Flashcards in adrenal Deck (74):
what type of neurons innervate the adrenal glands?
sympathetic postganglionic neurons
will the adrenal medulla regenerate?
will the adrenal cortex regenerate?
where is the zona arcuata (aka glomerulosa) located?
superficial adrenal cortex
where is the zona fasciculata + reticularis located?
deep in the adrenal cortex
where is the site of mineralocorticoid synthesis?
where is the site of glucocorticoid and sex hormone synthesis?
zona fasciculata + reticularis
is the zona arcuata responsive to ACTH?
is the zona fasciculata + reticularis responsive to ACTH?
loss of ACTH does what to the adrenal cortex?
produces a thin adrenal cortex
T/F: the thickness of the zona glomerulosa is affected by loss of ACTH.
what is the non-specific response to injury or stress by the adrenal glad?
general adaption syndrome
adrenocortical hormones are derivatives of what?
what are the two sources of cholesterol?
-synthesis in the adrenal cortex
-plasma LDL cholesterol
in the steroid nucleus of adrenocortical hormones, how many carbons are there?
what enzyme does trilostane block?
the synthetic pathway of adrenocortical hormone involves what 2 organelles?
-smooth endoplasmic reticulum
do mineralocorticoids have a C17 hydroxyl group?
do glucocorticoids have a C17 hydroxyl group?
where are binding proteins synthesized
what does total glucocorticoid in blood depend on?
-amount of carrier protein
how do steroid travel in aqueous solution (blood)?
binding protein carry the steroid
what are steroid binding proteins?
-transcortin for cortisol
-free hormone (no protein)
what is the reltaionshipt of [cortisol] to [aldosterone]?
[cortisol] is more than 10 fold higher than [adosterone]
what is the clearance of cortisol?
60 min half life
what is the clearance of aldosterone
20 min half life
what causes the differences in the half lives of cortisol and aldosterone?
the carrier protein
how/where are steroid hormones metabolized?
-reduction in the liver
-hormones rendered water soluble
-excreted in urine
what is the importance of mineralcorticoids?
they are acutely critical for maintaining life
what is the most important mineralcorticoid?
what does aldosterone protect against?
to prevent overstimulation of aldosterone receptor by cortisol, ______ converts ______ to inactive _____.
-11-b hydroxysteroid dehydrogenase
can cortisone bind to the mineralcorticoid receptor?
licorice can inhibit what?
leading to what?
-11-b hydroxysteroid dehydrogenase
-mineralcorticoid excess syndrome
what are the physiological actions of aldosterone?
-increases na+ reabsorption from urine, saliva and gastric juices
-increases angiontensin II production
-decreases K+ by increasing renal excretion
-conservation of water follows the conservation of na+
what behavior does aldosterone cause together with angiontensin II?
drives salt seeking behavior
what regulates aldosterone?
-plasma K+ will stimulate aldosterone by a DIRECT EFFECT ON adrenal zona glomerulosa
-poorly regulated ACTH
suppressed by atrial natriuretic factor
-high plasma Na+ and K+ deficiency decrease aldosterone secretion
aldosterone and angiotensin II act upon what?
distal tubule and collecting duct
what happens when aldosterone and angiotensin II are acting on the kidney?
-resorption of renal sodium and water
-excretion of potassium
where is renal renin released?
from the juxtaglomerular apparatus (JG)
do aldosterone and angiotensin II synergize?
the JG complex acts as what?
what is the most important glucocorticoid in most species?
what is the most important glucocorticoid in rabbits, mice and rats?
what is the main physiological effect of cortisol?
to stimulate gluconeogenesis -> amino acids to glucose, glycogen to glucose
cortisol acts on ____ to release ____.
what are the 7 effects of cortisol?
1. stimulate gluconeogenesis
2. stimulate protein and fat catabolism
3. redistribution of body fat
4. water and electrolyte distribution
5. trace mineral distribution
6. blocks inflammatory responses
7. suppresses immune system
what is the most clinically important effect of cortisol?
that it blocks inflammatory responses
how is cortisol regulated?
by negative feedback
what is the most important hormone of the pars intermedia?
what is the most potent glucocorticoid?
what are three ways you can test adrenocortical function?
1. plasma [cortisol]
2. ACTH response test
3. dexamethasone suppression test
what are 4 clinical uses of glucocorticoid?
1. inhibition of inflammatory response
3. palliative therapy for arthritis, arthrosis
4. replacement therapy for hypoadrenocorticism
what animals are most prone to hypoadrenocorticism?
older, female, small breed dogs
what is the common term for hyperadrenocorticism?
what causes cushing's disease?
secondary to pituitary release of excess ACTH
what causes cushing's syndrome?
primary hyperadrenocorticism due to adrenal tumor
what is cushings sydrome?
-excessive glucocorticoid synthesis
-secondary to excessive ACTH
what is the common name for hyperaldosteronism?
primary conn's syndrome is caused by what?
secondary conn's syndrome is caused by what?
renovascular disease leading to ang II increase
what is PPID in horses?
- pituitary pars intermedia dysfunction
what is a key sign of hypoadrenocorticism?
- bradycardia/widened QRS complex
what causes hypoadrenocorticism?
deficiency of mineralocorticoids (aldosterone)
cells of the adrenal medulla are innervated by what type of nerve fibers?
pre-ganglionic sympathetic nerve fibers
cells of the adrenal medulla are modified by what type of nerve fibers?
post-ganglionic nerve fibers
what are the primary hormones synthesized by the adrenal medulla?
epinephrine and norepinephrine
what is the key precursor for catecholamine synthesis?
tyrosine is inhibited by what?
NE and EPI
the actions of catecholamines are mediated by?
alpha- and beta-adrenergic receptors
the actions of catecholamines by alpha-receptors are?
-vasoconstriction by NE
the actions of catecholamines by beta-receptors are?
-increased heart rate/contractility
-adipose tissue lipolysis
-vasodilation by epinephrine
sympathetic tone is regulated by what?