extraembryonic coelom การใช้

• Mammalian embryos develop two cavities : the intraembryonic coelom and the extraembryonic coelom ( or chorionic cavity ).
• As development progresses, small lacunae begin to form within the extraembryonic mesoderm which enlarge to become the extraembryonic coelom.
• The intraembryonic coelom is lined by somatic and splanchnic lateral plate mesoderm, while the extraembryonic coelom is lined by extraembryonic mesoderm.
• The extraembryonic coelom divides the extraembryonic mesoderm into two layers : extraembryonic splanchnopleuric mesoderm, which lies adjacent to Heuser's membrane around the outside of the primitive yolk sac, and extraembryonic somatopleuric mesoderm, which lies adjacent to the cytotrophoblast layer of the embryo.