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The primary function of the hypothalamus is to link the endocrine system with the autonomic nervous system in order to maintain a state of homeostasis in the body. A small structure located above the brain stem, the hypothalamus has a complex system of inputs and outputs. These allow it to quickly respond to changing conditions and ensure the body adjusts accordingly. Basic functions such as sleep cycles, feelings of hunger or thirst, and regulation of body temperature are among its many tasks. It also controls many aspects of the reproductive system and is the site of emotions.
Through the release of special neurohormones, the hypothalamus controls the pituitary gland, the master gland of the endocrine system. These chemical signals activate the various functions of the pituitary gland when the hypothalamus senses it is necessary. In turn, the pituitary gland releases other hormones into the bloodstream. These hormones control the other endocrine glands and a vast array of metabolic functions in the body. The function of the hypothalamus in controlling hunger and thirst, sexual functioning and growth is accomplished through this system.
Although the mechanism of action is not completely understood, the hypothalamus controls the appetite and maintains a stable body weight. It receives sensory data including smell, taste and the fullness of the stomach. Based on these signals, it initiates feelings of hunger or satiation. This function of the hypothalamus is considered important for understanding the success or failure of weight loss programs. Dysfunctions in the hypothalamus-pituitary-adrenal axis may play a role in some eating disorders.
While the hypothalamus sends chemical signals to the endocrine system, it sends neural signals to the autonomic nervous system. Through its connection with the autonomic nervous system, the hypothalamus controls pulse rate, blood pressure, breathing and digestion. It gathers sensory data from internal organs, the skin, the eyes, blood vessels and elsewhere. The hypothalamus interprets all this information on a continual basis, sending neural signals that activate the sympathetic and parasympathetic systems of the autonomic nervous system as needed. The main objective is to preserve the state of homeostasis in the body.
Injuries, infections, genetic disorders and other conditions can alter the function of the hypothalamus. This may cause a wide range of dysfunctions in the intricate systems controlling the endocrine glands and the autonomic nervous system. In children, dysfunction can lead to excessive or impaired growth, and an onset of puberty that is too early or too late. The thyroid or adrenal glands may be overactive or underactive, affecting numerous metabolic processes. Eating disorders, and excessive thirst or urination might occur.
Emotional and related physical problems might manifest if the hypothalamus is impaired. The inability to accurately interpret and respond to sensory input might result in depression, sleep disorders, or hyperactivity. Since the hypothalamus plays a role in the emotions and behavior as well as the autonomic nervous system, any loss of function can alter how a person responds to stress. It is believed that the immune system’s functioning is also connected to the hypothalamus. As a result, impairment of this structure may result in a faulty immune response.