Hypothalamus & Limbic System – Vocabulary Flashcards

Comprehensive vocabulary flashcards covering structures, hormones, nuclei, and key functions discussed in Lecture #13 on the hypothalamus and limbic system.

Hypothalamus

Diencephalic structure below the thalamus that links the nervous and endocrine systems and maintains homeostasis.

Limbic System

Interconnected cortical and subcortical loop (primitive cortex) governing emotion, memory, motivation, and social behavior.

Magnocellular Neurons

Large hypothalamic neurons whose axons project to the posterior pituitary to release vasopressin and oxytocin.

Parvicellular Neurons

Small hypothalamic neurons that release regulating hormones into the median eminence for anterior-pituitary control.

Posterior Pituitary

Neurohypophysis that stores and releases hypothalamic hormones vasopressin and oxytocin into blood.

Vasopressin (ADH)

Antidiuretic hormone from magnocellular neurons; increases renal water reabsorption and blood volume.

Oxytocin

Posterior-pituitary hormone that induces uterine contraction and milk ejection; also influences bonding behavior.

Anterior Pituitary

Adenohypophysis that secretes TSH, ACTH, FSH/LH, GH, and prolactin under hypothalamic releasing hormones.

Median Eminence

Vascular region at hypothalamic base where parvicellular neurons secrete releasing hormones into portal blood.

Thyrotropin-Releasing Hormone (TRH)

Hypothalamic peptide that stimulates anterior pituitary secretion of TSH.

Thyroid-Stimulating Hormone (TSH)

Anterior-pituitary hormone that prompts thyroid gland to produce thyroid hormones.

Corticotropin-Releasing Hormone (CRH)

Hypothalamic hormone that triggers ACTH release from the anterior pituitary.

Adrenocorticotropic Hormone (ACTH)

Anterior-pituitary hormone that activates cortisol secretion from the adrenal cortex.

Gonadotropin-Releasing Hormone (GnRH)

Hypothalamic decapeptide that stimulates FSH and LH release.

Follicle-Stimulating Hormone (FSH)

Anterior-pituitary gonadotropin acting on testes and ovaries for gametogenesis.

Luteinizing Hormone (LH)

Anterior-pituitary hormone regulating ovulation and testosterone production.

Growth Hormone-Releasing Hormone (GHRH)

Hypothalamic hormone that promotes GH secretion.

Growth Hormone (GH)

Anterior-pituitary hormone stimulating body growth and metabolism.

Prolactin-Releasing Hormone (PRH)

Hypothalamic signal that enhances prolactin secretion.

Prolactin

Anterior-pituitary hormone stimulating mammary gland development and milk production.

Suprachiasmatic Nucleus (SCN)

Hypothalamic clock center that sets circadian rhythms via melatonin pathways.

Thermoregulation

Hypothalamic control of core body temperature through behavioral and physiological mechanisms.

Temperature Setpoint

Regulated core temperature around 37 °C (98.6 °F) for humans.

Hyperthermia

Body temperature elevation; convulsions at 41 °C, death near 43 °C.

Hypothermia

Core temperature drop; loss of thermoregulation near 28 °C leads to fatal decline without intervention.

Peripheral Thermoreceptors

Skin receptors detecting cold to activate posterior hypothalamus responses.

Central Thermoreceptors

Anterior-hypothalamic sensors monitoring core temperature shifts.

Shivering

Involuntary muscle activity increasing heat production during cold stress.

Thirst Center

Hypothalamic area containing osmoreceptors that initiate drinking behavior.

Osmoreceptor

Hypothalamic neuron with mechanosensitive Na⁺ channels that detect plasma osmolarity changes.

SON & PVN

Supraoptic and paraventricular nuclei housing ADH- and oxytocin-secreting magnocellular neurons.

Feeding Center

Lateral hypothalamic region whose activation stimulates appetite; lesions cause anorexia.

Satiety Center

Ventromedial hypothalamus that suppresses feeding; lesions induce hyperphagia.

Neuropeptide Y (NPY)

Potent hypothalamic peptide that stimulates food intake and promotes fat storage.

Ghrelin

Stomach-derived ‘hunger hormone’ that activates hypothalamic appetite pathways, especially after weight loss or stress.

Orexins (Hypocretins)

Hypothalamic neuropeptides promoting wakefulness and stimulating appetite.

Leptin

Adipocyte hormone that inhibits hunger by counteracting NPY and suppressing orexins.

Insulin (satiety role)

Pancreatic hormone that mildly inhibits appetite; parallels leptin effects.

Cholecystokinin (CCK)

Gut peptide rapidly released by protein/fat intake; induces satiety.

Peptide YY (PYY)

Intestinal hormone released mainly by fat ingestion; slower, sustained satiety signal.

Homeostasis

Physiological maintenance of stable internal conditions, chiefly overseen by the hypothalamus.

Autonomic Control

Hypothalamic regulation of sympathetic and parasympathetic outputs for cardiovascular and visceral functions.

Nucleus Accumbens

Basal forebrain limbic nucleus critical for reward and addictive behaviors via dopaminergic signaling.

Reward System

Limbic-hypothalamic circuitry reinforcing behaviors; includes nucleus accumbens and lateral hypothalamus.

Punishment System

Diffuse limbic network (amygdala, hippocampus, thalamus, etc.) producing aversive responses.

Amygdala

Temporal-lobe limbic nucleus key to fear, rage, aggression, and emotional memory; interacts with hypothalamus.

Hippocampus

Temporal-lobe limbic structure essential for forming and retrieving memories.

Cingulate Gyrus

Frontal-lobe cortical component of limbic system involved in emotion formation and processing.

Prefrontal Cortex

Frontal cortical area that integrates limbic input for decision making, social behavior, and emotion regulation.

Diabetes Insipidus

Condition of excessive urination and thirst caused by ADH deficiency, often from SON/PVN lesions.

Primitive Brain

Colloquial term for the limbic system emphasizing its evolutionary age and instinctive functions.