PSYCH 2E03 Lecture Notes - Pineal Gland, Suprachiasmatic Nucleus, Optic Chiasm
13 Jun 2013
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Document Summary
Retina, hypothalamus, pineal gland & circadian rhythm the link for photo-entrainment resides in retina. Photo-entrainment: alignment or synchronizing of biological rhythms (cycles) to ambient light-dark cycles connection between photo signals from outside and biological cycle rods and cones not the exclusive receptors of retina. Axons of melanopsin ganglion cell along optic nerve. Axons of melanopsin ganglion cell traced to suprachiasmatic nucleus of hypothalamus. Photopigments in ganglion cells orchestrating suprachiasmatic nucleus. No direct connect to the optic chiasm. Nocturnal animals once you start exposing to light the levels come down, in the night they go up. Diurnal animals difference in melatonin levels: in night we build up melatonin, sleep cycles go along with melanopsin. Why are the systems different: different signal patterns in both systems. Nocturnal animals: melatonin increases during day day time sleepiness. Diurnal animals: melatonin increases during night light-time sleepiness.
