Nelsen, Olin E. Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania.
Last reviewed:August 2020
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A tubuloalveolar or acinous skin gland, also known as the tear gland. The lacrimal glands, or tear glands, are paired structures and are found within the orbit above the lateral end of each eye in most vertebrates (see illustration). These glands develop from the skin epithelium, which folds inward over the developing eye. Two types of lacrimal glands occur among vertebrates: the lacrimal gland proper and the Harderian gland. These eye glands are first found in amphibians, associated with the inside of the lower eyelid. In urodele amphibians, the eye gland extends along the inner aspect of the lower eyelid. In fire salamanders (Salamandra), it becomes divisible into an anterior Harderian gland associated with lower eyelid structures and a posterior lacrimal gland below the upper eyelid. In frogs and toads, only the Harderian gland is present and is associated with the nictitating membrane or third eyelid, which develops in relation to the lower lid. See also: Epithelium; Eye (vertebrate); Eye disorders; Gland; Vertebrata
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