The anterior chamber
The sclera and choroid are derived from the mesoderm surrounding the optic cup.
The lacrimal sac and nasolacrimal duct result from a thickening of the ectoderm in the groove, nasooptic furrow, between the lateral nasal and maxillary processes. This thickening forms a solid cord of cells which sinks into the mesoderm; during the third month the central cells of the cord break down, and a lumen, the nasolacrimal duct, is established. The lacrimal ducts arise as buds from the upper part of the cord of cells and secondarily establish openings (puncta lacrimalia) on the margins of the lids. The epithelium of the cornea and conjunctiva, and that which lines the ducts and alveoli of the lacrimal gland, are of ectodermal origin, as are also the eyelashes and the lining cells of the glands which open on the lid-margins.Поділитися цим:
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