yolk sac

noun Embryology.

an extraembryonic membrane that encloses the yolk of eggs in birds, reptiles, and marsupials and that circulates nourishment from the yolk to the developing embryo.

a similar membrane in placental mammals that encloses a mostly hollow space and loses its nutritive function entirely as the placenta develops.

Origin of yolk sac

First recorded in 1860–65

Words nearby yolk sac

Yokuts, Yolande, yoldring, yolk, yolk membrane, yolk sac, yolk-sac tumor, yolk stalk, YOLO, Yom Kippur, Yom Kippur War

Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for yolk sac

The yolk-sac is shown here simply as an irregular piece of tissue, the yolk having been removed.
Development of the Digestive Canal of the American Alligator|Albert M. Reese
The digestive system is advanced to a gut-tract, which is a straight tube connected with the yolk-sac.
The Ethics of Medical Homicide and Mutilation|Austin O'Malley
The epiblast spreads uniformly over the yolk-sac and not on the one side only as in the former eggs.
The Works of Francis Maitland Balfour, Volume 1|Francis Maitland Balfour
The duodenum extends only a short distance caudad to this point and then opens, aip, to the yolk-sac.
Development of the Digestive Canal of the American Alligator|Albert M. Reese

The cleft in his breast might close up now, and the last remnant of his yolk-sac vanish forever.
Forest Neighbors|William Davenport Hulbert

British Dictionary definitions for yolk sac

yolk sac

noun zoology

the membranous sac that is attached to the ventral surface of the embryos of birds, reptiles, and some fishes and contains yolk

the corresponding part in the embryo of mammals, which contains no yolk

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for yolk sac

yolk sac

n.

A membranous sac attached to an embryo, enclosing food yolk.umbilical vesicle

Scientific definitions for yolk sac

yolk sac

A sac that is attached to the gut of an embryo and encloses the yolk in bony fish, sharks, reptiles, mammals, and birds. In most mammals, the yolk sac functions as part of the embryo's circulatory system before the placenta develops.

单词	yolk sac
释义	yolk sac noun Embryology. an extraembryonic membrane that encloses the yolk of eggs in birds, reptiles, and marsupials and that circulates nourishment from the yolk to the developing embryo. a similar membrane in placental mammals that encloses a mostly hollow space and loses its nutritive function entirely as the placenta develops. Origin of yolk sac First recorded in 1860–65 Words nearby yolk sac Yokuts, Yolande, yoldring, yolk, yolk membrane, yolk sac, yolk-sac tumor, yolk stalk, YOLO, Yom Kippur, Yom Kippur War Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020 Example sentences from the Web for yolk sac The yolk-sac is shown here simply as an irregular piece of tissue, the yolk having been removed. Development of the Digestive Canal of the American Alligator\|Albert M. Reese The digestive system is advanced to a gut-tract, which is a straight tube connected with the yolk-sac. The Ethics of Medical Homicide and Mutilation\|Austin O'Malley The epiblast spreads uniformly over the yolk-sac and not on the one side only as in the former eggs. The Works of Francis Maitland Balfour, Volume 1\|Francis Maitland Balfour The duodenum extends only a short distance caudad to this point and then opens, aip, to the yolk-sac. Development of the Digestive Canal of the American Alligator\|Albert M. Reese The cleft in his breast might close up now, and the last remnant of his yolk-sac vanish forever. Forest Neighbors\|William Davenport Hulbert British Dictionary definitions for yolk sac yolk sac noun zoology the membranous sac that is attached to the ventral surface of the embryos of birds, reptiles, and some fishes and contains yolk the corresponding part in the embryo of mammals, which contains no yolk Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Medical definitions for yolk sac yolk sac n. A membranous sac attached to an embryo, enclosing food yolk.umbilical vesicle The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Scientific definitions for yolk sac yolk sac A sac that is attached to the gut of an embryo and encloses the yolk in bony fish, sharks, reptiles, mammals, and birds. In most mammals, the yolk sac functions as part of the embryo's circulatory system before the placenta develops. The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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