File:An American text-book of physiology (1897) (14783009582).jpg

Identifier: americantextbook00howe (find matches)
Title: An American text-book of physiology
Year: 1897 (1890s)
Authors: Howell, William H. (William Henry), 1860-1945 Bowditch, H. P. (Henry Pickering), 1840-1911
Subjects: Physiology
Publisher: Philadelphia : Saunders
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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oped in the interior within cavities called, from their discoverer,Graafian follicks(G.f), from primitive ova that are modified cells of the germinalepithelium of the embryo. It has been calculated that the two human ovariesat the age of eighteen years contain an average of 72,000 primitive ova, butthat not more than four hundred of these arrive at maturity. Each Graafianfi)llicle is lined by an ei)ithelial layer several cells thick, the membravagranulosa, and is filled with clear viscid fluid, the liquor follmiU, which con-tains albuminoid matter. Imbedded in the epithelium upon one side isusually a single ovum, completely surrounded by the cells and forming aprominent hillock which projects well into the cavity of the follicle. The BEPROD UCTION. 893 epitluIiuni iiuinodiatcly surroimdintr the ovum is the discus prolicjerus. Withinthe discus the ovum grows and becomes surrounded by tl»e zona pellucida. Inthe process of growth the (Jraafian loUide approaches the surface of the ovary,
Text Appearing After Image:
Fig. 309.—Diagram of the female reproductive organs (modified from Henle and Symington): o, ovary ;O.f, Graafian follicle containing an ovum; c.l, corpus luteum; p, parovarium; /, fimbriated end of F. t,Fallopian tube; u, body, and c, cervix of uterus; o e, os uteri externum; vg, vagina; h, hymen; u, open-ing of urethra; v, vulval cleft; n, labia minora, or nymphiE; l.m, labia majora. and finally comes to form a minute rounded vesicular projection covered onlyby the ovarian epithelium. When fully ready for discharge, the wall of thefollicle becomes ruptured, probably by the increasing pressure of the containedliquid, and the ovum with its zona pellucida and a portion or all of the discusproUyerus, now called the corona radiata, is cast out upon the surface of theovary to be taken up by the Fallopian tube. The empty follicle undergoeschanges and becomes the corpus luteum (cl). Usually the corpus luteum de-generates within a few days and ultimately disappears. If, however, pregnancyfo

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