Structure and Functions of the Hypothalamus

Vocabulary practice flashcards covering the anatomical structure, homeostatic roles, autonomic connections, endocrine pathways, food intake controls, and thermoregulation of the hypothalamus based on lecture notes.

Hypothalamus

A small structure, roughly the size of an almond, located at the base of the brain above the brainstem and below the thalamus that maintains homeostasis and links the nervous and endocrine systems.

Suprachiasmatic Nucleus

A key nucleus within the hypothalamus that acts as the biological clock.

Homeostatic Negative Feedback Circuit

The mechanism by which the hypothalamus receives sensory signals of the physiological state, calculates the difference from a programmed set-point, and initiates a compensatory cascade to correct deviations.

Hypothalamic-Pituitary-Adrenal (HPA) Axis

An axis whose stimulation by the hypothalamus can trigger diffuse sympathetic discharge and increase secretion from the adrenal medulla during the fight or flight response.

Posterior Pituitary (Neurohypophysis)

The region that receives vasopressin (ADH) and oxytocin synthesized in the supraoptic and paraventricular nuclei via the hypothalamic-hypophysial tract for release into the blood.

Hypothalamic-Hypophysial Tract

The axonal pathway through which vasopressin (ADH) and oxytocin are transported from the supraoptic and paraventricular nuclei to the posterior pituitary.

Anterior Pituitary (Adenohypophysis)

The region controlled by hypophysiotropic hormones (releasing and inhibitory factors) secreted by the hypothalamus into a specialized portal circulation.

Releasing Hormones (Liberins)

Hypophysiotropic hormones secreted into portal circulation, including TRH (Thyrotropin), PRH (Prolactin), GHRH (Growth hormone), GnRH (Gonadotropin), and CRH (Corticotropin).

Inhibiting Hormones (Statins)

Hypophysiotropic hormones secreted into portal circulation, including Somatostatin (which inhibits growth hormone and TSH) and Dopamine (which inhibits prolactin).

Hunger Center

A region located in the lateral hypothalamus where stimulation causes voracious eating and destruction leads to starvation.

Satiety Center

A region located in the ventromedial hypothalamus that inhibits the hunger center; stimulation induces satiety, while destruction leads to overeating and obesity.

Orexigenic Neurotransmitters

Appetite-stimulating neurotransmitters involved in food intake regulation.

Anorexigenic Neurotransmitters

Appetite-suppressing neurotransmitters involved in food intake regulation.

Thermoregulatory Center

A center located in the preoptic area of the hypothalamus that receives input from peripheral skin thermoreceptors and central CNS sensors.

Heat-Losing Center

A thermoregulatory center activated when blood is warmer than the set-point; it triggers sweating and skin arteriole vasodilation while inhibiting the heat-promoting center.

Heat-Promoting Center

A thermoregulatory center activated when blood is cooler than the set-point; it triggers skin arteriole vasoconstriction, shivering, and non-shivering thermogenesis while inhibiting the heat-losing center.