Wikipedia:Fallopian_tube