The development of the human body; a manual of human embryology . branchial furrow. Another portion of the samefurrow is represented by a more or less prominent de-pression situated posteriorly to the opening of the Eusta-chian tube on each side and known as the groove ofRosenmilller. The Development of the Branchial Epithelial Bodies.—These are structures which arise either as thickenings oras outpouchings of the epithelium lining the lower portions THE BRANCHIAL EPITHELIAL BODIES. 313 of the inner branchial furrows. Five pairs of these struc-tures are developed and, in addition, there is a s
The development of the human body; a manual of human embryology . branchial furrow. Another portion of the samefurrow is represented by a more or less prominent de-pression situated posteriorly to the opening of the Eusta-chian tube on each side and known as the groove ofRosenmilller. The Development of the Branchial Epithelial Bodies.—These are structures which arise either as thickenings oras outpouchings of the epithelium lining the lower portions THE BRANCHIAL EPITHELIAL BODIES. 313 of the inner branchial furrows. Five pairs of these struc-tures are developed and, in addition, there is a single un-paired median body. This last makes its appearance inembryos of about 3 mm., and gives rise to the major por-tion of the thyreoid body. It is situated immediately be-hind the anterior portion of the tongue, at the apex of thegroove between this and the posterior portion, and is firsta slight pouch-like depression. As it deepens, its extrem-ity becomes bilobed, and after the embryo has reached alength of 6 mm. it becomes completely separated from the. Fig. 165.—Reconstructions op the Branchial Epitheual Bodies op Embryos op (A) 14 mm. and (S) 26 , Aorta; Ith, lateral thyreoid; ph, pharynx; pth1 and pth2, parathy- reoids; th, thyreoid; thy, thymus; vc, vena cava superior.—(Tourneux and Verdun.) floor of the pharynx. The point of its original origin is,however, permanently marked by a circular depression, theforamen ccecum (Fig. 161, jc). Later the bilobed bodymigrates down the neck and becomes a solid transverselyelongated mass (Fig. 165, th), into the substance of whichtrabecular of connective tissue extend, dividing it into anetwork of anastomosing cords which later divide trans-versely to form follicles. When the embryo has reacheda length of cm., a cylindrical outgrowth arises from the 3H THE DEVELOPMENT OF THE HUMAN BODY. anterior surface of the mass, usually a little to the left ofthe median line, and extends up the neck a varying dis-tance, forming,
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
