The diencephalon is the region of the brain that contains the hypothalamus. The hypothalamus is also identified as part of the endocrine system and as such deals with the chemical production in the body. This part of the brain controls many body activities and is a regulator of homeostasis. The hypothalamus is a link of integration between the endocrine and nervous systems. It deals with activities of the autonomic nervous system (ANS). It regulates the heart rate, the contractions of smooth muscle, and the movement of food through the intestinal tract.

There are several hormones produced by the hypothalamus that work directly with the pituitary gland. The hypothalamus is the master controller of the pituitary gland. The pituitary gland in turn influences the production of many of the hormones in the body.

This small section of the brain, the hypothalamus, is the pleasure/ pain center. This area regulates your extreme feelings and your behavior regarding these emotions. This is also the area that tells you when you are hungry, when you are full, and when you are thirsty.

Even your sleep patterns have roots within the hypothalamus. Here is where your daily sleep program is established. The temperature of the flow of blood through the hypothalamus regulates your body temperature. When the blood is too hot, the ANS receives information to cool it down, and the opposite occurs if the blood is too cold. The reflex for this part of the brain is essentially the same as that of the pituitary.