Adrenal Physiology Flashcards
T/F adrenal cortex and medulla have separate embryological orgins
True, they just fuse during development
What does the adrenal medulla secrete?
catecholamines and neurohormones
T/F adrenal medulla is a true endocrine gland
False, it is a modified SNS ganglion
What are the three zones of cortex?
zona reticularis
zona fasciculata
zona glomerulosa
T/F Reticularis is the outer most layer of the adrenal gland
false, it’s the innermost layer of the cortex
What the the zona reticularis secrete?
androgens, estrogens, DHEA
Where are glucocorticoids secreted?
mostly in the fasciculata, but also in the reticularis
What does the glomerulosa secrete?
mineralocorticoids, mostly aldosterone
What is the function of aromatase?
make DHEA or estradoil from androgen or testosterone
Which enzyme converts progesterone to cortisol and aldosterone
21-hydroxylase
T/F Stress can increase cortisol secretion
true
T/F We keep up a constant cortisol level at all time
False, the secretion follows circadian rhythm
What are the functions of CRH?
signal ACTH release effects on immune response inhibition of appetite signal onset of labor linked to mood disorders
What is POMC?
the precursor protein of ACTH
T/F Rise in ACTH gives rise to more a-MSH
True, ACTH undergoes proteolysis to make a-MSH
What are the functions of cortisol?
stimulate energy catabolism
permissive for glucagon and catecholamine actions
suppress immune system
negative Ca balance
Why do we need to taper the doses of cortisol when we want to get off the drug?
with long term use, adrenal gland will be desensitised, so we need to gradually build up the tolerance for atrophic cells
What are the signs of excess cortisol
Cushing’s - weight gain, increased catabolism, weakness of muscle, immune suppression, effects on HPO and HPT axis
Which cell in the adrenal medulla secrete neurohormones
chromaffin cells
