Structure and Functions (Magill’s Medical Guide, Sixth Edition)
The hypothalamus is a small, cone-shaped structure located near the center of the brain immediately below the thalamus. The hypothalamus has many nuclei and fiber tracts. It forms part of the walls and floor of the central chamber of the cerebral ventricles, which is known as the third ventricle. Neurons in the hypothalamus extend axons to the pituitary gland that is hanging on a stalk underneath the hypothalamus.
The hypothalamus controls many automatic functions of the body. Its overall function is to maintain normal, healthy conditions in the body by governing the autonomic nervous system and controlling pituitary output. Its specific functions are controlling the release of eight major hormones in the body, regulating body temperature, controlling food and water intake, controlling daily cycles in physiological state and behavior, mediating emotional responses, and regulating sexual behavior and reproduction.
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Disorders and Diseases (Magill’s Medical Guide, Sixth Edition)
If the hypothalamus is not functioning properly, the autonomic nervous system can send wrong neurosignals to the body that can make the victim feel stressed and emotionally empty. This can lead to disordered sleep, dysfunction of the immune system, altered body temperature, or multiple hormonal dysfunctions. These conditions often lead to depression, hyperactivity, malfunctioning of normal brain and limbic activities, or abnormal responses to stress. Disturbances in neural pathways that connect the hypothalamus and thalamus and control mood appear to be related to some of the symptoms of schizophrenia.
Obesity and related disorders are directly related to the critical role that the hypothalamus plays in the central regulation of appetite and metabolism. Insufficient production of antidiuretic hormone by the hypothalamus may cause diabetes insipidus. When the thirst center in the anterior hypothalamus is stimulated, polydipsia occurs, which can lead to polyuria.
Treatment of hypothalamic disorders depends on the cause of the dysfunction. If it is due to a tumor, the growth is either surgically removed or treated with radiation. If it is due to hormonal deficiencies, the missing hormones are replaced. Other specific treatments may be applied if the malfunction is due to infection, bleeding, or other causes.
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Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
The homeostatic function of the hypothalamus was suggested by Claude Bernard in the late 1800’s. Many initial studies were focused on identifying the boundaries, structural components, nuclei, tracts, and interconnections of the hypothalamus. During the latter half of the twentieth century, interest shifted to the functions of the hypothalamus that were involved in emotional expression, disease, controlling metabolism, and producing neuroendocrine secretions. This emphasis has led to a better understanding and treatment of medical problems and chemical imbalances associated with hypothalamic dysfunctions.
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Hadley, Mac E., and Jon E. Levine. Endocrinology 6th ed. Upper Saddle River, N.J.: Pearson, 2007.
Stoll, Walt, and Jan DeCourtney. Recapture Your Health. Boulder, Colo.: Sunrise Health Coach, 2006.
Swaab, Dick F. Human Hypothalamus: Basic and Clinical Aspects, Part 2: Handbook of Clinical Neurology. Amsterdam: Elsevier, 2003.
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Hypothalamus (Encyclopedia of Psychology)
A section of the forebrain, connected to other parts of the forebrain and midbrain, that is involved in many complex behaviors.
The hypothalamus, which together with the thalamus makes up the section of the forebrain called the diencephalon, is involved in such aspects of behavior as motivation, emotion, eating, drinking, and sexuality. Lying under the thalamus, the hypothalamus weighs only a fraction of an ounce and is a little larger than the tip of the thumb. It is connected to the autonomic nervous system, and controls the entire endocrine system using the pituitary gland to direct the work of all the other endocrine glands. If a particular section of the hypothalamus is destroyed, an overwhelming urge to eat results; damage to another section of a male's hypothalamus can reduce the sex drive. Yet another part of the hypothalamus, the suprachiasmatic nuclei (SCN), is the site of a person's "internal clock" that regulates biological rhythms according to a cycle of roughly 24 hours. From the SCN, signals reach areas of the hindbrain that regulate sleep and wakefulness. With neurons firing on a 24-or 25-hour cycle, it determines the periods of greatest alertnesshether one is "morning person" or a "night person." Pathways from the SCN to the eyes connect its circadian rhythms to external cycles of light and...
(The entire section is 319 words.)