Author: Glossary
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Oxaloacetic acid
A product of carbohydrate metabolism HOOC . CH2 . CO . COOH resulting from oxidation of malic acid during the Krebs cycle. May be derived from other sources.
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Oxalism
Poisoning from oxalic acid or an oxalate.
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Telolecithal ovum
An ovum in which the yolk is fairly abundant and tends to concentrate in one hemisphere.
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Primordial ovum
A germ cell that arises very early in the development of the embryo, usually in the yolk sac endoderm, migrates into the urogenital ridge, and is the precursor for the functional gamete.
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Meroblastic ovum
An ovum in which only the protoplasmic region undergoes cleavage, characteristic in ova containing a large amount of yolk.
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Mature ovum
A secondary oocyte that has completed its second meiotic division as a result of contact with a sperm. The nucleus of the mature ovum becomes the female pronucleus.
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Human ovum
The female gamete, required for reproduction. The ovum develops from an oogonium within the graafian follicle of the ovary and matures through the meiotic process of oogenesis. A mature ovum is about 0.13 to 0.14 mm (0.0051 to 0.0055 in) in diameter. At ovulation, the ovum is bounded by a translucent cellular membrane (the zona…
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Holoblastic ovum
An ovum that undergoes complete cleavage, as opposed to partial or meroblastic cleavage.
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Centrolecithal ovum
An ovum having a large central food yolk, as in a bird’s egg.
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Alecithal ovum
An ovum with a small yolk portion that is distributed throughout the protoplasm.