Yolk Sac Definition

noun
A saclike vascular membrane containing yolk, an outgrowth from the ventral surface of very yolky vertebrate embryos, as those of fishes, birds, or reptiles, that supplies nourishment to the embryo.
Webster's New World
A homologous organ in most mammalian embryos that contains no yolk and that becomes a vestige at an early embryonic stage.
Webster's New World
Synonyms:
  • vesicula umbilicus
  • umbilical vesicle
  • vitelline sac

Other Word Forms of Yolk Sac

Noun

Singular:
yolk sac
Plural:
yolk sacs

Yolk Sac Sentence Examples

  • But in a few European and North American species, and in a great many inhabitants of the tropics, the egg is large and a considerable portion of it persists for a long time as a yolk-sac. Although the segmentation is always complete, it is very irregular in these types, some of which make a distinct approach to the meroblastic egg.

  • Expansion of the extra-embryonic coelom cavity allows the yolk sac and allantois to expand into the coelom cavity allows the yolk sac and allantois to expand into the coelom cavity from the gut of the embryo.

  • Does the human fetus temporarily develop gills, a tail, and a yolk sac?

  • Is yolk sac size in hatching fishes a good indicator of how long a fish can survive without food?

  • Often young birds acquire the infections from the hen or through navel or yolk sac infections.

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Words Starting With

YYOYOL

Words Ending With

CACSAC

Unscrambles

yolk sac

Words Starting With Y and Ending With C

Starts With Y & Ends With CStarts With YO & Ends With CStarts With Y & Ends With AC

Word Length

8 Letter Words8 Letter Words Starting With Y8 Letter Words Ending With C