ovum (o'vum)

The large nucleated cell formed in the generative organs which is capable of development into an organism similar to the parent. In its young stage it is a typical cell, consisting of a ma of naked protoplasm containing a nucleus and a nucleolus; at a more advanced stage of development (a) an inclosing membrane or membranes (the vitelline membrane, the zona pellucid a, and in some cases a shell), (b) the vitellus, (c) the nucleus (germinal vesicle), and (d) the nucleolus (germinal spot). ■ The human o. is about Vs mm. in diameter, and, as with the ova of higher animals generally, is produced only by the female and must be fertilized by union with a spermatozoid before it is. capable o£ developing into an organism like its parent, alb or ovi, albumen ovi, al- Dumor ovi. White of egg. ovi albumen, ovi albumen tum, ovi alb us liquor, ovi candidum. White of egg. primitive o. i. One of the large clear cells in the germinal epithelium which usually collect into groups and sink into the ovarian stroma, where some become transformed into ova, others into follicular epithelium. 2. One of the primitive sexual cells, testae ovorum preparatae. Eggshells, especially shells of hen's eggs, powdered and freed from impurities by agitation with water. [Lat., from Gr., oon, egg.]