Blood levels of the pineal hormone melatonin are high at night and low during the day Its secretion is regulated by a rhythm-generating system located in the suprachiasmatic nucleus of the hypothalamus, which is in turn regulated by light Melatonin ....
Sep 04, 2012· Get YouTube without the ads Working, Skip trial 1 month free Find out why Close Вибрационный грохот, виброгрохот (Китай) , Моющий грохот ....