Hypothalamus and Pituitary Function

Vocabulary flashcards covering the functional anatomy of the hypothalamus, anterior and posterior pituitary connections, hypothalamic releasing and inhibiting hormones, clinical classification of endocrine disorders, and consequences of pituitary stalk transection.

Hypothalamo-Hypophyseal Portal System

A vascular network wherein hypothalamic releasing hormones diffuse into primary capillaries at the median eminence, travel through portal venules down the pituitary stalk, and enter secondary capillaries in the anterior pituitary to stimulate hormone release.

Hypothalamo-Hypophyseal Tract

The axonal pathway through which neurohormones (ADH and oxytocin) synthesized in hypothalamic nuclei are transported inside secretory granules to the posterior pituitary for storage and release.

Supraoptic and Paraventricular Nuclei (SON and PVN)

Hypothalamic neuronal nuclei whose cell bodies synthesize antidiuretic hormone (ADH) and oxytocin.

Posterior Pituitary

The storage and release site for antidiuretic hormone (ADH) and oxytocin produced by hypothalamic neurons in the supraoptic and paraventricular nuclei.

Corticotropin-Releasing Hormone (CRH)

A hypothalamic releasing hormone that stimulates the anterior pituitary to secrete adrenocorticotropic hormone (ACTH), targeting the adrenal cortex.

Thyrotropin-Releasing Hormone (TRH)

A hypothalamic releasing hormone that stimulates the anterior pituitary to secrete thyroid-stimulating hormone (TSH), targeting the thyroid gland.

Gonadotropin-Releasing Hormone (GnRH)

A hypothalamic releasing hormone that stimulates the anterior pituitary to release the gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone (LH), targeting the ovaries and testes.

Growth Hormone-Releasing Hormone (GHRH)

The hypothalamic hormone that serves as the main regulator stimulating the anterior pituitary to secrete growth hormone (GH), which produces generalized effects on bone, muscle, and adipose tissue.

Somatostatin (GHIH)

Growth hormone-inhibiting hormone; a hypothalamic neurohormone that inhibits the release of growth hormone from the anterior pituitary.

Prolactin-Inhibiting Hormone (PRIH / Dopamine)

A hypothalamic factor (dopamine) that provides tonic inhibition of prolactin secretion from the anterior pituitary.

Primary Hormonal Disorder

An endocrine disorder caused by a defect residing directly in the peripheral target gland from which the hormone originates.

Secondary Hormonal Disorder

An endocrine disorder caused by a defect located in the anterior pituitary gland.

Tertiary Hormonal Disorder

An endocrine disorder caused by a defect located in the hypothalamus.

Pituitary Stalk Damage

A neurovascular disruption between the hypothalamus and pituitary that causes a decrease in all anterior pituitary hormones EXCEPT prolactin, which increases due to the loss of hypothalamic dopamine inhibition.

Galactorrhea in Hypothalamic Dysfunction

Inappropriate milk secretion resulting from a defect in the hypothalamus preventing dopamine from reaching the anterior pituitary to inhibit prolactin.