File:Cunningham's Text-book of anatomy (1914) (20817752025).jpg

Title: Cunningham's Text-book of anatomy
Identifier: cunninghamstextb00cunn (find matches)
Year: 1914 (1910s)
Authors: Cunningham, D. J. (Daniel John), 1850-1909; Robinson, Arthur, b. 1862, ed
Subjects: Anatomy
Publisher: New York, W. Wood
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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DEVELOPMENT OF THE UEINO-GENITAL OEGANS. 1335 deferens from the more caudal portion. The ductuli aberrantes and the rudimentary tubules of the paradidymis are to be looked upon as persistent tubules, of a more caudal portion of the Wolffian body, which have failed to become connected with the tubules of the testis. The seminal vesicles are developed in the third month as evaginations which arise from the Wolffian ducts, near their caudal extremities. Each at first has the appearance of a longitudinal groove in the wall of the ductus deferens, which closes over and becomes cut off from the main tube except at the point where later on the duct of the seminal vesicle joins the ductus deferens. The Mtillerian ducts atrophy in the male embryo, but the appendices of the testis are vestigial remains of their cephalic portions, while the utriculus prostaticus represents the caudal fused portions which, in the embryo, occupy the genital cord. Ducts in the Female.—The Mtillerian ducts in the female retain their openings into the body cavity, and their anterior portions become the uterine tubes. Their fused posterior parts, which at first join the urino-genital canal, give rise to the uterus and vagina. The manner in which the original position of the opening of the Mtillerian ducts becomes shifted, by the formation of a new passage or by the shortening of the urino- genital canal, has already been mentioned (p. 1333). The final position of the opening is in the urino-genital cleft of the adult. The vaginal portion of the fused Mtillerian ducts is at first relatively very short, and at the point where it opens into the urino-genital canal a slight fold appears, which is the future hymen. The vagina increases rapidly in length as its opening- moves downwards towards the urino-genital cleft. In the human embryo during the third month the closely applied Mtillerian ducts, which higher up have fused to form the uterus, are represented at their inferior ends by a pair of rapidly elongating solid cellular cords, which at a later stage break down to form the vagina. The Wolffian ducts and the mesonephros atrophy in the female, but traces of them are to be found in the ep-oophoron and par-ooph- oron of the adult. In the foetus the Wolffian duct can be traced along the side of the uterus as far as the upper end of the vagina. Prostate.—The glandular portion of the prostate arises as a series of solid out- growths from the epithelium of the urino- genital canal during the third month. The outgrowths, which are at first simple, be- come branched and finally acquire a lumen. They are arranged in three groups—an upper and a lower dorsal, and a ventral group. The glands of the ventral group soon became reduced in number and often completely disappear; those of the upper dorsal group form the chief part of the gland. The prostatic glands arise in both sexes, but in the female, where they are known as para-urethral glands, they are few in number and not densely packed as in the male. The muscular tissue of the prostate is derived from the muscular wall of the urethra. The bulbo-lirethral glands arise in the third month, and appear to be developed from the epithelium of the urino-genital canal. The larger vestibular glands in the female arise as epithelial outgrowths in the same manner as the bulbo-urethral glands.
Text Appearing After Image:
Fig. 1047.—The Uri^o-genital Passages in the Female. Derivations of the Mtillerian duct, orange. Ureter, green solid outline. The ep-oophoron is indicated in green near the opening of Mulleriau duct and near the ovary. External Gexital Oegaxs. The external genital organs are developed in the region of the ectodermal cloacal fossa, and those of the male and female cannot be distinguished from one another in the earlier stages. The fossa at first extends on the ventral aspect of the body almost

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