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 ?
Well Centered: This yolk occupies center of egg and moves only slightly as the egg is turned
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The flabergasted couple and her son, Ryan, 20, watched in awe as the other four eggs from the same box hit the frying pan with double yolks.
It is best to use as an ingredient in baking or in any family dish that calls for a lighter yolk.
Although one must keep in mind that immunoperoxidase studies may have overlapping results with somatic carcinomas, use of a carefully selected panel to include markers of somatic carcinoma, markers of germ cell tumor (ie, SALL4), and more yolk sac-specific markers (ie, AFP and glypican 3) may be helpful.
Newly-appointed head of HR Rachel Thomas, who is working to develop Yolk Recruitment's longterm employee health and wellbeing policy, said: "Yolk's ethos is all about its people.
2004), pointed that the one of the crucial factors increasing the mortality of chickens in that period, point to the retention and infection of the yolk sac.
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.
You have to choose the best egg yolk for the moon cake.