The laws and mechanics of circulation, with the principle involved in animal movement . Fig. 134 —Impregnated Uterus, showing connection between villosities of chorion anddecidual membranes.—Dalton. ing ends of the growing tufts, which readily find their way intothe lumen of the expanded uterine tubules (Fig. 134), rapidlygrowing and branching in the follicular cavities, which increase 324 PHYSIOLOGICAL ANATOMY. correspondingly, the two growing pari passu with each other,the branched processes constituting the villi of the chorion(Fig. 135); but which are only provisional, the greater num-ber
The laws and mechanics of circulation, with the principle involved in animal movement . Fig. 134 —Impregnated Uterus, showing connection between villosities of chorion anddecidual membranes.—Dalton. ing ends of the growing tufts, which readily find their way intothe lumen of the expanded uterine tubules (Fig. 134), rapidlygrowing and branching in the follicular cavities, which increase 324 PHYSIOLOGICAL ANATOMY. correspondingly, the two growing pari passu with each other,the branched processes constituting the villi of the chorion(Fig. 135); but which are only provisional, the greater num-ber soon fading out, so as to make the chorion bald1 save inthe locality elected for the placenta, the portion in imme-diate contact with the walls of the womb, where they rapidlyincrease in size, as also the uterine follicles, so as to form theplacental sinuses ; the matter being one of continuous growthand amplification on the part of both. At this point thecapillary loops sent into the villi (they had previously been. Fig. 135.—Entire Human Ovum of Eighth Week, sixteen lines in length (not reckoningthe tufts) ; the surface of the Chorion partly smooth, and partly rendered shaggy bythe growth of tufts—Carpenter. only amplified epithelium, inclosed in a layer of basementmembrane) from the fcetal vessels, undergo enlargement, grow-ing rapidly, while the uterine sinuses project their thin endo-thelial lining membrane (extremely thin) into the placentalsinuses, forming the lining membrane to them, also, wherebythe maternal blood is brought into immediate contact with tJi <?placental villi, for producing rapid interchanges betweenthem, while special arrangements obtain in the womb itself(to be mentioned presently) for rapidly renewing the blood inthe sinuses, producing a continuous stream in and out of thesinuses, which the scheme calls for. The placenta, then, is composed of both fcetal and maternalstructures (Fig. 136). The structure is very dense ; more so PHYSIOLOGICAL
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Keywords: ., bookcentury1800, bookde, booksubjectblood, booksubjectrespiration
