hypothalamus

Examples of hypothalamus in the following topics:

• The Endocrine System and Hunger

  • Hunger is controlled by the hypothalamus and hormones.
  • The hypothalamus regulates the body's physiological homeostasis.
  • In the 1940s, the "dual-center" model, which divided the hypothalamus into hunger (lateral hypothalamus) and satiety (ventromedial hypothalamus) centers, was popular.
  • This theory developed from the findings that bilateral lesions of the lateral hypothalamus can cause anorexia, a severely diminished appetite for food, while bilateral lesions on the ventromedial hypothalamus can cause overeating and obesity.
  • When blood sugar levels fall, the hypothalamus is stimulated.

• Lower-Level Structures

  • The diencephalon is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus, and the epithalamus.
  • The hypothalamus is a small part of the brain located just below the thalamus.
  • Lesions of the hypothalamus interfere with motivated behaviors like sexuality, combativeness, and hunger.
  • The hypothalamus also plays a role in emotion: parts of the hypothalamus seem to be involved in pleasure and rage, while the central part is linked to aversion, displeasure, and a tendency towards uncontrollable and loud laughing.
  • An image of the brain showing the location of the hypothalamus.

• The Limbic System

  • There are several important structures within the limbic system: the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus.
  • Both the thalamus and hypothalamus are associated with changes in emotional reactivity.
  • The hypothalamus is a small part of the brain located just below the thalamus on both sides of the third ventricle.
  • Lesions of the hypothalamus interfere with several unconscious functions (such as respiration and metabolism) and some so-called motivated behaviors like sexuality, combativeness, and hunger.
  • The lateral parts of the hypothalamus seem to be involved with pleasure and rage, while the medial part is linked to aversion, displeasure, and a tendency for uncontrollable and loud laughter.

• The Endocrine System and Stress

  • The hypothalamic-pituitary-adrenal (HPA or HTPA) axis is a complex set of direct influences and steroid-producing feedback interactions among the hypothalamus, the pituitary gland, and the adrenal glands.
  • The hypothalamus contains neurons that synthesize and secrete vasopressin and corticotropin-releasing hormone (CRH).
  • This causes a negative feedback cycle in which the steroids inhibit the hypothalamus and the pituitary gland, and it also causes the adrenal gland to produce the hormones epinephrine (also known as adrenaline) and norepinephrine.

• Biology of Emotion

  • Its structures include the hypothalamus, thalamus, amygdala, and hippocampus.
  • The hypothalamus plays a role in the activation of the sympathetic nervous system, which is a part of any emotional reaction.
  • It has connections with the hypothalamus and various areas of the brainstem and regulates the activity of the autonomic nervous and endocrine systems (Pessoa, 2010).
  • It is regulated by the hypothalamus and controls our internal organs and glands, including such processes as pulse, blood pressure, breathing, and arousal in response to emotional circumstances.
  • Its structures include the hypothalamus, thalamus, amygdala, and hippocampus

• Biology of Sexual Behavior

  • The hypothalamus is the most important part of the brain for sexual functioning.
  • Studies with lab animals have shown that destruction of certain areas of the hypothalamus causes complete elimination of sexual behavior.
  • One of the reasons for the importance of the hypothalamus is its relation to the pituitary gland, which secretes the hormones that are produced in the hypothalamus.

• How the Body Responds to Stress

  • The hypothalamic–pituitary–adrenal axis (HPA axis) is a complex set of direct influences and feedback interactions among three endocrine glands: the hypothalamus, the pituitary gland, and the adrenal glands.
  • The sympathetic nervous system regulates the stress response via the hypothalamus.
  • Stressful stimuli cause the hypothalamus to signal the adrenal medulla (which mediates short-term stress responses) via nerve impulses, and the adrenal cortex (which mediates long-term stress responses) via the hormone adrenocorticotropic hormone (ACTH), which is produced by the anterior pituitary.
  • The sympathetic nervous system regulates the stress response via the hypothalamus.

• Circadian Rhythms

  • The SCN is a small group of brain cells located in the hypothalamus that controls the circadian cycles and influences many physiological and behavioral rhythms occurring over a 24-hour period, including the sleep/wake cycle.
  • The SCN contains about 20,000 nerve cells, and is located in the hypothalamus, above the optic nerves.

• Development of the Human Brain

  • The diencephalon is lower, containing the thalamus and hypothalamus (which together form the limbic system); the telencephalon is on top of the diencephalon and contains the cerebrum, the home of the highest-level cognitive processing in the brain.

• Conscious vs. Unconscious Emotion

  • The limbic system is a complex set of brain structures that includes the hypothalamus, hippocampus, amygdala, and other nearby areas of the brain .