Wharton’s jelly

https://doi.org/10.1351/goldbook.11379

Gelatinous substance that embeds the vessels of the umbilical cord.

Note: The jelly consists mainly of hydrated glycosaminoglycans such as hyaluronic acid and chondroitin sulfate.
Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 821 [Terms] [Paper]