11.8 Control Systems Involving the Hypothalamus and Pituitary Gland

Adrenocorticotropic Hormone (ACTH)

Polypeptide hormone secreted by anterior pituitary gland; stimulates adrenal cortex to secrete cortisol; also called corticotropin

Anterior Pituitary Gland

Anterior portion of pituitary gland; synthesizes, stores, and releases ACTH, GH, TSH, PRL, FSH, and LH

Beta-Endorphin

Putative hormone released from the anterior pituitary gland, believed to play a role in adaptation to stress and pain relief; also acts as a neurotransmitter

Beta-Lipotropin

A protein formed from the proopiomelanocortin precursor in the anterior pituitary gland; further processing results in the putative hormone beta-endorphin

Corticotropin-Releasing Hormone (CRH)

Hypophysiotropic peptide hormone that simulates ACTH (corticotropin) secretion by anterior pituitary gland

Follicle-Stimulating Hormone (FSH)

Glycoprotein hormone secreted by anterior pituitary gland in males and females that acts on gonads; a gonadotropin

Gonadotropic Hormones

Glycoprotein hormones secreted by anterior pituitary gland (LH, FSH) and placenta (hCG) that influence gonadal function

Gonadotropin-Releasing Hormone (GnRH)

Hypophysiotropic hormone that simulates LH and FSH secretion by anterior pituitary gland in males and females

Growth Hormone (GH)

Peptide hormone secreted by anterior pituitary gland; stimulates insulin-like growth factor 1 release through which it enhances body growth by stimulating protein synthesis

Growth Hormone-Releasing Hormone (GHRH)

Hypothalamic peptide hormone that stimulates growth hormone secretion by anterior pituitary gland

Hypophysiotropic Hormones

Hormones secreted by hypothalamus that control secretion of an anterior pituitary gland hormone

Hypothalamo-Hypophyseal Portal Vessels

Small veins that link the capillaries of the median eminence at the base of the hypothalamus to capillaries that bathe the cells of the anterior pituitary gland; neurohormones are secreted from the hypothalamus into these vessels

Hypothalamus

Brain region below thalamus; responsible for integration of many basic neural, endocrine, and behavioral functions, especially those concerned with regulation of internal environment

Infundibulum

The stalk of tissue connecting the median eminence at the base of the hypothalamus with the pituitary gland

Insulin-Like Growth Factor-1 (IGF-1)

Hormone that mediates mitosis-stimulating effect of growth hormone on bone and other tissues and has feedback effects on hypothalamus and anterior pituitary gland

Long-Loop Negative Feedback

Inhibition of anterior pituitary gland and/or hypothalamus by hormone secreted by third endocrine gland in a sequence

Luteinizing Hormone (LH)

Glycoprotein gonadotropic hormone secreted by anterior pituitary gland; rapid increase in females at midmenstrual cycle initiates ovulation; stimulates Leydig cells in males

Median Eminence

Region at base of hypothalamus containing capillary tufts into which hypophysiotropic hormones are secreted

Oxytocin

Peptide hormone synthesized in hypothalamus and released from posterior pituitary; stimulates mammary glands to release milk and uterus to contract

Pituitary Gland

Endocrine gland that lies in bony pocket below hypothalamus; constitutes anterior pituitary gland and posterior pituitary gland

Posterior Pituitary

Portion of pituitary gland from which oxytocin and vasopressin are released

Prolactin

Polypeptide hormone secreted by anterior pituitary gland; stimulates milk synthesis by mammary glands

Short-Loop Negative Feedback

Inhibition of hypothalamus by an anterior pituitary gland hormone

Somatostatin (SST)

Hypophysiotropic hormone that inhibits growth hormone secretion by anterior pituitary gland; also found in stomach and pancreatic islets

Thyroid-Stimulating Hormone (TSH)

Glycoprotein hormone secreted by anterior pituitary gland; induces secretion of thyroid hormone; also called thyrotropin

Thyrotropin-Releasing Hormone (TRH)

Hypophysiotropic hormone that stimulates thyrotropin and prolactin secretion by anterior pituitary gland

Vasopressin (Antidiuretic Hormone (ADH))

Peptide hormone synthesized in hypothalamus and released from posterior pituitary gland; increases water permeability of kidneys’ collecting ducts and causes vasoconstriction