adrenal gland
endocrine organ located atop each kidney that responds to stress and low blood glucose levels
adrenocorticotropin (ACTH)
pituitary hormone that stimulates the adrenal glands to produce cortisol in response to stress and low blood sugar
aldosterone
adrenal hormone that acts on the kidneys to increase sodium and water retention and blood volume in order to regulate blood pressure
androgen
hormone responsible for the development of male sex organs and the maintenance of secondary male characteristics
calcitonin
decreases the activity of osteoclasts, the cells in bones responsible for the breakdown of bone tissue to release calcium into the blood
catecholamine
class of water-soluble hormone produced by the adrenal medulla in response to stressful situations.
cortisol
hormone produced by the adrenal cortex in response to stress and low blood sugar that increases blood sugar levels and suppresses the inflammatory response
endocrine gland
secretes internal chemical messengers (hormones) that travel through the body to act on target cells
epinephrine
catecholamine hormone produced by the adrenal medulla that acts on alpha, beta-1, beta-2, and beta-3 receptors
follicle cavity
fluid-filled, iodine-rich cavity in the thyroid surrounded by a single layer of follicular cells, in which the hormones T3 and T4 are produced
follicle-stimulating hormone (FSH)
secreted from the anterior pituitary, stimulates the growth of ovarian follicles in women; in men, it acts on testicular Sertoli cells to stimulate sperm production (spermatogenesis)
glucagon
pancreatic hormone that increases blood sugar by triggering glycogen breakdown in the liver
homeostasis
state of equilibrium in a system used to maintain a consistent internal environment in the body
hormone
chemical messenger of the body that is secreted by endocrine glands
hypothalamus
brain structure responsible for maintaining homeostasis. It connects the endocrine and nervous systems.
insulin
pancreatic hormone that decreases blood sugar by increasing the rate of glucose uptake in cells throughout the body
islet of Langerhans
specialized cluster of endocrine cells located along the length of the pancreas that produces the hormones glucagon and insulin
luteinizing hormone (LH)
secreted from the anterior pituitary. In women it triggers ovulation and corpus luteal development; in men it stimulates testicular interstitial cells to produce and secrete testosterone.
melatonin
pineal hormone that regulates circadian rhythms; its production increases in the dark
norepinephrine
catecholamine hormone produced by the adrenal medulla that acts mainly on alpha receptors
oxytocin
pituitary hormone involved in several processes including the stimulation of breast milk production and the stimulation of uterine contractions during childbirth
pancreas
elongated glandular organ of the digestive system that regulates blood glucose levels
parathyroid
gland located behind each lobe of the thyroid that regulates calcium levels
parathyroid hormone (PTH)
stimulates osteoclasts to increase the levels of calcium in the blood
pineal gland
brain structure that controls circadian rhythms, or day-night cycles
pituitary
brain structure that functions in close association with the hypothalamus to regulate other parts of the endocrine system.
thyroid
butterfly-shaped gland located in the front of the neck that regulates the body's metabolism
thyroxine (T4)
thyroid hormone containing four iodine ions that targets cells in the body to increase the metabolic rate
triiodothyronine (T3)
thyroid hormone containing three iodine ions that targets cells in the body to increase the metabolic rate
vasopressin
hormone that is produced by the hypothalamus and released from the posterior pituitary gland that acts on the kidneys and increases the amount of water reabsorbed back into the bloodstream