* Pituitary gland: Often called the "master gland" because it controls the activity of other endocrine glands. It is located at the base of the brain, connected to the hypothalamus.

* Hypothalamus: This structure regulates many bodily functions, including hunger, thirst, body temperature, and sleep. It also controls the release of hormones from the pituitary gland.

* Pineal gland: Located in the center of the brain, it secretes melatonin, a hormone that helps regulate sleep patterns.

While not technically *in* the brain, the thyroid gland is also regulated by the hypothalamus and pituitary gland.