The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though yolk sac is far more widely used. In humans, the yolk sac is important in early embryonic blood supply,[1] and much of it is incorporated into the primordial gut during the fourth week of embryonic development.[2]
^Lutfey, Karen; Freese, Jeremy (2005). "Toward Some Fundamentals of Fundamental Causality: Socioeconomic Status and Health in the Routine Clinic Visit for Diabetes". American Journal of Sociology. 110 (5): 1326–1372. doi:10.1086/428914. ISSN 0002-9602. JSTOR 10.1086/428914. S2CID 17629087.
The yolksac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called...
outer side, the amniotic sac is connected to the yolksac, the allantois, and via the umbilical cord, the placenta. The yolksac, amnion, chorion, and allantois...
gestational sac is a portion of the conceptus consisting of a cavity between Heuser's membrane and the trophoblast. During formation of the primary yolksac, some...
between two fluid-filled cavities at either end: the primitive yolksac and the amniotic sac. The epiblast is adjacent to the trophoblast and made of columnar...
vitellointestinal duct, the yolk stalk, the omphaloenteric duct, or the omphalomesenteric duct, is a long narrow tube that joins the yolksac to the midgut lumen...
Among animals which produce eggs, the yolk (/ˈjoʊk/; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to...
yet capable of feeding themselves and carry a yolksac which provides stored nutrition. Before the yolksac completely disappears, the young fish must mature...
handle liquid waste. The allantois, along with the amnion, chorion, and yolksac (other extraembryonic membranes), identify humans and other mammals, birds...
envelope. The inner cell mass will give rise to the pre-embryo, the amnion, yolksac and allantois, while the fetal part of the placenta will form from the...
the trophoblast. When small, the sac cannot be distinguished from the early normal pregnancy, as there may be a yolksac, though a fetal pole is not seen...
chorion, allantois, and yolksac. The amnion and the chorion are the chorioamniotic membranes that make up the amniotic sac which surrounds and protects...
reptiles (amniotes). It develops from an outer fold on the surface of the yolksac, which lies outside the zona pellucida (in mammals), known as the vitelline...
the remains of the yolk in a yolksac which continues to nourish the larvae for a few days as they learn how to swim. Once the yolk is consumed, there...
become the amniotic sac that provides a protective environment for the developing embryo. The amnion, along with the chorion, the yolksac and the allantois...
Heikinheimo M (Dec 1999). "Transcription Factor GATA-4 Is Expressed in Pediatric YolkSac Tumors". American Journal of Pathology. 155 (6): 1823–9. doi:10...
Each primitive aorta anteriorly receives the vitelline vein from the yolk-sac, and is prolonged[clarification needed] backward on the lateral aspect...
The fetal pole is a thickening on the margin of the yolksac of a fetus during pregnancy. It is usually identified at six weeks with vaginal ultrasound...
extraembryonic membranes in birds, reptiles, and mammals: the yolksac which surrounds the yolk, the amnion which surrounds and cushions the embryo, the allantois...
bloodstream to the lungs. Yolksac tumors grow quickly and recur easily, and are not easily treatable once they have recurred. Stage I yolksac tumors are highly...
circulation, the bidirectional flow of blood between the yolksac and the embryo. The yolksac is the first extraembryonic structure to appear. This circulation...
for the presence of yolksac cells within the teratoma. These cells can develop into a frankly malignant tumor known as yolksac tumor or endodermal sinus...
stalk. Here, the gut tube maintains an attachment to the yolksac. The yolksac is a membranous sac attached to the embryo, which provides nutrients and functions...
malignancies. There are four main types of OGCTs, namely dysgerminomas, yolksac tumor, teratoma, and choriocarcinoma. Dygerminomas are Malignant germ cell...
chicken egg, with only a round yolksac A non-viable fertilized chicken egg, with a thin blood ring encircling the yolk A fertilized chicken egg, 11 days...
of development but without any transfer of nutrients to the young. The yolksac is the only source of nutrients for the developing embryo. There are at...
was found with an embryo inside it connected by an umbilical cord to a yolksac. The find confirmed the hypothesis that a sub-group of placoderms, called...
fish are called larvae. They are usually poorly formed, carry a large yolksac (for nourishment), and are very different in appearance from juvenile and...
hatched young of oviparous fish are planktonic larvae. They have a large yolksac and do not resemble juvenile or adult fish. The larval period in oviparous...
stalk. Here, the gut tube maintains an attachment to the yolksac. The yolksac is a membranous sac attached to the embryo, which provides nutrients and functions...
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