RT Journal Article
T1 Topographical relationships of the yolk sac remnant and vitelline vessels with the midgut loop in the extra-embryonic coelom of human embryos
A1 Jin, Zhe-Wu
A1 Kim, Ji Hyun
A1 Yamamoto, Masahito
A1 Murakami, Gen
A1 Abe, Shinichi
A1 Rodríguez Vázquez, José Francisco
AB The yolk sac is supplied by the vitelline artery and vein (VA, VV), which run through the yolk stalk in combination with the omphaloenteric duct. Moreover, the VV takes a free posterior course outside the midgut mesentery containing the secondarily-developed superior mesenteric vein (SMV). However, the regression process of these structures has not been demonstrated photographically. The present study evaluated serial histological sections from 20 embryos of stages 15–19 or crown-rump length (CRL) 7.5–20 mm. All specimens carried the SMV as sequential tissue slits. However, an omphaloenteric duct with epithelia continuous with the midgut loop was not observed. In smaller embryos (CRL <13 mm) the VA extended distally or anteriorly from the midgut apex in the extra-embryonic coelom, whereas in larger embryos (CRL 16–20 mm) the artery was absent from the distal side of the apex. The entire course or part of the VV outside the mesentery was always seen, but four larger embryos lacked the venous terminal near the duodenum. A vacuole-like remnant of the yolk sac was present in all smaller embryos (CRL <10 mm), but was absent from 7 of the 11 larger embryos. The size of the remnant was equal to the thickness of the VA or VV, with the remnant being sandwiched between the VA and VV. Moreover, the regressing yolk sac often communicated with or opened to the VV. Consequently, the yolk sac regressed first, followed by the regression of the VA until 6 weeks. The yolk stalk was clearly observed until 5 weeks.
PB Korean Association of Anatomists
SN 2093-3665
YR 2022
FD 2022-09-30
LK https://hdl.handle.net/20.500.14352/109045
UL https://hdl.handle.net/20.500.14352/109045
LA eng
NO Wuxi Municipal Bureau on Science and Technology (China)
NO Zhangjiagang Science and Technology Innovation Project (China)
DS Docta Complutense
RD 6 abr 2025