A manual of obstetrics . the placenta is fully formed and is ableto assume the functions for which it is destined. Thesefimctions diVC the supplying of nourishment from the motherto the fetus, the oxygenation of the impure fetal blood, andthe excretion of the effete products from the fetus. It isprobable that the placenta also possesses to a certain extenta glycogenic function. Any disturbance of these functionswill result in disease or death of the fetus. The Placenta atTerm.—When fully developed the placenta is a flat, circular,spongy structure from 15 to 23 cm. ( to in.)in diam
A manual of obstetrics . the placenta is fully formed and is ableto assume the functions for which it is destined. Thesefimctions diVC the supplying of nourishment from the motherto the fetus, the oxygenation of the impure fetal blood, andthe excretion of the effete products from the fetus. It isprobable that the placenta also possesses to a certain extenta glycogenic function. Any disturbance of these functionswill result in disease or death of the fetus. The Placenta atTerm.—When fully developed the placenta is a flat, circular,spongy structure from 15 to 23 cm. ( to in.)in diameter, \y^ to 2yi cm. ( to in.) thickat the central point, and weighing usually slightly over a PREGNANCY OR GESTATION. 57 pound. It presents two surfaces—a smooth internal orfetal surface, clothed with the fetal membranes, and to thecenter of which is generally attached the umbilical cord;and a dark-red, granular, lobulated external or maternalsurface, by which it is attached to the decidua. Its usual. Fig. 30.—Human placenta, fetal surface. The amnion is dissected off one side to show thevessels (Tarnier). point of attachment is the upper posterior uterine wall nearone or the other tubal orifice, and it generally faces theventral surface of the fetus. It is possible, however, for itto be attached to any portion of the surface of the uterinecavity. In structure it is both fetal and maternal, thoughmainly the former; it is composed of from fifteen to twentytufts of chorionic villi, together with the immensely hj^per-trophied connective tissue of the uterine mucosa {clecidnascrotina). Ultimate Disposal.—Shortly before the termina-tion of pregnancy a partial fatty degeneration occurs in thematernal portion of the placenta; in this way the separationof the organ at parturition is facilitated. Should this processbe carried too far, fetal death may result from asphyxiation, 58 A MANUAL OF OBSTETRICS. either from premature separation of the placenta or frominte
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
