Adrenal Glands Flashcards
Remnant of the adrenal medulla present outside the adrenal gland usually at the bifurcation of the aorta
Organ of Zuckerkandl
The type of hormone that was determined to be the physiologic link between the adrenal cortex and medulla
Glucocorticoid hormone
The function of catecholamines is potentiated by which hormones?
Glucocorticoids
Catecholamines are metabolized by the action of two enzymes:
catechol-O-methyltransferase
monoamine oxidase.
What are the metabolites for Epinephrine and Norepinephrine?
Metanephrine and Normetanephrine
The primary end product of catecholamine metabolism
Vanillyl mandelic acid
enzyme: monoamine oxidase
Which catecholamine metabolite can be found in urine with pheochromocytoma?
Vanillyl mandelic acid
The rate-limiting enzyme in the synthesis of catecholamines:
Tyrosine hydoxylase
Hormone that stimulates the conversion of NE to EPI
Cortisol
The fight or flight reaction is mainly produced by:
Epinephrine
80% of normetanephrine is found in the:
CSF
The final product of catecholamines in the CNS
3-methoxy-4hydroxyphenyl glycol
Which catecholamine is produced by blood vessels?
Norepinephrine
Catecholamine receptor of the heart: A. α B. α2 C. β1 D. β2 E. β3
C. β1
Catecholamine receptor in veins, lymphatics and splanchnic arterioles: A. α B. α2 C. β1 D. β2 E. β3
A. α
Catecholamine receptors in skeletal muscle arterioles: A. α B. α2 C. β1 D. β2 E. β3
D. β2
Catecholamine receptor in pancreatic β cells: A. α B. α2 C. β1 D. β2 E. β3
B. α2
Catecholamine receptor in pancreatic α cells A. α B. α2 C. β1 D. β2 E. β3
D. β2
The primary mechanism of action of catecholamines with α1-adregrenergic receptors A. Increased IP3 and Ca++ B. Increased DAG C. Increased cAMP D. Decreased cAMP E. Both A and B
E. Both A and B
The primary mechanism of action of catecholamines with α2-adrenergic receptors: A. Increased IP3 and Ca++ B. Increased DAG C. Increased cAMP D. Decreased cAMP E. Both A and B
D. Dec cAMP
The primary mechanism of action of catecholamines with β-adrenergic receptors: A. Increased IP3 and Ca++ B. Increased DAG C. Increased cAMP D. Decreased cAMP E. Both A and B
C. Increased cAMP
Catecholamines that promote lipolysis in adipose
Both Epi and NE
Epinephrine increases blood glucose by:
glycogenolysis
gluconeogenesis
Common recursor of corticosteroids A. C22H40OH2 B. C27H45OH C. C25H40OH D. C22H45OH2
B. C27H45OH = cholesterol
cyclopentanoperhydrophenanthrene
Rate-limiting step in cholesterol synthesis
Conversion of cholesterol to pregnenolone via CYP11A1 or CytP450 after activation of protein kinase A
True or False:
Deoxycortisone mainly functions as glucocorticoid
False:
Deoxycortisone has little glucocorticoid activity but mainly
functions as mineralocorticoid.
True or False:
9a-fluorocortisol is mainly mineralocorticoid
True
Gene that allows production of the enzyme for the primary human mineralocorticoid
CYP11B2 for aldosterone synthase
True or False:
Majority of cortisol is secreted in the early morning
True
Which of the following exhibit circadian patterns? A. ACTH B. Androgens C. Cortisol D. AOTA
D. AOTA
PRENENOLONE → PROGESTERONE → 11-Deoxycorticosterone (DOC) → _______→ 18(OH) ________→ Aldosterone
Corticosterone
Enzymes necessary for the production of DHEA from pregnenolone
17α-hydroxylase
17, 20-lyase
The major conjugates of steroid hormones
Glucoronides
Cortisol is converted to cortisone as a reserve supply and can be converted back to cortisol when needed by the enzyme:
Cortisone to Cortisol: 11-β-hydroxysteroid dehydrogenase 1 (liver) & 11-β-hydroxysteroid dehydrogenase 2 (kidney)
Cortisol to Cortisone: 11-β-hydroxysteroid dehydrogenase 2
Protein that binds about 90% cortisol for transport in blood
Corticosteroid binding globulin (CGB) or transcortin
The key hepatic gluconeogenic enzyme stimulated by cortisol
Phosphoenolpyruvate carboxykinase (PEPCK)
Cortisol is a naturally occurring glucocorticoid released by the adrenal gland in response to a wide variety of stressful events, including fear and the other forms of psychological stress, vigorous exercise, acute trauma, surgery, or severe infection. The responses produced by cortisol can be divided into metabolic effects and anti-inflammatory effects that are mediated primarily by changes in gene expression. Which of the following is a metabolic effect produced by elevated levels of this hormone? A. Reduced muscle catabolism B. Reduced lipolysis C. Increased insulin sensitivity D. Hyperglycemia
D. Hyperglycemia
These hormones bind with protein receptors inside the cell rather than in the cell membrane, are lipid soluble, readily cross the cell membrane and interact with receptors in the cytoplasm or nucleus, EXCEPT: A. Steroid hormones B. Gonadal hormones C. Catecholamines D. Thyroid hormones
C. Catecholamines
In catecholamine biosynthesis, in adrenal medulla, cortisol stimulates conversion of which of the ff? A. Norepinephrine to epinephrine B. Dopamine to DOPA C. Epinephrine to norepinephrine D. Tyrosine to dopamine
A. Norepinephrine to epinephrine
Psychosis occurring with either excessive or deficient cortisol
Frank psychosis
True or False:
Polycythemia occurs when cortisol levels are deficient
False:
Polycythemia occurs when cortisol levels are excessive
Anemia occurs when cortisol is deficient
→ Cortisol stimulates erythropoietin synthesis and increases red blood cell production
True or False:
Cortisol increases the glomerular filtration rate
by both increasing cardiac output and acting DIRECTLY on the kidney
True
True or False:
High cortisol can lead to Hyperkalemia
False:
High cortisol can lead to Hypokalemia
→ Muscle weakness is caused by the hyperpolarization of the plasma membrane making it more difficult to stimulate
Receptors utilized by ACTH to stimulate cortisol synthesis
Melanocortin 2 Receptor (MC2R)
True or False:
The whole adrenal cortex participates in the negative
feedback loop
False
Zona reticularis does NOT participate in the negative
feedback loop.
Aldosterone regulates electrolyte metabolism by stimulating epithelial cells of distal nephron to SECRETE:
H+ and K+
REABSORBE: Na+ and Cl-
True or False:
Too little Aldosterone causes hyperkalemia and cardiac toxicity
True
True or False:
Cortisol also has mineralocorticoid activity
True:
Cortisol also has mineralocorticoid activity, but only 1/400th that of aldosterone
Expression of procollagen genes and MR-induced fibroblast-dependent interstitial and perivascular collagen deposition is an effect of which hormone?
Aldosterone = Cardiac and Vascular Fibrosis
The only region of the adrenal cortex that does not atrophy upon pituitary failure
Zona glomerulosa
Since aldosterone is primarily regulated by Angiotensin II through renin-angiotensin aldosterone system (RAAS).
Rise in ACTH can also increase aldosterone but it’s much less potent stimulus
True or False:
Increased extracellular K+ greatly increases aldosterone secretion by direct stimulation
True
True or False:
ACTH is necessary for aldosterone secretion but has little effect in controlling the rate of secretion in most physiologic conditions
TRUE
Enzymes necessary for cortisol metabolism that are diminished in prolonged phase of illness
5α reductase
11β hydroxysteroid dehydrogenase
