Chapter 10: The Endocrine system Flashcards
(100 cards)
1
Q
Hormones vs. Neurotransmitters
A
hormones in blood; neurotransmitters in synapses epinephrine can be either
2
Q
hormones
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chemical messengers that are released in one tissue and transported by the bloodstream to reach target cells in other tissues
3
Q
amino acid derivative hormones
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small molecules structurally similar to amino acids: epinephrine, norepinephrine, thyroid hormones, melatonin
4
Q
peptide hormones
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chains of amino acids; largest class of hormones all hypothalamic, pituitary gland, heart, kidney, thymus, digestive, and pancreatic hormones, poterior pituitary (ADH, oxytocin)
5
Q
lipid derivative hormones
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two classes: steroids, aldosterone and eicosanoids (prostaglandins)
6
Q
steroid hormones
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insoluble in water, bind to specific transport proteins in the blood; lipid-soluble released by the reproductive organs and the adrenal glands
7
Q
Eicosanoids
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fatty acid-based compounds derived from 20-carbon fatty acid arachidonic acid; coordinate local cellular activities, affect enzymatic processes in extracellular fluids, including blood clotting; lipid-soluble include prostaglandins
8
Q
g protein
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an enzyme complex coupled to a membrane receptor
9
Q
cyclic-AMP
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most common second messenger; created by an enzyme called adenylate cyclase; activates kinase enzymes which attach high-energy phosphate group to another molecule
10
Q
phosphorylation
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The metabolic process of introducing a phosphate group into an organic molecule
11
Q
adenylate cyclase
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converts ATP to cAMP
12
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kinase
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enzyme that transfers phosphate ions from one molecule to another; activated by cAMP
13
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phosphodiesterase (PDE)
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breaks down cAMP
14
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first messenger
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A water soluble hormone that binds to its receptor at the outer surface of the plasma membrane because it cannot pass through cell membrane
15
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Second messenger
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acts as a signal molecule in the cytoplasmexamples include: cAMP, calcium ions, cyclic-GMP
16
Q
methods of free hormone activation
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- diffusing out of bloodstream/binding to target cells2. absorbed/broken down by liver or kidney3. broken down by enzymes in blood or interstitial fluids
17
Q
regulatory hormones
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Control release of hormones from anterior pituitary; may be releasing (RH) or inhibitory (IH)
18
Q
posterior pituitary gland
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releases ADH and oxytocin
19
Q
anterior pituitary gland
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releases TSH, ACTH, FSH, LH, PRL, GH, and MSH
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hypophysis
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pituitary gland
21
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infundibulum
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connects hypothalamus to pituitary gland
22
Q
hypophyseal portal system
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blood leaving capillary beds in hypothalamus travels to a capillary bed in anterior pituitary to allow for secretion of releasing hormones
23
Q
tropic hormones
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regulatory hormones
24
Q
thyroid-stimulating hormone (TSH)
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“thyrotropin”targets thyroid gland; released in response to thyrotropin-releasing hormone (TRH) from hypothalamusresults in secretion of thyroid hormones
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adrenocorticotropic hormone (ACTH)
targets adrenal cortex; released in response to corticotropin-releasing hormone (CRH) from hypothalamusresults in glucocorticoid secretion
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gonadotropins
FSH and LH released in response to gonadotropin-releasing hormone (GnRH) from hypothalamus regulates the activities of the male and female sex organs, or gonads
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follicle-stimulating hormone (FSH)
targets follicle cells of ovaries, sustentacular cells of testes; released in response to GnRH; inhibited by inhibitinresults in estrogen secretion, egg follicle development, sperm maturation
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luteinizing hormone (LH)
targets gonads; released in response to GnRHresults in ovulation, progesterone and esterone secretion, testosterone secretion
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inhibin
inhibits secretion of FSH
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prolactin (PRL)
targets mammary glands; released in response to prolactin-releasing hormone (PRH)results in production of milk
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growth hormone (GH)
"human growth hormone (hGH)"targets all cells; released in response to GH-RHresults in growth, protein synthesis, lipid mobilization/catabolism; glucose-sparing effect
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somatotropin
hGH
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melanocyte-stimulating hormone (MSH)
targets melanocytes; virtually non-functional in humans except during fetal development, in very young children, in pregnancy, and in some diseasesresults in increased melanin synthesis
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somatomedins
"insulin-like growth factors"peptide hormones that bind to receptor sites on a variety of cell membranes, increase the rates at which amino acids are incorporated into new proteins
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glucose-sparing effect
causes tissues to use fatty acids instead of glucose as an energy sourceaccelerate rates of glucose synthesis/glycogen formation, releases fatty acids from adipose tissue into bloodstream; tissues break down fatty acids rather than glucose
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antidiuretic hormone (ADH)
manufactured in hypothalamus, released by posterior pituitary gland, targets kidneysresults in reabsorption/conservation of water, elevation of blood volume/pressure, vasoconstrictionreleased in response to increased osmotic pressure or low blood volume
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oxytocin
manufactured in hypothalamus, released by posterior pituitary gland, targets reproductive organsresults in smooth muscle uterine labor contractions, milk ejection, peaks during sexual activity
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vasopressin
ADH; decreases water lost at kidneys and causes vasoconstriction
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diabetes insipidus
posterior pituitary gland no longer releases adequate amounts of ADH or the kidney is resistant to its effect; water conservation is impaired; leads to polydipsia and polyuria
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isthmus
connects the two lobes of the thyroid gland
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colloid
viscous fluid containing large amounts of suspended proteins, hormones
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thyroxine
"tetraiodothyronine" or "t4"produced and secreted by follicle cells in the thyroid gland; targets all cells in the body, readily passes through cell membranes, increases overall body metabolismmakes up 90% of thyroid secretions
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Triiodothyronine
"t3"more potent than t4; only contains 3 iodine atoms
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calorigenic effect
cells consume more energy (specifically when stimulated by thyroid hormones)
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goiter
enlarged thyroid gland
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c cells
"parafollicular cells"endocrine cells sandwiched between follicle cells and basement membrane in thyroid glandproduce calcitonin (CT) in response to increase in blood calcium levels
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calcitonin
produced by c cells in thyroid gland; targets bones and kidneysinhibits osteoclasts (slowing release of calcium from the bone) and promotes calcium excretion at kidneys
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hyperthyroidism
presence of excess thyroid hormones in the blood; characterized by weight loss, heat intolerance, insomnia, muscle weakness, tachycardia
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thyrotoxic crisis
"thyroid storm"condition that reflects prolonged exposure of body organs to excess thyroid hormones, with resultant changes in structures and functionfrequently caused by Graves' disease
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hypothyroidism
inadequate amounts of thyroid hormones in the blood; characterized by weight gain, cold intolerance, depression, muscle cramps, bradycardia
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myxedema
condition that reflects long-term exposure to inadequate levels of thyroid hormonesclassic appearance is unemotional, puffy face, pale individual with thinned hair, enlarged tongue, cool skin
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Graves disease
excess circulating thyroid hormones; can lead to thyrotoxic crisisgenetic predisposition; autoimmune originshows signs of hyperthyroidism, along with potential protrusion of eyeballs and cardiovascular issues
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thyroid follicles
produce T3/T4 respond to thyroid-stimulating hormone
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chief cells
produce PTH
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parathyroid hormone (PTH)
"parathormone"targets bone and kidneys, stimulates osteoclasts, inhibits osteoblasts, reduces urinary excretion of calcium, stimulates secretion of calcitriolopposes calcitonin
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calcitriol
secreted by kidneys in response to PTHpromotes absorption of calcium and phosphate by the digestive tractsynthesis is dependent on D3
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suprarenal gland
adrenal gland; consists of adrenal cortex and medulla
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adrenal cortex
releases corticosteroids which are bound to transport proteins in the bloodstreamouter zone produces mineralocorticoids; middle zone produces glucocorticoids; inner zone produces androgens
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mineralocorticoids
affect the electrolyte composition of body fluids aldosterone
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aldosterone
principal mineralocorticoid; produced in adrenal cortextargets kidneys; acts on them to retain Na+ and excrete K+; raises blood pressure and normalizes electrolyte levels targets kidneys; release occurs in response to drop in blood sodium, volume, pressure, rise in blood potassium, or in response to angiotensin II
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glucocorticoids
produced in adrenal cortex, affect glucose metabolismcortisol, corticosterone, cortisoneglucose-sparing effects, anti-inflammatory, slow wound healing and suppress immune functions
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androgens
sex hormones
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cushing's disease
hyperadrenalism"moonface", skin changes, easy bruising, weight gain
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addison's disease
adrenal insufficiencyover 90% of cases are autoimmuneweakness, weight loss, hyperpigmentation
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adrenal medulla
secretes epinephrine (75-80%) and norepinephrineincreased cardiac activity, BP, glycogen breakdown, blood glucose levels
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pineal gland
secretes melatonininhibits reproductive function, acts as antioxidant, establishes day-night cycles
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pancreas
glucagon, insulin
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alpha cells
produce glucagon
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beta cells
secrete insulin; insulin leads to lower blood sugar which causes increase in glycogen within cells
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insulin
lowers blood sugar
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glucagon
increases blood glucose levels; opposes insulin
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kidneys
release calcitriol, erythropoietin, renin
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Eythropoietin (EPO)
released by kidneys in response to low blood volume or low oxygen levelsstimulates production of RBC in bone marrow
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renin
hormone secreted by the kidney in response to decline in blood volume/pressurestarts chain reaction (renin-angiotensin system) that leads to formation of angiotensin II
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angiotensin II
stimulates production of aldosterone and ADH, stimulates thirst, in Na+ reabsorption to increase fluid retention at vessels
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Atrial natriuretic peptide (ANP)
hormone secreted from atrial cells of the heart in response to atrial stretching and an increase in circulating blood volume; a diuretic that causes sodium loss and inhibits the thirst mechanism
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thymosins
produced in thymus; play a key role in the development and maintenance of normal immune functions
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testosterone
male sex hormone; promotes production of sperm, maintains the secretory glands of male reproductive tract, determines secondary sex characteristics, stimulates protein synthesis, growth, behavioral aggression
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sustentacular cells
support formation of functional sperm; secrete inhibin
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estrogens
steroid hormones that support the maturation of the eggs and stimulate the growth of the lining of the uterus
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corpus luteum
Endocrine tissue which produces estrogen and progesterone after ovulation
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progesterone
accelerates movement of fertilized eggs along uterine tubes, prepares uterus for arrival of developing embryo, causes enlargement of mammary glands
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leptin
negative feedback control of appetite, enhances GnRH and gonadotropin synthesis
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resistin
resists insulin sensitivity
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antagonistic effects
opposinginsulin/glucagon
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synergistic effect
additive effects, where net result is greater than effect of each alone would have beenglucose-sparing action of GH and glucocortisoids
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permissive effect
one hormone must be present to let another work
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integrative effects
different but complementary effectscalcitriol/PTH
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General Adaptation Syndrome (GAS)
stress responsethree phases: alarm, resistance, exhaustion
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alarm phase
immediate stress response; sympathetic nervous system "fight or flight"; epinephrine
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resistance phase
longer than a few hours; glucocorticoids dominate; some GH, epinephrine, TH; high metabolic demand
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exhaustion phase
system overload; occurs after extended resistance from mineral imbalances
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acromelagy
a disorder resulting from excessive secretion of growth hormone after puberty
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insulin shock
hypoglycemia
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common endocrine disorders in elderly
diabetes, hypothyroidism
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endocrine vs exocrine
Endocrine secretes hormones directly into bloodstream; exocrine secretes into a duct
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hypothalamus
link between nervous and endocrine systemssynthesizes ADH, oxytocin and 5 releasing hormones (thyrotropin-releasing, corticotropin-releasing, gonadotropin-releasing, and growth hormone-releasing)
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endocrine emergencies
generally the result of over or under-production of hormones
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Islets of Langerhans
located in the pancreas, contain alpha and beta cells
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Angiotensin-converting enzyme (ACE) inhibitors
Converts angiotensin I into angiotensin II (active form) to then go to adrenals and secrete aldosterone (cortex)
