Pineal Gland or Epiphysis Synthesizes Secretes Melatonin Simple

Pineal Gland or Epiphysis Synthesizes & Secretes Melatonin Simple hormone that communicates information about: Environmental Lighting to various body parts. 12/12/2021 1

The Hypothalamus 12/12/2021 2

Pineal Gland or Epiphysis Has ability to entrain: Biological Rhythms and Effects on Reproductive Function of many animals. Light - Transducing ability has led some to call it: “Third Eye". 3

Anatomy of the Pineal Gland Shaped like a pine cone (hence its name), Located on the midline, Attached to the brain’s Third Ventricular Roof Posterior end. 12/12/2021 4

Pineal Gland or Epiphysis In humans roughly 1 cm long grayish bump in front of the cerebellum, Histologically: Composed of “Pinealocytes"& Glial Cells Often contains Calcium Deposits (“Brain Sand") In older animals. 12/12/2021 5

Retina Transmits to Hypothalamus . Light exposure to the retina is first relayed to the Suprachiasmatic nucleus of the hypothalamus, an area of the brain well known to coordinate biological clock signals. 12/12/2021 6

Hypothalamus --- Spinal Cord Fibers from the hypothalamus descend to the Spinal Cord and ultimately project to the Superior Cervical Ganglia, from which post-ganglionic neurons ascend back to the pineal gland. 12/12/2021 7

Superior Cervical Sympathetic to Pineal Thus, the Pineal is similar to the Adrenal Medulla in the sense that it Transduces signals from the sympathetic nervous system into a hormonal signal. Serotonin is precursor to Melatonin, 12/12/2021 8

The Pineal Serotonin a neurotransmitter that itself is derived from the amino acid Tryptophan. Serotonin is acetylated and then methylated to yield Melatonin. 12/12/2021 9

Acetylation Then Oximethylation of Serotonin 12/12/2021 10