| pineal | A gland-like structure in the brain which appears to be the major site of melatonin biosynthesis. The exact role of the pineal remain obscure. (27 Sep 1997) |
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| pineal body | A small conical midline body attached to the posterior part of the third ventricle and lying between the superior colliculi, below the splenium of the corpus callosum. (12 Dec 1998) |
| pineal cells | Cell's of the corpus pineale or pinealocyte. (05 Mar 2000) |
| pineal cyst | A cyst of the pineal gland; rarely of clinical importance. (05 Mar 2000) |
| pineal eye | A non-image-forming, photoreceptive eye in or near the median line in certain crustacea and lower vertebrates; homologue of pineal gland in higher forms. Synonym: epiphysial eye, parietal eye. (05 Mar 2000) |
| pineal gland | A small, flat gland found within the brain which produces the hormones melatonin and serotonin. (09 Oct 1997) |
| pineal gland calcification | <radiology> Visible on plain skull film (33-76% in adults), seen more frequently on CT, rare in kids less than 6 y.o. (presence suggests neoplasm), usually in the form of a cluster of amorphous, irregular densities, may be solitary, the size of calcification: usually 3-5 mm, if greater than 1 cm, suspect pinealoma, AV malformation, etc. See: physiological intracranial calcifications (12 Dec 1998) |
| pineal habenula | The peduncle or stalk of the pineal gland. See: habenula. (05 Mar 2000) |
| pineal recess | A diverticulum from the posterior part of the third ventricle extending back between the posterior commissure and the habenular commissure. Synonym: recessus pinealis. (05 Mar 2000) |
| pineal region tumours | Type of brain tumours. (12 Dec 1998) |
| pineal tumours | <radiology> SIGNS: aqueductal obstruction most likely to be hydrocephalus, paralysis of upward gaze (due to pressure on quarigeminal plate), precocious puberty, symptoms of hypothalamic, thalamic, cerebellar or pyramidal lesion TYPES: germ-cell (teratoid) tumours, teratoma, germinoma / atypical teratoma, endodermal sinus (yolk sac) tumour, choriocarcinoma, pineal-cell tumours, pineocytoma, pineo---, others, glioma, ganglioneuroma, ganglioglioma (12 Dec 1998) |
| pinealectomy | Removal of the pineal body. Origin: pineal + G. Ektome, excision (05 Mar 2000) |
| pinealocyte | A cell of the pineal body with long processes ending in bulbous expansions. Pinealocytes receive a direct innervation from sympathetic neurons that form recognizable synapses. The club-shaped endings of pinealocyte processes terminate in perivascular spaces surrounding capillaries. Synonym: chief cell of corpus pineale, parenchymatous cell of corpus pineale. Origin: pineal + G. Kytos, cell (05 Mar 2000) |
| pinealoma | A tumour of the pineal body composed of neoplastic nests of large cells. Tumours in this region are rare, accounting for less than 1% of intracranial tumours, although in children they constitute 3%-8% of intracranial tumours. Its symptoms include hydrocephalus, conjugate paralysis of upward gaze, disturbances of gait, and precocious puberty, the last due to suppression of pineal secretion of melatonin. Because pinealomas are near the centre of the brain, they are among the most difficult of brain tumours to remove. A variety of surgical approaches has been described. Radiotherapy and chemotherapy are also used. (12 Dec 1998) |
| pinealopathy | Disease of the pineal gland. Origin: pineal + G. Pathos, disease (05 Mar 2000) |
| pedunculus of pineal body | See: habenula. (05 Mar 2000) |
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