Key Terms
acromegaly
disorder in adults caused when abnormally high levels of GH trigger growth of bones in the face, hands, and feet
adenylyl cyclase
membrane-bound enzyme that converts ATP to cyclic AMP, creating cAMP, as a result of G-protein activation
adrenal cortex
outer region of the adrenal glands consisting of multiple layers of epithelial cells and capillary networks that produces mineralocorticoids and glucocorticoids
adrenal glands
endocrine glands located at the top of each kidney that are important for the regulation of the stress response, blood pressure and blood volume, water homeostasis, and electrolyte levels
adrenal medulla
inner layer of the adrenal glands that plays an important role in the stress response by producing epinephrine and norepinephrine
adrenocorticotropic hormone (ACTH)
anterior pituitary hormone that stimulates the adrenal cortex to secrete corticosteroid hormones (also called corticotropin)
alarm reaction
the short-term stress, or the fight-or-flight response, of stage one of the general adaptation syndrome mediated by the hormones epinephrine and norepinephrine
aldosterone
hormone produced and secreted by the adrenal cortex that stimulates sodium and fluid retention and increases blood volume and blood pressure
alpha cell
pancreatic islet cell type that produces the hormone glucagon
angiotensin-converting enzyme
the enzyme that converts angiotensin I to angiotensin II
antidiuretic hormone (ADH)
hypothalamic hormone that is stored by the posterior pituitary and that signals the kidneys to reabsorb water
atrial natriuretic peptide (ANP)
peptide hormone produced by the walls of the atria in response to high blood pressure, blood volume, or blood sodium that reduces the reabsorption of sodium and water in the kidneys and promotes vasodilation
autocrine
chemical signal that elicits a response in the same cell that secreted it
beta cell
pancreatic islet cell type that produces the hormone insulin
calcitonin
peptide hormone produced and secreted by the parafollicular cells (C cells) of the thyroid gland that functions to decrease blood calcium levels
chromaffin
neuroendocrine cells of the adrenal medulla
colloid
viscous fluid in the central cavity of thyroid follicles, containing the glycoprotein thyroglobulin
cortisol
glucocorticoid important in gluconeogenesis, the catabolism of glycogen, and downregulation of the immune system
cyclic adenosine monophosphate (cAMP)
second messenger that, in response to adenylyl cyclase activation, triggers a phosphorylation cascade
delta cell
minor cell type in the pancreas that secretes the hormone somatostatin
diabetes mellitus
condition caused by destruction or dysfunction of the beta cells of the pancreas or cellular resistance to insulin that results in abnormally high blood glucose levels
diacylglycerol (DAG)
molecule that, like cAMP, activates protein kinases, thereby initiating a phosphorylation cascade
downregulation
decrease in the number of hormone receptors, typically