Intermediate
Technical
In the Industry Vocabulary Test
chorion
Pronunciation: KOR-ee-on
The outermost fetal membrane that forms the fetal portion of the placenta.
Full Definition
The chorion is the outermost extraembryonic membrane surrounding the embryo and fetus. It develops into the fetal portion of the placenta and is responsible for gas and nutrient exchange. The chorion consists of an outer layer of trophoblast cells and an inner layer of mesoderm. In medical documentation, editors must distinguish between chorionic structures (relating to this membrane) and chronic conditions (long-term diseases).
Usage
Usage note: Often confused with 'chronic' in medical transcription. Ensure proper spelling when referring to chorionic structures.
In Context
- "Chorionic villus sampling was performed at 11 weeks gestation." — Prenatal diagnostic report
- "The chorion frondosum develops into the definitive placenta." — Embryology textbook
Also known as
chorionic membrane
Don't confuse with
chronic
chorioretinitis