<prompt> Circadian rhythm is controlled by?Suprachiasmatic nucleusLateral nucleusVentromedial nucleusSupraoptic nucleus  <response>: ANSWER: A Suprachiasmatic nucleusREF: Guyton and Hall 11th edition, page 728-738, Netters Atlas of human physiology, page 18See APPENDIX-12 below for detailsRepeat from June 2008 8c December 2010The suprachiasmatic nucleus or nuclei, abbreviated SCN, is a tiny region on the brains midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24- hour cycle APPENDIX - 12RegionAreaNudeusFunctionAnteriorMedialPreoptic nucleusThermoregulationHeat loss centreSupraoptic nucleus SOvasopressin ADH releaseParaventricular nucleus PVCRH releaseOxytocin and to a lesser extent antidiuretic hormoneAnterior hypothalamic nudeus AHThermoregulationHeat loss centre set point comparison Heat loss if core temp set pointSuprachiasmatic nudeusCircadian rhythmsPart of supraoptic nudeus SOvasopressin release releaseMedialDorsomedial hypothalamic nudeus DMBlood Pressure Heart Rate GI stimulationVentromedial nucleus VMsatiety centre controls eating lesion causes voracious appetiteArcuate nucleus AR Infundibular nucleus Periventricular nucleusEndocrine function releasing hormones - controls AdenohypophysisLateralLateral hypothalamic areaFeeding centre thirst and hunger - lesion causes anorexiaMedialMammillary nuclei part of mammillary bodies MBmemory feeding reflexPosterior nudeus PNIncrease blood pressure Pupillary dilation Thermoregulation generates shivering, if core temp 