. An American text-book of obstetrics. For practitioners and students. Fig. 107.—Transverse section of sixteen day sheep embryo (Bonnet): ec, ectoderm; en, entoderm;pm, parietal mesoderm; vm, visceral mesoderm; am, amnion; ams, amniotic sac; s, s, somites; a, a,aorta; nc, notochord; n, neural canal; Hd, Wolffian duct; Wb, Wolffian body. Some days later, usually about the eighteenth day, the Wolffian bodiesappear as a series of short cylinders (Fig. 108) which form as buds from themesothelium of the body-cavity entirely independently of the development ofthe Wolffian duct. These rods of cells a
. An American text-book of obstetrics. For practitioners and students. Fig. 107.—Transverse section of sixteen day sheep embryo (Bonnet): ec, ectoderm; en, entoderm;pm, parietal mesoderm; vm, visceral mesoderm; am, amnion; ams, amniotic sac; s, s, somites; a, a,aorta; nc, notochord; n, neural canal; Hd, Wolffian duct; Wb, Wolffian body. Some days later, usually about the eighteenth day, the Wolffian bodiesappear as a series of short cylinders (Fig. 108) which form as buds from themesothelium of the body-cavity entirely independently of the development ofthe Wolffian duct. These rods of cells at first are solid; during the fourthweek they acquire lumina and become the Wolffian tubules, and later growtoward and join with the Wolffian ducts. The closed ends of the tubules IVd. Fig. 108.—Transverse section of seventeen day sheep embryo (Bonnet): am, amnion; as, amniotic sac;n, neural canal; s, somite differentiated into muscle-plate; lld. Wolffian duct; Wb, Wolffian body ; pm,parietal mesoderm; vm, visceral mesoderm ; a, a, fusing primitive aortae; i, intestine. become expanded and then invaginated by the apposition of blood-vessels sentinto the bodies from the aorta. The tufted blood-vessels and the invaginatedtubule constitute the Malpighian bodies of the Wolffian bodies, the predeces-sors of the similar structures of the permanent kidney. All parts of theWolffian bodies, therefore, are derived from the mesodermio tissues. Second-ary tubules are formed as outgrowths from the primary ones whose origin hasbeen sketched above. 120 AMERICAN TEXT-BOOK OF OBSTETRICS. The Wolffian bodies increase rapidly during the second month, gaining insize by the growth of the primary tubules and by the formation of new bodies act for a time as functionating excr
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
