adrenal glands Flashcards
what is the blood suupply of the adrenals ?
supra renal arteries
what is the venous drainage of the adrenals ?
left adrenal - renal vein - IVC
right adrenal - IVC
what are the hormones produced by the cortex ?
mineralocorticoids
glucocrticoids
androgens
what hormones are produced by the medulla ?
epinephrine and norepinephrine
what are the embryological origins of the medulla vs the cortex ?
cortex - mesoderm
medulla - derived from the neural crest
what is the main mineralocorticoid made?
aldosterone
what is the release of aldosterone controlled by and what is the effect it imposes ?
RAA
effect - increase sodium water resorption
promotes potassium/ hydrogen excretion
what are the androgens made by the adrenals ?
DHEA
testosterone
androstenedione
what is the production of androgens controlled by ?
stimulated by ACTH
what is the major glucocorticoid made and how does it exert its effect ?
cortisol
activates or suppresses gene transcription
what is the pituitary adrenal axis ?
the hypothalamus secretes CRH
CRH stimulated the pituitary to release ACTH
ACTH stimulates the adrenal to secrete cortisol
where is CRH released from ?
paraventricular nucleus
what system does ACTH work on ?
cAMP/PKA 2nd messenger
what are the cortisol levels through out the day ?
highest early in the morning
lowest one hour after sleep
what are the effects of cortisol ?
cortisol increases in stress situations
mantains blood pressure
1- effect on vascular smooth muscle
2- increase vascular sensitivity to norepi
decrease NO mediated vasodilatation
what does an increase vs a decrease in cortisol levels do ?
increase in cortisol - causes hypertension and may result in cushing
a decrease in cortisol causes hypotension and may lead to adrenal insufficiency
what effect does cortisol have on the immune system ?
suppresses immune system
sequester lymphocytes in spleen
blocks neutrophil migration
blocks histamine release
inactivates NF-KB
what are the lab findings associated with an increase in cortisol levels ?
reduced t and b cells
increase in peripheral neutrophil count
lowers eosinophil count
what inflammatory transcription factor is inactivated by cortisol ?
NF-KB
what are the effects of cortisol on glucose ?
increases the rate of glucogenesis
more glucose produced by liver
more glycogen storage
leads to insulin resistance
how does cortisol increase the glycogen storage in the liver ?
through an increase in glycogen synthase
what effect does cortisol have on fats ?
increase total cholesterol
key effect - fat depostion
what effect does cortisol have on bones ?
negative effect
inhibit osteoblasts
what are the zones of the adrenal glands ?
1- zona glomerulosa - aldosterone
2- zona fasiculata - cortisol
3- zona reticularis (innermost) - testosterone
what is the significance of ketoconazole in adrenals ?
inhibits 17,20 lyase
less production of androgens
how can ketoconazole decrease cortisol synthesis ?
inhibits 17 alpha hydroxylase
and desmolase
decreasing cortisol
what is the effect of aldosterone ?
kolo by3la except potassium
what is the difference in effect between aldosterone and ADH ?
ADH - retains water only through aquaporin channels
Aldosterone - retains both sodium and water through sodium reabsorption
urine has less sodium due to effect of aldosterone
urine has less water due to the effect f ADH
