102 Glossary: The Endocrine System
GLOSSARY
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)
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
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
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
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
endocrine gland tissue or organ that secretes hormones into the blood and lymph without ducts such that they may be transported to organs distant from the site of secretion
endocrine system cells, tissues, and organs that secrete hormones as a primary or secondary function and play an integral role in normal bodily processes
epinephrine primary and most potent catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called adrenaline
estrogens class of predominantly female sex hormones important for the development and growth of the female reproductive tract, secondary sex characteristics, the female reproductive cycle, and the maintenance of pregnancy
exocrine system cells, tissues, and organs that secrete substances directly to target tissues via glandular ducts
general adaptation syndrome (GAS) the human body’s three-stage response pattern to short- and long-term stress
gigantism disorder in children caused when abnormally high levels of GH prompt excessive growth
glucagon pancreatic hormone that stimulates the catabolism of glycogen to glucose, thereby increasing blood glucose levels
glucocorticoids hormones produced by the zona fasciculata of the adrenal cortex that influence glucose metabolism
goiter enlargement of the thyroid gland either as a result of iodine deficiency or hyperthyroidism
gonadotropins hormones that regulate the function of the gonads
growth hormone (GH) anterior pituitary hormone that promotes tissue building and influences nutrient metabolism (also called somatotropin)
hormone secretion of an endocrine organ that travels via the bloodstream or lymphatics to induce a response in target cells or tissues in another part of the body
hyperglycemia abnormally high blood glucose levels
hyperparathyroidism disorder caused by overproduction of PTH that results in abnormally elevated blood calcium
hyperthyroidism clinically abnormal, elevated level of thyroid hormone in the blood; characterized by an increased metabolic rate, excess body heat, sweating, diarrhea, weight loss, and increased heart rate
hypoparathyroidism disorder caused by underproduction of PTH that results in abnormally low blood calcium
hypophyseal portal system network of blood vessels that enables hypothalamic hormones to travel into the anterior lobe of the pituitary without entering the systemic circulation
hypothalamus region of the diencephalon inferior to the thalamus that functions in neural and endocrine signaling
hypothyroidism clinically abnormal, low level of thyroid hormone in the blood; characterized by low metabolic rate, weight gain, cold extremities, constipation, and reduced mental activity
infundibulum stalk containing vasculature and neural tissue that connects the pituitary gland to the hypothalamus (also called the pituitary stalk)
inhibin hormone secreted by the male and female gonads that inhibits FSH production by the anterior pituitary
inositol triphosphate (IP3) molecule that initiates the release of calcium ions from intracellular stores
insulin pancreatic hormone that enhances the cellular uptake and utilization of glucose, thereby decreasing blood glucose levels
insulin-like growth factors (IGF) protein that enhances cellular proliferation, inhibits apoptosis, and stimulates the cellular uptake of amino acids for protein synthesis
luteinizing hormone (LH) anterior pituitary hormone that triggers ovulation and the production of ovarian hormones in females, and the production of testosterone in males
melatonin amino acid–derived hormone that is secreted in response to low light and causes drowsiness
mineralocorticoids hormones produced by the zona glomerulosa cells of the adrenal cortex that influence fluid and electrolyte balance
neonatal hypothyroidism condition characterized by cognitive deficits, short stature, and other signs and symptoms in people born to women who were iodine-deficient during pregnancy
norepinephrine secondary catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called noradrenaline
osmoreceptor hypothalamic sensory receptor that is stimulated by changes in solute concentration (osmotic pressure) in the blood
oxytocin hypothalamic hormone stored in the posterior pituitary gland and important in stimulating uterine contractions in labor, milk ejection during breastfeeding, and feelings of attachment (also produced in males)
pancreas organ with both exocrine and endocrine functions located posterior to the stomach that is important for digestion and the regulation of blood glucose
pancreatic islets specialized clusters of pancreatic cells that have endocrine functions; also called islets of Langerhans
parathyroid glands small, round glands embedded in the posterior thyroid gland that produce parathyroid hormone (PTH)
parathyroid hormone (PTH) peptide hormone produced and secreted by the parathyroid glands in response to low blood calcium levels
pineal gland endocrine gland that secretes melatonin, which is important in regulating the sleep-wake cycle
pinealocyte cell of the pineal gland that produces and secretes the hormone melatonin
pituitary dwarfism disorder in children caused when abnormally low levels of GH result in growth retardation
pituitary gland bean-sized organ suspended from the hypothalamus that produces, stores, and secretes hormones in response to hypothalamic stimulation (also called hypophysis)
PP cell minor cell type in the pancreas that secretes the hormone pancreatic polypeptide
progesterone predominantly female sex hormone important in regulating the female reproductive cycle and the maintenance of pregnancy
prolactin (PRL) anterior pituitary hormone that promotes development of the mammary glands and the production of breast milk
stage of exhaustion stage three of the general adaptation syndrome; the body’s long-term response to stress mediated by the hormones of the adrenal cortex
stage of resistance stage two of the general adaptation syndrome; the body’s continued response to stress after stage one diminishes
testosterone steroid hormone secreted by the male testes and important in the maturation of sperm cells, growth and development of the male reproductive system, and the development of male secondary sex characteristics
thyroxine (also, tetraiodothyronine, T4) amino acid–derived thyroid hormone that is more abundant but less potent than T3 and often converted to T3 by target cells
triiodothyronine (also, T3) amino acid–derived thyroid hormone that is less abundant but more potent than T4
zona fasciculata intermediate region of the adrenal cortex that produce hormones called glucocorticoids
zona glomerulosa most superficial region of the adrenal cortex, which produces the hormones collectively referred to as mineralocorticoids
zona reticularis deepest region of the adrenal cortex, which produces the steroid sex hormones called androgens