Quain's elements of anatomy . Fi JO. TkAXSVEKSE section through the region OV the heart m AN EMBRYO-CHICK OF 39 HOURS. J. (From Kolliker.) m, medulla oblongata ; a, a, descending aortas ; ^)A., pharynx ; 7i, epilolast; A, thicken-ing of the same where the auditory vesicle is to be formed ; 7ip, parietal mesoblast;7izp, outer wall of the heart ; iJiA, inner wall, the cavity still divided by a sei^tuni s ;Jilb, pericardial cavity ; vhr/, ventral mesocardinm produced temporarily by the reflectionof the visceral mesoblast Ag i^ito dfp; (/, <j, vessels in the visceral niesoblast; Ent,hj^soblast.
Quain's elements of anatomy . Fi JO. TkAXSVEKSE section through the region OV the heart m AN EMBRYO-CHICK OF 39 HOURS. J. (From Kolliker.) m, medulla oblongata ; a, a, descending aortas ; ^)A., pharynx ; 7i, epilolast; A, thicken-ing of the same where the auditory vesicle is to be formed ; 7ip, parietal mesoblast;7izp, outer wall of the heart ; iJiA, inner wall, the cavity still divided by a sei^tuni s ;Jilb, pericardial cavity ; vhr/, ventral mesocardinm produced temporarily by the reflectionof the visceral mesoblast Ag i^ito dfp; (/, <j, vessels in the visceral niesoblast; Ent,hj^soblast. of the heart and the primary right and left compartments of the j)Pri-cardium. The endocardiac lining {ikh) is derived fiom the deej)er partof the visceral mesoblast. Pig. Ijetween the tvro halves of the heart; hi, blastoderm Fig. 771.—Transverse SEC-TION THROUGH THE RE-GION OP THE HEART IN Arabbits EilBRYO OF NINE DATS. ^J\ (From Kolliker.) jj, jugular veins ; ao, de-scending aortic roots ; ph,pharynx ; hp, body-wall re-flected in ect : ih, innercellular lining of the stilldivided heart; ah, outerwall of the heart; p, jjeri-cardial cavity; iff, df,visceral mesoblast ; e, pro-longation of the hypoblastof the foregut and the an-terior wall of the pericardialcavity into the partitioncnt, visceral wall. ~Ll It would appear that in both forms of the hearts origin the inflection of theTaesoblast which gives rise to its wall is at first incomi^lete. In the case of thesingle and median formation this has the effect of leaving the endocardiac waEof the rudimentary organ in immediate contact with the hypoblast of the cepha-lic part of the alimentary cavity; but very soon the further inflection of the OEIGm OF THE HEART. SGI outer mesoblastic layer of cells com
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
