. An American text-book of obstetrics. For practitioners and students. ceeds independently of menstruation. The ripe human ovum is a typical spherical cell, about millimeter indiameter, consisting of granular protoplasm or the vitellus, in which lies anucleus or germinal vesicle, about millimeter in diameter, containing awell-marked nucleolus, the germinal spot. The proper cell-wall is the vitellinemembrane, a structure of great delicacy, and often overlooked, outside of whichthe ovum is invested by the conspicuous zona pellucida (about millimeterthick), which must be regarded a
. An American text-book of obstetrics. For practitioners and students. ceeds independently of menstruation. The ripe human ovum is a typical spherical cell, about millimeter indiameter, consisting of granular protoplasm or the vitellus, in which lies anucleus or germinal vesicle, about millimeter in diameter, containing awell-marked nucleolus, the germinal spot. The proper cell-wall is the vitellinemembrane, a structure of great delicacy, and often overlooked, outside of whichthe ovum is invested by the conspicuous zona pellucida (about millimeterthick), which must be regarded as a secondary envelope contributed by thecells of the surrounding discus proligerus. The fully-developed Graafian follicle is ovoid, and consists of an externalinvestment of vascular connective tissue, the tunica fibrosa, which is lined bya thick layer of granular polyhedral epithelial cells, the membrana one point these cells are continued as a mass which immediately invests theovum and which is known as the discus proligerus. The interior of the well-. Fig. 61.—Section of well-developed Graafian follicle from human embryo (Von Herff); the enclosed ovum contains two nuclei. developed follicle (Fig. 61) contains a fluid, the liquor folliculi, separating theovum and its surrounding discus from the opposite wall of the sac. The mostprominent part of the ripe follicle is less vascular than those parts subjected toless pressure, one spot, the hilum follicidi, being free from blood-vessels, andcorresponding with the point at which the distended matured sac, from 2to 4 millimeters in diameter, finally ruptures. 72 AMERICAN TEXT-BOOK OF OBSTETRICS. 2. Menstruation.—At regular intervals throughout the childbearing periodthe lining of the uterus undergoes changes primarily designed to prepare afavorable resting-place for the product of conception. In the case of thenon-occurrence of pregnancy these changes terminate in the disintegration ofthe uterine mucous membrane an
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
