. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. THE LACHRYMAL GLAND 467 The lachrymal gland is developed at about the third month as a number of branching outgrowths of the ectoderm into the adjacent mesoderm along the outer part of the line where the epithelium of the conjunctiva becomes continuous with that covering the inner surface of the upper eyelid. As in the other epidermal glands, the outgrowths and their branches are at first solid, later becoming hol- low by the degeneration of their axial cells. The naso-lachrymal duct is devel
. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. THE LACHRYMAL GLAND 467 The lachrymal gland is developed at about the third month as a number of branching outgrowths of the ectoderm into the adjacent mesoderm along the outer part of the line where the epithelium of the conjunctiva becomes continuous with that covering the inner surface of the upper eyelid. As in the other epidermal glands, the outgrowths and their branches are at first solid, later becoming hol- low by the degeneration of their axial cells. The naso-lachrymal duct is developed in connection with the groove which, at an early stage in the development (Fig. 62), extends. Fig. 280.—Diagram showing the Insertions of the Lachrymal Ducts in- EMBRYOS OF 40 MM. AND 170 THE CaRUNCULA LaCRIMALIS BEING FORMED IN the Latter. The eyelids are really fused at these stages but have been represented as separate • for the sake of clearness.—(Ask.) from the inner corner of the eye to the olfactory pit and is bounded posteriorly by the maxillary process of the first visceral arch. The epithelium lying in the floor of this groove thickens toward the begin- ing of the sixth week to form a solid cord, which sinks into the sub- jacent mesoderm. From its upper end two outgrowths arise which become connected with the ectoderm of the edges of the upper and lower lids, respectively, and represent the lachrymal ducts, and, finally, the solid cord and its outgrowths acquire a lumen and a connection with the mucous membrane of the inferior meatus of the nasal cavity. The inferior duct connects with the border of the eyelid some distance lateral to the inner angle of the eye, and between its open- ing and the angle a number of tarsal glands develop. The superior duct, on the other hand, opens at first close to the inner angle and. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration a
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