Oxytocin: A hormone made in a part of the brain called the hypothalamus that causes the uterus to contract and milk to be released into the milk ducts of the breast during breastfeeding. (acog.org)
The main cog in the human biological clock is the suprachiasmatic nucleus (SCN), a group of nerve cells in a region at the base of the brain called the hypothalamus. (scientificamerican.com)
The signals are received in a structure at the base of the brain called the hypothalamus. (scientificamerican.com)