Centrolecithal Ovum

centrolecithal ovum

[¦sen·tro′les·ə·thəl ′ō·vəm] (cell and molecular biology) An egg cell having the yolk centrally located; occurs in arthropods.

Centrolecithal Ovum

a female reproductive cell, or ovum, whose cytoplasm contains a large quantity of centrally located yolk. Cytoplasm containing no yolk is found mainly on the surface of the ovum; only a small portion of cytoplasm occurs in the center of the ovum, where the nucleus is located. The central portion of the cytoplasm is connected to the peripheral layer of cytoplasm by delicate strands that pass through the yolk layer. Centrolecithal ova are characteristic of many arthropods, in particular, insects. When a centrolecithal ovum undergoes cleavage, the nucleus divides many times. The resulting nuclei migrate along the cytoplasmatic strands to the surface of the ovum, where cells form around them. This cleavage is called superficial.

centrolecithal ovum

ovum

[o´vum] (pl. o´va) (L.) the female reproductive or germ cell which after fertilization is capable of developing into a new member of the same species; called also egg. The term is sometimes applied to any stage of the fertilized germ cell during cleavage and even until hatching or birth of the new individual. The human ovum consists of protoplasm that contains some yolk, enclosed by a cell wall consisting of two layers, an outer one (zona pellucida) and an inner, thin one (membrane" >vitelline membrane). There is a large nucleus (germinal vesicle) within which is a nucleolus (germinal spot). adj., adj o´vular.

Ovum.centrolecithal ovum one with the yolk concentrated at the center of the egg, surrounded by a peripheral shell of cytoplasm, and with an island of cytoplasm surrounding the nucleus, such as that of an arthropod.holoblastic ovum one that undergoes total cleavage.isolecithal ovum one with a small amount of yolk evenly distributed throughout the cytoplasm.meroblastic ovum one that undergoes partial cleavage.primitive ovum (primordial ovum) any oocyte very early in its development.telolecithal ovum one with a comparatively large amount of yolk massed at one pole, such as that of a reptile or bird.

cen·tro·lec·i·thal o·vum

one in which the yolk is mostly located near the center of the egg, as in arthropods.

centrolecithal ovum

An ovum having a large central food yolk, as in a bird's egg.See also: ovum

单词	centrolecithal ovum
释义	DictionarySeeovum Centrolecithal Ovum centrolecithal ovum [¦sen·tro′les·ə·thəl ′ō·vəm] (cell and molecular biology) An egg cell having the yolk centrally located; occurs in arthropods. Centrolecithal Ovum a female reproductive cell, or ovum, whose cytoplasm contains a large quantity of centrally located yolk. Cytoplasm containing no yolk is found mainly on the surface of the ovum; only a small portion of cytoplasm occurs in the center of the ovum, where the nucleus is located. The central portion of the cytoplasm is connected to the peripheral layer of cytoplasm by delicate strands that pass through the yolk layer. Centrolecithal ova are characteristic of many arthropods, in particular, insects. When a centrolecithal ovum undergoes cleavage, the nucleus divides many times. The resulting nuclei migrate along the cytoplasmatic strands to the surface of the ovum, where cells form around them. This cleavage is called superficial. centrolecithal ovum ovum [o´vum] (pl. o´va) (L.) the female reproductive or germ cell which after fertilization is capable of developing into a new member of the same species; called also egg. The term is sometimes applied to any stage of the fertilized germ cell during cleavage and even until hatching or birth of the new individual. The human ovum consists of protoplasm that contains some yolk, enclosed by a cell wall consisting of two layers, an outer one (zona pellucida) and an inner, thin one (membrane" >vitelline membrane). There is a large nucleus (germinal vesicle) within which is a nucleolus (germinal spot). adj., adj o´vular.Ovum.centrolecithal ovum one with the yolk concentrated at the center of the egg, surrounded by a peripheral shell of cytoplasm, and with an island of cytoplasm surrounding the nucleus, such as that of an arthropod.holoblastic ovum one that undergoes total cleavage.isolecithal ovum one with a small amount of yolk evenly distributed throughout the cytoplasm.meroblastic ovum one that undergoes partial cleavage.primitive ovum (primordial ovum) any oocyte very early in its development.telolecithal ovum one with a comparatively large amount of yolk massed at one pole, such as that of a reptile or bird. cen·tro·lec·i·thal o·vum one in which the yolk is mostly located near the center of the egg, as in arthropods. centrolecithal ovum An ovum having a large central food yolk, as in a bird's egg.See also: ovum
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