amniotic sac (redirected from Birth sac)

sac (sak) a pouch or bag.

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air sacs  alveolar s's.

allantoic sac  the dilated portion of the allantois, becoming a part of the placenta in many mammals; it becomes the urachus in humans.

alveolar sacs  the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.

Alveolar sacs (sacculi alveolares).

amniotic sac  that formed by the amnion, containing the amniotic fluid.

chorionic sac  that formed by the vertebrate chorion, surrounding the embryo, amniotic cavity, and amniotic sac and contributing to the fetal part of the placenta.

conjunctival sac  the potential space, lined by conjunctiva, between the eyelids and eyeball.

dental sac  the dense fibrous layer of mesenchyme surrounding the enamel organ and dental papilla.

endolymphatic sac  the blind, flattened cerebral end of the endolymphatic duct.

gestational sac  that comprising the extraembryonic membranes that envelop the embryo or fetus; in humans, that formed by the fused amnion and chorion.

heart sac  pericardium.

hernial sac  the peritoneal pouch enclosing a hernia.

Hilton's sac  laryngeal saccule.

lacrimal sac  the dilated upper end of the nasolacrimal duct.

yolk sac  the extraembryonic membrane that connects with the midgut; at the end of the fourth week of development it expands into a pear-shaped vesicle (umbilical vesicle) connected to the body of the embryo by a long narrow tube (yolk stalk) . In mammals, it produces a complete vitelline circulation in the early embryo and then undergoes regression.

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amniotic sac

n.

See amnion.

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Amniotic sac

The membranous sac that surrounds the embryo and fills with watery fluid as pregnancy advances.

Mentioned in: Childbirth

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amniotic sac,

a thin-walled bag that contains the fetus and amniotic fluid during pregnancy. It has a capacity of 4 to 5 L at term. The wall of the sac extends from the margin of the placenta. The amnion, chorion, and decidua that make up the wall are each a few cell layers thick. They are closely applied-though not fused-to one another and to the wall of the uterus. The intact sac and its fluid provide for the equilibration of hydrostatic pressure within the uterus. During labor, the sac effects the uniform transmission of the force of uterine contractions to the cervix for dilation.

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amniotic sac,

n a thin membrane that completely surrounds the embryo and contains a protective fluid in which the embryo is immersed. Also called the
amnion.

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amniotic

pertaining to the amnion.

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amniotic fluid

the albuminous fluid contained in the amniotic sac.

amniotic plaque

small, 2 to 4 mm diameter, poxlike lesion on the inside of the amnion. Constant on the bovine amnion during the middle trimester and causes no problems nor has any known function.

amniotic sac

the amnion; the sac enclosing the fetus suspended in the amniotic fluid.

amniotic vesicle

see amniotic sac (above). Palpation of the vesicle per rectum in the cow is a common test for pregnancy between the 35th and 65th day of pregnancy.

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amniotic sac

amnion, bag of waters, membranes Obstetrics An amniotic fluid-filled thin membraned sac which surrounds the embryo of amniote vertebrates, and provides a fluid cushion, prevents dehydration, acting as a waste receptacle during embryonic development. See Amnion.

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Patient discussion about Birth sac.

Q. what does it mean when an ultrasound shows an empty amniotic sac and no baby?

A. This exact thing happened with my friend who is now 22 weeks with her first baby. She had 2 additional sacs - both empty - and the doctor said that the pregnancy had probably started out as triplets but that only one of the embryos had actually established and continued to grow.

Her doctor said it is very common for a woman to have more than one egg fertilize but that in most cases the pregnancy continues as a singleton only. She told my friend that the empty sacs would just disappear through time (which they did) and that they posed no danger to her baby.