AMNION Meaning and
Definition
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The amnion is a vital fetal membrane that surrounds and protects the developing embryo within the uterus during pregnancy. It is one of the extraembryonic membranes, derived from the innermost layer of cells in the embryonic disc, called the ectoderm. The amnion forms early in embryonic development around day 8 and grows to enclose the entire embryo.
This membranous sac is filled with a clear amniotic fluid rich in nutrients, electrolytes, and antibodies, acting as a cushion to absorb shocks, regulate temperature, and provide buoyancy for the growing fetus. It also aids in preventing dehydration, enabling proper growth and development.
The amnion plays a crucial role in protecting the embryo from physical trauma, bacterial infections, and maintaining an optimal environment for development. It functions as a selective barrier, allowing the exchange of gases (such as oxygen and carbon dioxide) and waste products between the developing fetus and the maternal bloodstream, facilitated by the chorion. Additionally, it aids in the structural support of the umbilical cord, which connects the embryo to the placenta for nutrient and waste exchange.
During childbirth, the amnion ruptures, known as the "breaking of the water," releasing the amniotic fluid, which indicates that labor is imminent. The amnion is expelled after the birth of the baby as part of the placenta.
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The inner of the membranes composing the sac, bag of waters, which envelops the fetus in the uterus. It consists of two layers, an inner or epiblastic, the true amnion, and an outer or mesoblastic, the false amnion. The latter, which is in contact with the chorion, either unites with that or disappears. The sac lined by the amnion contains the liquor amnii in which the fetus floats.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
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In anat., the inner membrane covering the foetus; in bot., the covering of the embryo of the seed.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
Common Misspellings for AMNION
Etymology of AMNION
The word "amnion" comes from the Greek word "amnion", which means "lamb's membrane" or "bowl". It is derived from the Greek word "amnos", meaning "lamb". This term was used because the innermost membrane surrounding the fetus during development, called the amnion, resembles a thin sac or a little bowl.
Similar spelling words for AMNION
- amino,
- Ammon,
- Aman,
- amenia,
- amman,
- ammonia,
- amine,
- amini,
- amain,
- anion,
- amann,
- amon,
- ammine,
- amen,
- ammino,
- Amin,
- Amina,
- amano.
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