Circadian rhythm is controlled by?
ANSWER: (A) Suprachiasmatic nucleusREF: http://en.wikipedia.org/wiki/Hypothalaus, Guyton and Hall 11th edition, page 728-738, Netter's 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 brain's 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 nucleusThermoregulation/Heat loss centreSupraoptic nucleus (SO)vasopressin (ADH) releaseParaventricular nucleus (PV)CRH releaseOxytocin and to a lesser extent antidiuretic hormoneAnterior hypothalamic nudeus (AH)Thermoregulation/Heat loss centre (set point comparison) Heat loss if core temp > set pointSuprachiasmatic nudeusCircadian rhythmsPart of supraoptic nudeus (SO)vasopressin release releaseMedialDorsomedial hypothalamic nudeus (DM)Blood Pressure Heart Rate GI stimulationVentromedial nucleus (VM)satiety 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) (MB)memory feeding reflexPosterior nudeus (PN)Increase blood pressure Pupillary dilation Thermoregulation (generates shivering, if core temp <set point)Note: Paraventricular nucleus is not to be confused with periventricular nucleus.
Suprachiasmatic nucleus
Lateral nucleus
Ventromedial nucleus
Supraoptic nucleus
Thalamus, Hypothalamus and Basal Ganglia