Definition

Noun: - A microscopic, finger-like projection: A chorionic villus is one of the numerous tiny, vascular projections that extend from the chorion (the outermost fetal membrane) of the developing embryo. - A functional unit of the placenta: These villi interlock with the mother's uterine tissue (decidua basalis) to form the placenta, facilitating the critical exchange of nutrients, gases, and waste between the maternal and fetal bloodstreams.

Usage

• Scientific/Medical Context: The term is used almost exclusively in embryology, obstetrics, and prenatal medicine to describe the anatomical structures essential for pregnancy.
  • The doctor explained that the placenta is formed from both maternal tissue and fetal chorionic villi.
  • A chorionic villus sampling (CVS) is a prenatal test that involves taking a small sample of these villi for genetic analysis.

Advanced Usage

• Chorionic Villus Sampling (CVS): This is a standard compound term in prenatal diagnostics. It refers to a procedure typically performed between 10-13 weeks of pregnancy to obtain cells from the chorionic villi to test for chromosomal abnormalities and other genetic disorders.
  • They opted for chorionic villus sampling to get early information about the baby's genetic health.

Variants and Related Words

• Chorion (noun): The outermost extraembryonic membrane surrounding the embryo of reptiles, birds, and mammals. The chorionic villi grow from this membrane.
• Villus (noun, singular): A general term for a small, slender, vascular projection. The plural is villi. Chorionic villi are a specific type.
• Placenta (noun): The organ that develops during pregnancy, formed by the interlocking of chorionic villi and maternal uterine tissue.

Synonyms

• Placental villus: A less common but accurate synonym, emphasizing its role in the placenta.
• Fetal villus: Highlights its origin from the fetus.

Notes on Meaning

This term has a single, highly specific meaning in biological and medical contexts. It does not have idiomatic or figurative uses. Its primary function is descriptive of a key structure in mammalian reproduction.

Noun

1. one of the tiny villi that stick out of the fetal chorion and combine with the mother's uterine tissue to form the placenta