Definition

1. Noun:
   • A thin, innermost membranous sac: The amnion is a thin, fluid-filled sac that surrounds and protects the developing embryo or fetus of higher vertebrates, including reptiles, birds, and mammals.

Usage

• The term "amnion" is a specialized biological and medical term. It is used to describe a specific anatomical structure during embryonic development.
• It is typically used in scientific, medical, and zoological contexts.

Examples

• Noun:
  • The amnion forms early in embryonic development.
  • The fluid within the amnion, called amniotic fluid, cushions the fetus.
  • In mammals, the amnion is a key component of the amniotic egg.

Advanced Usage

• "Amniotic": This is the related adjective form.
  • Amniotic fluid is crucial for fetal development.
• The condition of having an amnion defines the group "Amniota," which includes reptiles, birds, and mammals.

Variants and Related Words

• Amniotic (adj): Of or relating to the amnion or amniotic fluid.
  • The doctor performed an amniotic fluid test.
• Amniocentesis (n): A medical procedure involving the extraction of amniotic fluid for testing.
  • Amniocentesis can be used to check for genetic disorders.

Synonyms

• Amniotic sac: A common synonym, often used in medical contexts.
  • The ultrasound showed a healthy amniotic sac.

Notes

• The plural form is amnia or amnions.
• The amnion is a defining characteristic of amniotes, distinguishing them from amphibians and fish.

Noun

1. thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)