Introduction to Psychology 10th Edition by Rod Plotnik,Haig Kouyoumdjian

Exercise 23

Near the center of the human brain is an oval group of cells, collectively called the pineal gland, that secrete a hormone called (a) _____. The gland secretes the hormone during dark periods and stops when it gets light. In many animals, this hormone plays a major role in the regulation of (b) _____rhythms.