title: Anal canal development in the embryonic and early foetal period.
abstract: The aim of study is to investigate the development of the anal canal in human embryos and foetuses. In embryos at stage 19 the boundary between the ectodermal and endodermal linings of the anal canal is located just below the level of the internal anal sphincter muscle. Histological sections showed that the first signs of anal columns are observed in embryos at stage 21 (51 days).
mesh_terms: D001003:Anal Canal / Q000196:embryology* / Q000294:innervation / Q000502:physiology; D002988:Cloaca / Q000196:embryology / Q000502:physiology; D004475:Ectoderm / Q000166:cytology / Q000502:physiology; D004707:Endoderm / Q000166:cytology / Q000502:physiology; D005260:Female; D005333:Fetus / Q000196:embryology* / Q000502:physiology; D005836:Genitalia, Female / Q000002:abnormalities; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000196:embryology / Q000502:physiology; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology; D011262:Pregnancy Trimester, Second / Q000502:physiology