<synset id="n01465243" type="n">
<lex_filenum>05<lex_filenum/>
<word lex_id="2">yolk sac<word/>
<word lex_id="0">vitelline sac<word/>
<word lex_id="0">umbilical vesicle<word/>
<word lex_id="0">vesicula umbilicus<word/>
<pointer refs="n05515670">Hypernym<pointer/>
<def>membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional<def/>
<synset/>