The hypothalamus is a brain structure that is part of the limbic system. This small structure is tasked primarily with regulating the endocrine system and autonomic nervous system.
Structure and Location of the Hypothalamus
Located above the brain stem and just below the thalamus, the hypothalamus is about the size of a fingernail. The pituitary gland is attached to the base of the hypothalamus and links the endocrine system to the nervous system.
The hypothalamus is divided into three regions:
Each region contains a group of nuclei that play an important role in the structure and function of the hypothalamus. Nuclei are clusters of neurons that perform related functions. There are numerous nuclei located in the hypothalamus, including the supraoptic nucleus, the ventromedial nucleus, and the lateral nucleus. Each nucleus plays a distinct role.
Functions of the Hypothalamus
Despite its small size, the hypothalamus performs a diverse array of functions, including:
- Maintaining homeostasis—the relatively consistent maintenance of internal functions—by monitoring temperature, heart rate, and other vital functions.
- Contributing to the regulation of the sleep-wake cycle and daily cycles—also known as circadian rhythm. The hypothalamus is highly sensitive to light, and when light cycles are interfered with—such as in parts of the world where it is light or dark most of the time—sleep may be disturbed.
- Reacting to external conditions that threaten homeostasis. The hypothalamus is responsible for shivering, sweating, for contributing to feelings of hunger and thirst, and for lowering or increasing blood pressure in response to external signals.
- Releasing oxytocin, a bonding hormone that plays a role in breastfeeding, orgasm, childbirth, bonding, and feelings of parental protectiveness and love.
- Releasing the Gonadotropin-releasing hormone, which plays an important role in puberty and sexual differentiation.
- Audesirk, T., Audesirk, G., & Byers, B. E. (2008). Biology: Life on earth with physiology. Upper Saddle River, NJ: Pearson Prentice Hall.
- Colman, A. M. (2006). Oxford dictionary of psychology. New York, NY: Oxford University Press.
Last Updated: 08-10-2015