| 释义 |
vitelline sac
Thesaurus| Noun | 1. |  vitelline sac - membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functionalumbilical vesicle, vesicula umbilicus, yolk sacsac - a structure resembling a bag in an animal |
EncyclopediaSeeYolk Sacvitelline sac
yolk sac1. in vertebrates with telolecithal eggs, the highly vascular layer of splanchnopleure surrounding the yolk of an embryo; 2. in humans and other mammals, the sac of extraembryonic membrane that is located ventral to the embryonic disk and, after formation of the gut tube, is connected to the midgut; by the second month of development, this connection has become the narrow yolk stalk; the yolk sac is the first hematopoietic organ of the embryo, and its vitelline circulation plays an important role in the early embryonic circulation; the sac is also the site of origin of the primordial germ cells. Synonym(s): umbilical vesicle, vesicula umbilicalis, vitelline sacsacS00-828880 (sak) [L. saccus, sack, bag] A baglike part of an organ, a cavity or pouch, sometimes containing fluid. Synonym: saccus See: cystair sacIn a mammalian lung, an informal term for “pulmonary alveolus.” See: alveolus.allantoic sacThe expanded end of the allantois, well developed in birds and reptiles.alveolar sacPulmonary alveolus.amniotic sacThe inner fetal membrane that encloses the developing fetus and produces amniotic fluid. See: chorionchorionic sacThe outer fetal membrane that encloses the developing embryo.conjunctival sacThe cavity, lined with conjunctiva, that lies between the eyelids and the anterior surface of the eye.dental sacThe mesenchymal tissue surrounding a developing tooth.endolymphatic sacThe expanded distal end of the endolymphatic duct.heart sacThe pericardium.hernial sacIn the peritoneum, a saclike protrusion containing a herniated organ. See: herniaHilton's sac See: Hilton, Johnlacrimal sacThe upper dilated portion of the nasolacrimal duct situated in the groove of the lacrimal bone. The upper part is behind the internal tarsal ligament. It is 12 to 15 mm long. lesser peritoneal sacOmental bursa.peritoneal sacThe enclosed, transparent mesothelial sac that is squeezed between the abdominal wall and the abdominal viscera.vitelline sacYolk sac.yolk sacIn mammals, the embryonic membrane that is the site of formation of the first red blood cells and the cells that will become oogonia or spermatogonia. Synonym: vitelline sac See: embryo for illusvitelline sac
Related to vitelline sac: vitelline circulation, Vitelline vein, vitelline fistulaSynonyms for vitelline sacnoun membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functionalSynonyms- umbilical vesicle
- vesicula umbilicus
- yolk sac
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