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32 Cards in this Set
- Front
- Back
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What are some glands that synthesize and secrete hormones?
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pituitary, hypothalamus, thyroid, parathyroids, pineal, kidneys, adrenals, pancreas, testes, ovaries, gastrointestinal glands, heart, thymus
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In response to stress, what hormone is released by the anterior pituitary to stimulate the adrenal cortex to produce corticosteroids?
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adrenocorticotropic hormone (ACTH)
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The adrenal cortex release what kinds of hormones in response to stress?
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corticosteroids
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What kinds of corticosteroids are released by the adrenal cortex?
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glucocorticoids (cortisol & cortisone), mineralcorticoids (aldosterone), and cortical sex hormones (androgens)
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What kinds of hormones are released by the adrenal medulla?
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catecholamines: epinephrine (adrenaline) and norepinephrine (noradrenaline)
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What do the glucocorticoids such as cortisol and cortisone regulate?
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glucose regulation and protein metabolism. raise blood glucose levels by promoting protein breakdown and gluconeogensis and decreasing protein synthesis. antagonistic to the effects of insulin.
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What does the mineralcorticoid aldosterone regulate?
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plasma levels of sodium and potassium and, consequently, total extracellular water volume. Causes active reabsorption of sodium and passive reabsorption of water in the nephron. Results in both blood volume and blood pressure. Excess production of aldosterone results in retention of water with resulting hypertension.
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What stimulates the mineralcorticoids? What inhibits them?
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angiotensin II; ANP
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What gland secretes epinephrine and norepinephrine and what are their functions?
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the adrenal medulla; epinephrine increases the conversion of glycogen to glucose in liver and muscle tissue, causing an inc in blood glucose levels and an inc in the basal metabolic rate. both inc rate and strength of heartbeat and dilate and constrict blood vessels in a way as to inc blood supply to skeletal muscles, heart, and brain while dec blood supply to kidneys, skin and digestive tract.Both also promote release of lipids by adipose tissue. effects known as "flight or fight response" and are elicited by the SNS in response to stress. inhibit digestion. both are also neurotransmitters
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The anterior pituitary synthesizes both direct hormones and tropic hormones (which stimulate other endocrine glands to release hormones). Give examples of each.
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Direct hormones: growth hormone (GH)= promotes bone and muscle growth (dwarfism/gigantism in children, acromegaly in adults) and Prolactin= stimulates milk production and secretion
Tropic hormones: adrenocorticotropic hormone (ACTH)= stimulates adrenal cortex to release glucocorticoids and is regulated by the releasing hormone corticotrophin-releasing factor (CRF); thyroid-stimulating hormone (TSF) stimulates thyroid gland to synthesize and release thyroid hormones; Luteinizing hormone (LH)= stimulates ovulation and formation of corpus luteum and regulates progesterone secretion in women, in men stimulates interstitial cells of testes to synthesize testosterone; Follicle-stimulationg hormone (FSH)= maturation of ovarian follicles that begin secreting estrogen, in men, stimulates maturation of seminiferous tubules and sperm production; Melanocyte-stimulating hormone (MSH)= secreted by intermediate lobe of pituitary, function unclear in mammals but in frogs causes darkening of skin; endorphins= neurotransmitters that have pain-relieving properties |
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Describe the relationship between the posterior pituitary and the hypothalamus.
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posterior pituitary doesn't synthesize hormones; it stores and releases the peptide hormones oxytocin and ADH, which are produced by the neurosecretory cells of the hypothalamus.
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What is the function of oxytocin?
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released during childbirth; increases strength and frequency of uterine muscle contractions. also induced by suckling; stimulates milk secretion
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What is the function of antidiuretic hormone (ADH)?
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increases the permeability of the nephron's collecting duct to water, thereby promoting water reabsorption and inc blood volume (inc b.p.). is secreted when plasma osmolarity increases, as sensed by hypothalamus, or when blood volume decreases
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GnRH released by the hypothalamus stimulates the anterior pituitary to secrete ___ and ___.
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FSH; LH
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Neurosecretory cells in the hypothalamus synthesize ______ and _____ and transport them to the __________ for storage and secretion.
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oxytocin; ADH; posterior pituitary
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What is the importance of thyroid hormones in children and adults?
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children: growth and development
adults: maintenance of metabolic stability |
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What happens in hypothyroidism?
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slowed heart rate and respiratory rate, fatigue, cold intolerance and weight gain. (think of possible effects of dec metabolism). Hypothyroidism in newborns is called cretinism and is characterized by mental retardation and short stature.
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What happens in hyperthyroidism?
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inc metabolic rate, excessive warmth, profuse sweating, palpitations, weight loss, and protruding eyes
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What hormones does the thyroid gland secrete?
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thyroid hormones [thyroxine (T4) and triiodothyronine (T5)] and calcitonin
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What role does calcitonin play?
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decreases plasma Ca2+ concentration by inhibiting release of Ca2+ from bone; secretion regulated by plasma Ca2+ levels; antagonistic to the parathyroid hormone
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What is the pancreas's exocrine function?
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cells that secrete digestive enzymes into the small intestine via a series of ducts
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What is the pancreas's endocrine function?
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performed by islets of Langerhans which are composed of alpha and beta cells. alpha cells produce and secrete glucagon; beta cells produce and secrete insulin
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What role does glucagon (secreted by alpha cells of the pancreas) play?
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stimulates protein and fat degradation, the conversion of glycogen to glucose, and gluconeogenesis to inc blood glucose levels; antagonistic to insulin
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What role does insulin (secreted by beta cells of the pancreas) play?
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secreted in response to high blood glucose concentration; stimulates uptake of glucose by muscle and adipose cells and the storage of glucose as glycogen in muscle and liver cells, thus lowering blood glucose levels. also stimulates synthesis of fats from glucose and uptake of a.a.; actions are antagonistic to those of glucagon and the glucocorticoids.
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What is diabetes mellitus? What causes it?
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hyperglycemia (high blood glucose levels); caused by underproduction of insulin or an insensitivity to insulin
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What do the parathyroid glands synthesize and secrete?
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parathyroid hormone (PTH), which increases plasma [Ca2+] by stimulating the release of calcium from bone and decreasing calcium excretion in the kidneys
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When blood volume falls, the kidneys produces ______ and _____.
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renin (an enzyme that converts plasma protein angiotensionogen to angiotensin I, which is then converted to angiotensin II. this stimulates the adrenal cortex to secrete aldosterone which helps to restore blood volume by increasing sodium reabsorption (and hence water reabsorption in the kidney) and erythropoietin (EPO) (stimulates RBC production).
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Ingested food stimulates the stomach to release the hormone ________.
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gastrin- stimulates glands to release HCl
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When acidic food material enters from the stomach, the small intestine secretes _______, which neutralizes the acidity of the chyme.
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secretin
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___________ is released by the small intestine in the presence of fats and causes contraction of the gallbladder and release of bile into the small intestine.
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cholecystokinin
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What hormone does the pineal gland secrete?
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melatonin; role unclear, but believed to play a role in regulation of circadian rhythms; in primitive vertebrates, it lightens skin (antagonistic to MSH)
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Phototropism and geotropism in plants is associated with the hormones _______.
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auxins. phototropism: light reduces auxin supply; low concentration of auxin= slower growth, so shaded side grows faster and hence toward light. geotropism: negative geotropism causes shoots to grow upward; gravity increases the concentration of auxin on lower side whereas concentration on upper side decreases. cells on lower side grow faster causing vertical growth.
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