1. Membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
   - yolk sac, vitelline sac, umbilical vesicle

Type of: sac

• embroilment
• embrown
• embryo
• embryogenic
• embryogeny
• embryologic
• embryologist
• embryology
• embryoma of the kidney
• embryonal
• embryonal carcinoma
• embryonal carcinosarcoma
• embryonal rhabdomyosarcoma
• embryonal rhabdosarcoma
• embryonic
• embryonic cell
• embryonic membrane
• embryonic stem-cell research
• embryonic tissue
• embryotic
• embus
• emcee
• EMDA
• eme
• emeer