. Cunningham's Text-book of anatomy. Anatomy. 58 HUMAN EMBRYOLOGY. begins to circulate within them and the plasmodium becomes divided into three series of Spongy layer | Placental area Unchanged layer of decidua stratum spongiosum Intervillous Maternal blood-ve Muscular wall of uteru Uterine tube Mesoderm lining trophoblast Trophoblast Unchanged part of gland Dilated part of gland' Cavity of uterus _J. ondary villus â Amnion cavity Amnion -Body-stalk Allantoic diverti- culum rimitive streak eurenteric canal Cavity of entoderm sac Extra-embryonic celom Decidua capsularis Decidua vera Embryonic
. Cunningham's Text-book of anatomy. Anatomy. 58 HUMAN EMBRYOLOGY. begins to circulate within them and the plasmodium becomes divided into three series of Spongy layer | Placental area Unchanged layer of decidua stratum spongiosum Intervillous Maternal blood-ve Muscular wall of uteru Uterine tube Mesoderm lining trophoblast Trophoblast Unchanged part of gland Dilated part of gland' Cavity of uterus _J. ondary villus â Amnion cavity Amnion -Body-stalk Allantoic diverti- culum rimitive streak eurenteric canal Cavity of entoderm sac Extra-embryonic celom Decidua capsularis Decidua vera Embryonic are Fig. 75.âSchema of a Section of a Pregnant Uterus after the formation of the Intervillous Spaces. parts. (1) The parts which lie between adjacent blood spaces, the primary chorionic villi. (2) The parts which lie in con- tact with the mesoderm of the chorion, and which form with the mesoderm the chorion plate. (3) The parts which cover the maternal tissues and form the outer boun- daries of the blood spaces, the basal layer. The blood spaces themselves are called the in- tervillous spaces (Figs. 76, 79). After a time each primary villus differenti- ates into a cellular core and plasmodial periphery, and thereafter the villi are invaded by the mesoderm of the chorion and are thus converted into secondary villi (Fig. 76). The first-formed villi are non-vascular, but by the time the secondary villi have developed the um- bilical arteries have grown through the body-stalk (allantoic stalk) into the meso- derm of the chorion, and branches from them enter the meso- dermal cores of the villi, which thus be- come vascular. When the second- ary villi are fully developed each con- sists of a vascular mesodermal core con- tinuous with the mesoderm of the chorion Thp mpsn / 6.âSchema of a Frontal Section of a Pregnant Uterus at the vj uxi. luesu- period of the Formation of the Embryo. Xote extension of amnion dermal core IS Covered as contrasted with stage shown in Fi°- 75
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
