Tincture of iodine recommended source of solely-nutritional iodine. Nutritional iodine is better supplied in the form of the less toxic iodide (see SSKI) or iodate salts, which the body can easily convert to thyroid hormone. Nevertheless, the iodide in tincture of iodine used as a water disinfectant does supply more than adequate nutritional iodine, perhaps 30 or more times the recommended daily allowance per liter or quart. Application of tincture or Lugol's to the skin also results in absorption and bioavailability of some moderate fraction of the iodine. Tincture of iodine Tincture of iodine, iodine tincture, or weak iodine solution is an antiseptic.
Pineal gland retina of the lateral eyes of vertebrates. In most vertebrates, exposure to light sets off a chain reaction of enzymatic events within the pineal gland that regulates circadian rhythms. In humans and other mammals, the light signals necessary to set circadian rhythms are sent from the eye through the retinohypothalamic system to the suprachiasmatic nuclei (SCN) and the pineal gland. The fossilized skulls of many extinct vertebrates have a pineal foramen (opening), which in some cases is larger than that of any living vertebrate. Although fossils seldom preserve deep-brain soft anatomy, the brain of the Russian fossil bird "Cerebavis cenomanica"