Definition

1. Noun:
   • An embryonic membrane structure: The vitelline sac is a membranous structure present in the early embryos of mammals and other vertebrates.
   • A temporary circulatory system: It functions as the primary circulatory system in mammalian embryos, transporting nutrients, before the heart becomes fully functional and takes over this role.

Usage Examples

• Noun:
  • The vitelline sac is a critical structure for early embryonic development.
  • In the initial stages, the embryo relies on the vitelline sac for nutrient exchange.

Advanced Usage

• "yolk sac": This is a common synonym. In many biological and medical contexts, "vitelline sac" and "yolk sac" are used interchangeably, though "yolk sac" is more frequently used in general descriptions.
  • The doctor pointed to the yolk sac on the ultrasound monitor.

Variants and Related Words

• Yolk sac (n): The more common term for the vitelline sac, especially in general biology and medicine.
• Vitelline (adj): Pertaining to the yolk of an egg or to the vitelline sac.
  • The vitelline membrane surrounds the yolk.

Synonyms

• Yolk sac: The most direct and commonly used synonym.

Noun

1. membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional