Final (New content) Flashcards
Thyroid hormones are derived from the amino acid ________
Tyrosine
True or False
T3 and T4 are hydrophilic
False - hydrophobic
Catecholamines bind to _______ _______ receptors and thyroid hormones bind to ________ ________
cell membrane; nuclear receptors
Which of the following describes catecholamines?
a) Amino acid derived thyroid hormone
b) Hydrophilic
c) Circulate unbound in the blood
d) all of the above
d) all of the above
Which of the following is true of thyroid glands?
a) Follicular cells synthesize the thyroid hormones
b) Multiple layers of epithelium
c) Absence of blood capillaries
d) all of the above
a) follicular cells synthesize the thyroid hormones
What is true of colloid?
a) Viscous rich protein
b) Rich in glycoprotein thyroglobulin
c) Main storage of active TH’s
d) all of the above
d) all of the above
What allows mammals to withstand iodine deprivation without effecting production of thyroid hormones?
a) Colloid storage
b) Secretion of calcitonin
c) Conversion of iodine to iodide
d) none of the above
a) Colloid storage
Colloid is found within the _____ and is created by _____ _____
lumen; glandular cells
What cells are responsible for calcitonin secretion?
a) C-cells or parafollicular cells
b) Follicular cells
c) Colloid
d) None of the above
a) C-cells or parafollicular cells
What is synthesized within the follicle epithelial cell and secreted into the colloid?
Thyroglobulin
What is the substrate that helps form thyroid hormones?
Tyrosine
True or False
Iodide is converted to iodine to be transported in the blood
False
Iodine is converted to iodide to be transported in the blood
Iodine (I2) comes from the ____ and is converted to ______ in the intestinal tract and is transported to the ______ _____ _____
Iodine comes from the diet and is converted to iodide in the intestinal tract and is transported to the thyroid follicle cells
What type of transport do thyroid follicle cells use to trap iodide?
Active transport (Na/I cotransporter)
What provides the driving force to bring Iodide into the cell?
Sodium - provides concentration gradient via Na/K ATP-ase
True or False
Iodide has highest concentration in the blood
False - higher concentration outside of the cell (25-200x higher)
What facilitates the synthesis of thyroid hormones?
a) Thyroxine
b) Thyroid peroxidase
c) Tyrosine
d) Iodothyronine deiodinase
b) Thyroid peroxidase
What are the two steps involved in thyroid synthesis?
a) Organification
b) Oxidation of iodide to iodine plus tyrosine iodination
c) Coupling of iodinated tyrosines
d) all of the above
d) all of the above
a and b are the same process
True or False
Only small amounts of T4 are produced by the thyroid gland
False
Small amount of T3!
What is the main source of T3?
a) Coupling of DIT and MIT
b) Deiodination of T4
c) T3 synthesized by the thyroid gland
d) Lysosomes
b) Deiodination of T4
Thyroid hormones are transported into plasma via what transport proteins?
a) Thyroxine-binding globulin and Albumin
b) Corticoglucoid binding globulin and albumin
c) Albumin and transcortin
d) none of the above
a) TBG and albumin
True or False
It is difficult to shift the equilibrium between free and bound hormone in the blood plasma due to the availability of receptors
False
Equilibrium is easily shifted because of physiological or pharmacological situations (ie. increase of estrogen during pregnancy)
Which of the following statements regarding hormone clearance is false?
a) Rate of removal of hormone from the blood can not be measured
b) The MCR interferes with hormone concentrations
c) MCR = rate of disappearance from plasma / concentration of hormone
d) The rate of removal can be measured
A is the false answer
Which of the following is not a method of clearance for T3 and T4?
a) Conjugation (formation of sulfates and gluconuronides)
b) Deiodinatio
c) Excretion by liver into bile
d) Excretion by kidney into urine
e) All of the above
e) All of the above
True or False
Thyroid hormones are the primary factors for the control of cellular metabolism
True
Which of the following statements about thyroid hormones are correct?
a) Bind to nuclear receptors and initiate transcription of mRNA
b) Increase the rate of ATP formation
c) Increase basal metabolic rate
d) All of the above
d) all of the above
Which of the following describes thyroid hormone effects on carbohydrate metabolism?
a) Facilitates the movement of glucose into fat and muscle tissues
b) Decreases lipolysis
c) Causes hypolipidemia
d) Decreases HR, blood flow and cardiac output
a) is the only correct statement
True or False
Thyroid hormones increase GI motility
True
If the thyroid is removed from an amphibian, what would be the effect on that animal’s growth?
a) Normal growth
b) It would not fully develop
c) It would develop but more slowly
d) It would develop but would be deformed
b) It would not fully develop
Where is the parathyroid gland typically located?
Usually at the poles of the 2 lobes of the thyroid glands
What species only have 1 pair of parathyroid glands?
Pigs and rats
What type of hormone is PTH?
a) Steroid
b) Protein/Peptide
c) Amine
d) None of the above
b) Protein/peptide hormone
What are the 2 types of parathyroid hormones?
Chief cells and Oxyphil cells
Which of the following is a correct statement?
a) Chief cells produce PTH and are the larger of the 2 parathyroid cells
b) Oxyphil cells produce PTH and are the larger of the 2 parathyroid cells
c) Chief cells produce PTH while Oxyphil cells have unknown function despite being larger
d) None of the statements are correct
c) Chief cells produce PTH while Oxyphil cells have unknown function depsite being larger
Parathyroid cells are very sensitive to decline in blood ______ ______
ionic calcium
What stimulates PTH release?
a) Decrease in iCa
b) Increase in iCa
c) Calcitriol release
d) Decrease in phosphate
a) Decrease in iCa
What is the main gland involved in Calcium and Phosphate metabolism?
a) Thyroid gland
b) Adrenal gland
c) Parathyroid gland
d) Adrenal medulla
c) parathyroid gland
Where is majority of Phosphate and calcium found?
a) Muscles
b) Heart
c) Bones
d) Intracellular
c) bones
What is the biologically active form of calcium?
a) Ionized calcium
b) Calcium bound to albumin
c) Calcitriol
d) Calcium in bones
a) iCa
What form is calcium in the bone?
a) iCa
b) Intracellular calcium
c) hydroxyapatite crystals
d) Calcidiol
c) hydroxyapatite crystals
50% of calcium is ______ and 40% is _______ to ______
50% of calcium is ionized and 40% is bound to proteins (albumin)
Which of the following is not a form of calcium?
a) iCa
b) Bound to protein
c) Combined with other anions
d) Combined with other cations
d) Combined with other cations
Which of the following is the most important pool for physiological control of calcium concentration in the blood?
a) Calcitriol
b) Calcidiol
c) iCa
d) All of the above
d) iCa
True or False
Increased intracellular calcium is indicative to increased cell activity
True
What hormones are involved in the regulation of calcium?
a) PTH
b) Active Vit D (Calcitriol)
c) Calcitonin
d) All of the above
e) None of the above
d) All of the above
True or False
PTH has direct effect on calcium metabolism in the GI tract and indirect effect in the bones and kidneys.
False
PTH has direct effect on bone and kidney metabolism of calcium, and indirect effect on GI (via Calcitriol)
Which of the following are correct statements regarding PTH direct effect on bones?
a) Promotes the transfer of iCa across the osteoblast-osteoclast membrane
b) Osteocytes pump iCa into ECF and eventually the blood
c) Binds to receptors on bone osteoblast cells and stimulates production of osteoclast-activating factor
d) all of the above are correct
d) all of the above are correct
What action releases iCa and PO4 into the blood?
a) Organification
b) Binding of PTH to osteoblast cells
c) Binding of PTH to osteoclast cells
d) Activation of oestoblasts
b) binding of PTH to osteoblast cells
True or False
Vit D must be transformed by liver and kidneys to become biologically activated
True
Which of the following statements are true?
a) Calcitonin increases calcium absorption in GI tract
b) Calcium enhances PTH effects on bone metabolism
c) PTH stimulates a kidney enzyme which converts calcidiol to calcitriol
d) All of the above are correct
c) PTH stimulates kidney enzyme which converts calcidiol to calcitriol
Explanation:
a) is not correct b/c CALCITRIOL increases calcium absorption
b) is not correct b/c PTH enhances effects of PTH on bone metabolism of calcium
What feature allows calcitriol to be carried in plasma by transcalciferin?
a) Hydrophobic
b) Hydrophilic
c) Lipophobic
d) None of the above
a) Hydrophobic
_______ stimulates the active transport of dietary calcium across the intestinal epithelium
Calcitriol
Which of the following explains how hindgut fermenters regulate blood calcium levels?
a) Intestinal mechanisms to absorb calcium at all times
b) Calcitriol stimulates active transport across the intestinal epithelium
c) Regulates blood Ca2+ by increasing/decreasing urinary loss
d) All of the above
e) None of the above
f) More than one of the above
f) More than one of the above - both A and C are correct
By regulating ______ animals can regulate ____ entering the blood from the diet
By regulating calcitriol animals can regulate iCa entering the blood from the diet
Increase in iCa _____ PTH secretion
Decrease in iCa _____ PTH secretion
Increase in iCa stimulates PTH
Decrease in iCa inhibits PTH
What is produced by parafollicular cells or c-cells in the thyroid gland?
a) Calcitriol
b) Calcium
c) Calcitonin
d) All of the above
c) Calcitonin
Increase in blood iCa stimulates ______ release
Calcitonin
True or False
Calcitonin release counterbalances the effects of PTH
True
True or False
Calcitonin increases the movement of calcium from the bone
False - it decreases the movement of calcium
Which of the following does NOT stimulate calcitonin secretion?
a) Gastrin
b) Secretin
c) CCK
d) Pepsinogen
d) Pepsinogen
Increased iCa ______ calcitonin secretion
Stimulates
What is the main factor regulating production and secretion of PTH and calcitonin?
a) Free calcium levels in the blood
b) Calcium in bones
c) Phosphate levels in blood
d) Phosphate levels in bone
a) Free calcium levels in the blood
Calcitonin ______ calcium levels while PTH _____ calcium levels
Calcitonin decreases calcium levels while PTH increases calcium levels
Which of the following is true in the case of Hyperparathyroidism?
a) Leads to persistent hypercalcemia
b) Negative feedback control is lost
c) Secretion of PTH is not suppressed
d) All of the above
d) All of the above
Which of the following are symptoms of hyperparathyroidism?
a) PU/PD
b) UTI
c) Tachycardia
d) all of the above
d) All of the above
What disease process correlates with hypocalcemia, hyperphosphatemia, and decreased calcitriol?
a) Hyperparathyroidism
b) Hypothyroidism
c) Hypoparathyroidism
d) Hyperthyroidism
c) Hypoparathyroidism
Where are adrenal glands located?
Next to the cranial pole of the kidneys
Which of the following are maintained by the adrenal gland?
a) Potassium
b) Sodium
c) Water
d) All of the above
d) All of the above
Which of the following is an action of the adrenal gland?
a) Regulate body’s response to stress
b) Control blood pressure
c) Is the site for steroidogenesis
d) All of the above
d) all of the above
Which of the following statements are correct?
a) Glucocorticoids are synthesized in the Zona glomerulosa
b) Estrogen and testosterone are synthesized in the Zona reticularis
c) Epinephrine and Norepinephrine are synthesized in the Zona fasciulata
d) All of the above are correct
b) Estrogen and testosterone are synthesized in the Zona reticularis
Where are catecholamines (epinephrine and NE) synthesized?
a) Adrenal cortex
b) Zona glomerulosa
c) Adrenal medulla
d) HPA axis
c) Adrenal medulla
Which of the following statements are false?
a) ACTH stimulates the Fascicular zone more strongly than the reticular and glomerulosa
b) ACTH stimulates the adrenal medulla more strongly than the cortex
c) ACTH stimulates the reticularis zone more strongly than the glomerulosa zone
d) Potassium and angiotensin stimulate the glomerular zone
b) is the incorrect statement
Where does the conversion of cholesterol to pregnenolone take place?
a) Cytosol
b) Nucleus
c) Mitochondria
d) Cell membrane
c) Mitochondria
What is the rate limiting step in steroidogenesis?
Conversion of cholesterol to pregnenolone, regulated by ACTH
True or False
Cholesterol is carried in the blood plasma by VLDL
False - LDL
Which of the following statements regarding steroidogenesis are correct?
a) Enters the cells via endocytosis
b) ACTH limits the rate of synthesis
c) Steroid hormones are secreted immediately by diffusion across the membrane
d) all of the above
d) All of the above are correct
True or False
Aldosterone is largely bound to transcortin for transport
False - Aldosterone is bound mostly to albumin, Cortisol is mostly bound to transcortin
Androgen hormones can bind to cell surface receptors triggering a rapid response via….
a) Nuclear receptors
b) Ligand gated channels
c) GPCR
d) All of the above
e) More than one of the above
e) More than one
b and c allow for more rapid response.
They do bind to nuclear receptors but that is much slower
True or False
Only unbound hormones can diffuse into the cell
True
What corticosteroids influence salt and water balance?
a) Glucocorticosteroids
b) Mineralocorticosteroids
c) Corticotropins
d) Catecholamines
b) Mineralocorticosteroids
What characteristics allows steroids to become more water-soluble for passage in the urine?
a) Lipophilic
b) Hydrophobic
c) Conjugation of sulfates and gluconuronides
C) Conjugation of sulfates and gluconuronides
What is the primary mineralocorticoid?
a) Androgens
b) Aldosterones
c) Catecholamines
d) Glucocorticoids
b) Aldosterone
True or False
ACTH has little effect in aldosterone synthesis
True
True or False
There are many receptors for ACTH located in the cells of the zona glomerulosa
False
There are FEW receptors for ACTH which is why it has little effect in aldosterone synthesis
Which of the following situations stimulate RAAS?
a) Hypertension
b) Hyponatremia
c) Hypokalemia
d) All of the above
b) Hyponatremia
RAAS is stimulated by hypotension and hyponatremia
Production of aldosterone is mainly regulated by what?
a) ACTH synthesis
b) RAAS
c) Blood pressure
d) All of the above
b) RAAS
What detects hyponatremia in renal filtrate?
a) Macula densa
b) Baroreceptors
c) B1 andrenoreceptors
d) RAAS
a) Macula densa
What detects reduced BP in the kidneys?
Baroreceptors in the afferent arteriole
Which of the following stimulate renin secretion?
a) Hyponatremia in renal filtrate
b) Reduced BP in kidneys
c) Sympathetic stimulation of juxtaglomerular apparatus
d) All of the above
d) All of the above
What are the effects of stimulation of renin secretion (RAAS)?
a) Increase in [Na+]
b) Increased water absorption
c) Increased blood pressure
d) All of the above
d) All of the above
If there is a decrease in renal perfusion (juxtraglomerular apparatus) what is the effect on renin?
a) Stimulates renin secretion
b) Inhibits renin secretion
c) Stimulates sodium channels to open
d) Increases the blood pressure of the kidneys
a) Stimulates renin secretion
Increase in concentration of potassium directly stimulates _________ ________ to secrete aldosterone
Zona glomerulosa
Aldosterone acts on ______ _____ of the kidneys to assist in active reabsorption of sodium
distal tubules
What is the result of aldosterone action on the kidney’s distal tubules?
a) Decreased Na and K reabsorption
b) Increased Na reabsorption and K secretion
c) Increased Na reabsorption and decreased K secretion
d) Increased Na reabsorption but no effect on K
b) Increased Na reabsorption and K secretion
Which of the following drive the action of Na and K within the distal tubules of the kidney?
a) GPCR
b) Simple diffusion
c) Na/K ATP-ase
d) Ligand gated channels
c) Na/K ATP-ase
What is true of aldosterone?
a) Hormone-receptor complex initiates transcription in the nucleus resulting in new protein channels/pumps
b) Aldosterone induced proteins modify existing proteins
c) Aldosterone combines with cytoplasmic receptor
d) All of the above
d) All of the above
True/False
PTH increases reabsorption of calcium via distal convoluted tubules, and decreases renal reabsorption of phosphate via Proximal convoluted tubules
True
