yolk


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yolk

 [yōk]
the stored nutrient of the ovum.

yolk

(yōk, yōlk),
1. One of the types of nutritive material stored in the oocyte (ovum) for the nutrition of the embryo; yolk is particularly abundant and conspicuous in the eggs of birds. Synonym(s): vitellus
2. Fatty material found in the wool of sheep; when extracted and purified, it becomes lanolin.
[A.S. geolca; geolu, yellow]

yolk

(yōk) the stored nutrient of an oocyte or ovum.

yolk

(yōk)
n.
1.
a. The portion of the egg of egg-laying vertebrates, such as reptiles and birds, and of certain invertebrates that consists chiefly of protein and fat and serves as the primary source of nourishment for the early embryo.
b. This portion of the egg of a bird, especially a chicken, which is large, yellow, and surrounded by albumen.
2. A greasy substance found in unprocessed sheep's wool, which is refined to make lanolin.

yolk′y adj.

yolk

[yōk, yelk]
Etymology: AS, geolca
a material rich in fats and proteins that is contained in an ovum and that supplies nourishment to the developing embryo. The amount and distribution of the yolk within the ovum depend on the species of animal and the type of reproduction and development of offspring. In humans and most other mammals, yolk is absent or greatly diffused through the ovum. Mammalian embryos absorb nutrients directly from the mother through the placenta. Also called vitellus. See also deutoplasm.

yolk

(yōk)
1. One of the types of nutritive material stored in the oocyte for the nutrition of the embryo; particularly abundant and conspicuous in the eggs of birds.
Synonym(s): vitellus.
2. Fatty material found in the wool of sheep; when extracted and purified, it becomes lanolin.
[A.S. geolca;geolu, yellow]

yolk

the food store in the eggs of the majority of animals, made up mainly of fat and protein granules. It must contain all the essential ingredients for the entire development of the embryo. Where yolk is present in the egg, as in chickens, there is meroblastic CLEAVAGE, but where it is absent, or nearly so, cleavage is holoblastic, as in Amphioxus. Yolk is almost absent from mammal eggs, since food is provided directly from the mother, via the PLACENTA.

yolk

(yōk)
One of the types of nutritive material stored in the oocyte (ovum) for the nutrition of the embryo; particularly abundant and conspicuous in birds' eggs.
[A.S. geolca;geolu, yellow]

yolk

1. the stored nutrient of the ovum; it is also rich in antibody which is absorbed into the circulation of the embryo in the last third of incubation and is the mechanism by which maternal antibody is transferred to the young bird. See also yolk sac, egg.
2. the combined secretion of the sebaceous and sudoriferous glands of the sheep's skin and extractable from the fleece.

yolk sacculitis
see avian omphalitis.
yolk stalk
the connection, passing through the umbilicus, between the yolk sac and the fetus.
yolk stain
a stain of wool originating from the yolk.
References in periodicals archive ?
Yolk was established in 2009 by founding directors Dale Williams and Duncan Powell, and this year won the Sustainable Growth AwarA d at the Wales Fast Growth 50, recognising its appearance on the list for the third year in a row.
Yolk is at the start of a significant growth phase, creating 29 new positions over the coming 18 months to add to the existing team of 40, and will soon move to new premises in Cardiff.
Blue Cheese Deviled Eggs: Instead of mustard, stir in 1/2 cup crumbled blue cheese into the egg yolk mixture.
Yolk cholesterol level was performed by using 40 eggs (10 eggs from each group) collected in the last week of the study.
Diane Pogson said: "I recently bought my usual dozen eggs from Morrisons and five of them had double yolks.
He added: "Egg yolks contain all kinds of vitamins and minerals, and studies recently showed they contain more nutritional value - for example more vitamin B - than was previously thought.
We analyzed yolk mass variations in 212 eggs, belonging to 47 nests with a linear mixed model with a Gaussian family distribution and an identity-link function.
The egg yolk essentially acts as a binding element holding the coloured powders together," she says.
enteritidis is not often deposited inside the nutrient-rich yolks of naturally contaminated eggs, penetration by the bacteria through the vitelline membrane into the yolk could result in a rapid increase in bacterial levels.
The boffins hope egg yolks of rare birds could now be put in hen eggs to create life.
But as long as it's fresh, eating an egg with two yolks is perfectly fine.
Egg yolk played a role similar to cigarette smoking, according to the study by Western University, Canada, published in journal Atherosclerosis on Tuesday.