File:Hand-book of physiology (1856) (14750350256).jpg

Identifier: handbookofphysio1856kirk (find matches)
Title: Hand-book of physiology
Year: 1856 (1850s)
Authors: Kirkes, William Senhouse, 1823-1864
Subjects: Physiology Human physiology
Publisher: London : Walton and Maberly
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
e chorion consist at firstentirely of cells bounded by an external layer of texturelessmembrane, which gives their form (Goodsir).. When the ovum,with its villous chorion, reaches the uterus, the villi becomeimbedded in the secretion pouied forth by the enlarged foUi-cular glands of the mucous membrane of that organ; and fromthis they doubtless derive the nutriment on which the embryoat first subsists. Further provision is, however, shortly made for procuringnourishment, by the development of blood-vessels within thevilli, and the junction of these with the branches of the um- THE EMBRYO IN THE UTERUS. 677 bilical vessels brought by the allantois to the chorion. Thefoetal vessels thus come into intimate relation with the vesselsof the uterus. The part at which this relation between thevessels of the foetus and those of the parent ensues is not, how-ever, over the whole surface of the chorion; for, although allthe villi become vascular, yet, in the human subject, it is at one Fig. 87.*
Text Appearing After Image:
* Fig. 87 represents a perpendicular section of a uterus, with a fullyformed ovum. A plug of lymph (1) occupies the cervix uteri; 2, indi-cates the opening of the Fallopian tube on one side; 3, the decidua vera; 678 VILLI OF THE CHORION. part only that tliey are greatly developed, and by their branch-ins: 2:ive rise, with the vessels of the uterus, to the formationof the jilacenta (fig. 87). The ovum appears to have a firm connection with the uterusin all Mammalia, with the exception of the )Marsupiaha andMonotremata. The means of attachment are always eithervascular vilh or folds of the chorion. The chorion receivesits blood-vessels from the umbilical vessels of the foetus, whichare distributed upon the allantois, and by it are conducted tothe chorion. The villi are sometimes distributed over thewhole surface of the chorion; sometimes they form a zonearound the ovum; at other times they are collected into severalmasses, or cotyledons, scattered over the chorion; and lastly,in man and

Note About Images