File:Quain's elements of anatomy (1882) (14761556804).jpg

Identifier: quainselementsofquai02 (find matches)
Title: Quain's elements of anatomy
Year: 1882 (1880s)
Authors: Quain, Jones, 1796-1865 Thomson, Allen, 1809-1884 Sharpey-Schäfer, E. A. (Edward Albert), Sir, 1850-1935, ed Thane, George Dancer, 1850-1930
Subjects: Human anatomy Anatomy
Publisher: New York : William Wood and co.
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

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Text Appearing Before Image:
WOLFFIANBODY OP THE CHICK DE-VELOPING THE PRONEPHROSAND GENITAL GLAND ON THE FOURTH DAT (from Balfourafter Waldeyer). m, mesentery; Z, body-wall;.a, portion of the epi-thelium from which the in-volution of the anterior partof the Miillerian duct s, istaking place ; a, thickenedgerminal epithelium in whichare seen primitive germinalcells, C and o ; E, modifiedmesoblast which will formthe stroma of the ovary;WK, Wolffian body ; y, Wolf-fian duct. toneal membrane, con-stituting the mesorchiumor mesovarium. Upperand lower bands fix theWolffian body; the upperpassing to the diaphragmmay be named the dia-phragmatic ; the lower, running down towards the groin from theWolffian duct, contains muscular fibres and constitutes the futuregubernaculum testis and round ligament of the uterus. In birds the distinction of sex is easily recognisable at an early periodby the occurrence in the female of an atrophy of the ovary and passageson the right side, Avliile those of the left are fully developed.
Text Appearing After Image:
THE TESTICLE Al^B THE OYAEY. 899 The Testicle.—In male liuman embryoes at the tenth week aheadyseminal canals are visible, being at first, according to Ivolliker, entirelycomposed of cells, but by the eleventh and twelfth weeks the tubes havebecome somewhat smaller, longer, and are now branched and possess amembrana propria. There is also by the end of the third month a com-mencement of lobular division, and the body of the testis is nowcovered with a condensed layer of fibrous tissue which forms the tunicaalbuginea. The serous covering is derived from the abdominal j)eri-toneum. The first origin of the glandular substance of the testis has not beenobserved in the human embryo, but fiom the observations of Egli inmale embiyo rabbits (No. 308) it appears that the epithelial cells, whichremain smaller than in the females, soon become connected with thedeeper blastema extending towards the Wolffian body, and form stringsof cells ruuuing into the body of the future testis. These are the

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