an eyelike structure that develops from the pineal apparatus in certain cold-blooded vertebrates.
an outgrowth of the pineal gland that forms an eyelike structure on the top of the head in certain cold-blooded vertebrates
A sensory structure capable of light reception, appearing as a spot on the top of the head in lampreys, hagfish, amphibians, and some reptiles, especially the tuatara. Pineal eyes can contain a rudimentary cornea, lens, cone cells, and retina, and are thought to be sensitive to light and dark but not to be able to form images.
noun 1. a small, cone-shaped endocrine organ in the posterior forebrain, secreting melatonin and involved in biorhythms and gonadal development. noun 1. a pea-sized organ in the brain, situated beneath the posterior part of the corpus callosum, that secretes melatonin into the bloodstream Technical names epiphysis, epiphysis cerebri pineal gland n. See pineal body. pineal […]
pinealocyte pin·e·a·lo·cyte (pĭn’ē-ə-lō-sīt’, pī’nē-, pĭ-nē’-, pī-nē’-) n. A cell of the pineal body having long processes ending in bulbous expansions.
pinealoma pin·e·a·lo·ma (pĭn’ē-ə-lō’mə, pī’nē-) n. pin·e·a·lo·mas or pin·e·a·lo·ma·ta (-mə-tə) A neoplasm derived from the pineal body and characterized by large, round, or polygonal cells with large nuclei and small cells that resemble lymphocytes.
- Pineal stalk
pineal stalk n. The attachment of the pineal body to the roof of the third ventricle, containing the pineal recess of the third ventricle.