amnion definition

  • noun:
    • A thin, hard, membranous sac that encloses the embryo or fetus of a mammal, bird, or reptile. Its filled up with a serous fluid when the embryo is suspended.
    • the innermost membrane layer of this fetal membranes of reptiles, birds, and mammals; the sac when the embryo is suspended.
    • A thin membrane layer surrounding the embryos of animals, birds, and reptiles.
    • In physiology and vertebrate zoöl., one of the fetal appendages; the innermost one of the membranes which envelop the embryo associated with greater vertebrates, as mammals, wild birds, and reptiles; the liner membrane layer of a shut sac, familiarly labeled as the “bag of waters,” where fetus is contained.
    • In entomology, a membrane which encompasses the larva of many bugs, once the millepeds (Iulidæ), for some time after they tend to be batched from the egg. It really is regarded by some once the analogue of the amnion of a vertebrate.
    • A reflected part of a membrane, in ascidians, which lines the inner wall surface regarding the ovisac, and kinds some sort of amniotic financial investment regarding the embryo.
    • In botany, a name formerly directed at the fluid items for the embryo sac.
    • often mistakenly written amnios.
    • In echinoderms, the sac inside pluteus larva inclosing the developing echinus.
    • slim innermost membranous sac enclosing the establishing embryo of greater vertebrates (reptiles, birds and animals)

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