| slovo | definícia |
yolk sac
(encz) | yolk sac, n: |
yolk sac
(wn) | yolk sac
n 1: membranous structure that functions as the circulatory
system in mammalian embryos until the heart becomes
functional [syn: yolk sac, vitelline sac, {umbilical
vesicle}, vesicula umbilicus]
2: membranous structure enclosing the yolk of eggs in birds,
reptiles, marsupials, and some fishes; circulates nutrients
to the developing embryo |
| | podobné slovo | definícia |
Yolk sack
(gcide) | Yolk \Yolk\ (y[=o]lk or y[=o]k; 277), n. [OE. yolke, yelke,
[yogh]olke, [yogh]elke, AS. geoloca, geoleca, fr. geolu
yellow. See Yellow.] [Written also yelk.]
[1913 Webster]
1. The yellow part of an egg; the vitellus.
[1913 Webster]
2. (Zool.) An oily secretion which naturally covers the wool
of sheep.
[1913 Webster]
Yolk cord (Zool.), a slender cord or duct which connects
the yolk glands with the egg chambers in certain insects,
as in the aphids.
Yolk gland (Zool.), a special organ which secretes the yolk
of the eggs in many turbellarians, and in some other
invertebrates. See Illust. of Hermaphrodite in Appendix.
Yolk sack (Anat.), the umbilical vesicle. See under
Unbilical.
[1913 Webster] |
|