Becoming a Citizen in a Democratic Society

Melatonin essays

Melatonin essays The pineal body, also known as the pineal gland, is a small structure extending from the posterior border of the brain within the third ventricle and along the midline (1,2). It is not actually part of the brain, but a member of the endocrine system (1). This pea-sized, pine coned shape structure was first given attention to in 1963 when it was discovered that its chief secretion, melatonin, was involved with various organ and tissue regulation (3). Before then, the structure was only believed to be the remains of a primitive sensory system (3). Much is still unknown about this member of the endocrine system. Melatonin is the major secretory product of the pineal body although many peptide and amine secretions have been recognized coming from this structure (1). Melatonins primary role is in the regulation of circadian rhythms, including sleep/wake cycles and core body temperature, and is sometimes called the master hormone because of this (3). However, it is uncertain whether it can fully regulate all human circadian rhythms (4). The chemical structure of melatonin is small and similar to that of serotonin (3). It is distributed to various organs and tissues through the circulatory system as a hormone and secretion levels rise at night because it is stimulated by darkness and suppressed by light (3,5). This is because is it synthesized by photoreceptor structures in the pineal gland which receive input indirectly from visual pathways (1,5). High melatonin levels cause drowsiness and most people prefer to sleep at night because the darkness stimulates melatonin secretion (3). Oral doses of melatonin can shift the bodys clock forward or backward making it a treatment for insomnia, jet lag, seasonal depression and time changes, although a possible side effect may be daytime drowsiness in a few sensitive people (3). Melatonin may also be a possible treatment for certain cancers. Women with e...