Wk1 Adrenal Physiology Flashcards
Section of adrenal cortex that produces aldosterone:
zona glomerulosa
middle zone of the adrenal cortex:
zona fasciculata
inner zone of the adrenal cortex:
zona reticularis
Embryological origin of adrenal medula:
neural crest
**modified ganglion releases catacholamines
Four “big picture” functions of cortisol:
- suppresses immune function
- gluconeogenesis
- protein catabolism
- lipolysis
CRH receptor type in anterior pituitary:
Gs –> increases cAMP
Pituitary precursor to ACTH, MSH, and a-lipotropin:
pro-opiomelanocortin (POMC)
Adrenal cortex receptor type for ACTH:
melanocortin-2
G-alpha-s –> elevates cAMP –> PKA activation
Rate limiting step in adrenal steroid synthesis:
CYP11A – cholesterol –> pregnenolone
Location of glucocorticoid receptors in target cells:
cytosol
Inactive form of cortisol:
Where is it found and why?
Cortisone
mineralcorticoid responsive tissue so aldosterone can bind and cortisone is inactive
Main function of mineralcorticoids:
Aldosterone –> salt and water retention
11BHSD2 ?
inactivates cortisol
11BHSD1 ?
activates cortisone to cortisol
Look at slide ….
17
Aldosterone effect on K+?
enhances secretion
Make sure you understand slide
20-30
What stimulates aldosterone?
high K+
AT II
ACTH – secondarily – no feedback inhibition
Immune mediated destruction of adrenal cortex:
Addison’s disease
What do cortisol, aldosterone, POMC, ACTH, and MSH look like in Addison’s?
cortisol – low
aldo – low
POMC – high (no feedback inhibitio)
ACTH – high “
MSH – high “ (pigmented skin)
Secondary adrenal insufficiency usually caused by:
withdrawl of exogenous glucocorticoids
