3rd week Intermediate Nephrogenic Urogenital cord ridge mesoderm Mesonephric Urinary system, ridge Genital excurrent ducts Gonadial → Gonad ridge PudendumIntermediate mesoderm Intermediate mesoderm ─────→ Nephrogenic cord ───→ Urogenital ridge 3rd week ─── Mesonephric ridge Gonadial ridge Urinary system, Genital excurrent ducts Gonad Pudendum