foregut

Short definition from Wiktionary

Noun

1. 1
   The anterior part of the alimentary canal of an embryo, from the mouth to the duodenum, in humans and some other animals.
2. 2
   The developed counterpart in the adult: the proximal part of the alimentary canal, which in humans runs from the mouth to the first half of the duodenum, up to the ampulla of Vater.