umbilical vesicle
Definition
Noun: 1. A membranous structure in mammalian embryos: The umbilical vesicle is an extraembryonic membrane. It functions as the primary circulatory system for the embryo, involved in nutrient absorption and blood cell formation, before the heart and definitive circulatory system become fully functional.
Usage
The term is used in technical, biological, and medical contexts to describe a specific, transient anatomical structure during early embryonic development. - The umbilical vesicle is a critical source of nutrients before the placenta is fully established. - In humans, the umbilical vesicle is also known as the yolk sac, though its role differs from that in birds and reptiles.
Advanced Usage
- Developmental Biology: The umbilical vesicle is a key structure studied in embryology, marking an early stage of vertebrate development.
- Comparative Anatomy: While present in all mammals, the size and functional significance of the umbilical vesicle can vary among species.
Variants and Related Words
- Yolk Sac: A common synonym, though in mammalian embryology, "umbilical vesicle" is the more precise term for the structure's specific function.
- Vitelline Sac: Another less common synonym.
- Extraembryonic Membrane: A broader category of structures that includes the umbilical vesicle, amnion, chorion, and allantois.
Synonyms
- Yolk Sac
- Vitelline Sac
Related Phrases / Terms
- Vesicle: A small sac or cyst containing fluid. The "umbilical vesicle" is a specific type of vesicle.
- Umbilical Cord: A different structure that connects the developing fetus to the placenta. It is not synonymous with the umbilical vesicle.
Noun
-
membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
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