The hypothalamus performs several functions, the main one being homeostasis. Other functions are hormone production and controlling some glands, including the pituitary gland and the adrenal gland. Homeostasis is how the body controls such autonomic processes such as a balanced temperature, respiration and blood pressure.
The hypothalamus is pearl sized and is involved in other processes such as the sleep-wake cycle and motor function. The hypothalamus, because of its role in making hormones, can affect a person's emotions, especially in the areas of hunger, sex drive, moods and thirst. The hypothalamus uses a body set point to make adjustments in various autonomic systems.