Adrenal - cortex stuff! Flashcards
What does corticotrophin releasing hormone (CRH) do?
stimulates corticotrophs to release ACTH
decrease in which hormone causes the symptoms of decreased pubic and axillary hair and decreased libido in females?
decreased androgens
When is the greatest secretory activity of cortisol?
MORNING
21 b-hydroxylase deficiency effect on ACTH?
ACTH levels are HIGH (due to no cortisol)
high ACTH = trophic effect on adrenal gland (GROWTH OF GLAND)
What is the only thing that inhibits corticotrophin releasing hormone (CRH)
cortisol
17a-hydroxylase deficiency
(hyper/hypo)tension
(hyper/hypo)kalemia
metabolic (alkalosis/acidosis)
hypertension
hypokalemia
metabolic alkalosis
(same as conn syndrome except there is LESS aldosterone… effects from increased 11-DOC and corticosterone)
Conn syndrome is caused by:
an aldosterone-secreting tumor
Why is skin pigmentation normal with secondary and tertiary adrenocortical insufficiency but hyperpigmented in primary adrenocortical insufficiency (Addisons)
2/3: normal because ACTH is not over secreted from pituitary (hypothalamus and pituitary are the problems)
primary: hyperpigment because ACTH is over secreted from pituitary due to low cortisol from the adrenal gland which is the problem
(a-MSH is the reason for pigmentation which is a derivative of ACTH)
Why are renin levels low in Conn syndrome?
Due to the hypertension caused by aldosterone.
Only aldosterone is increased due to the tumor
Why does the adrenal gland enlarge with 21 b-hydroxylase deficiency
trophic effect on adrenal gland from high levels of ACTH (due to lack of cortisol)
What layers of the cortex contain desmolase
all layers
zona glomerulosa
zona fasiculata
zona reticularis
decrease in which hormone causes the symptoms of hypoglycemia, weight loss, and muscle weakness in Addison’s disease?
decreased cortisol
What is the LEAST important secretagogue for aldosterone synthesis?
ACTH
21 b-hydroxylase deficiency leads to:
(hyper/hypo)natremia
(hyper/hypo)glycemia
hyponatremia (no aldosterone!)
hypoglycemia (no cortisol!)
What causes hyperpigmentation of skin on elbows, knees, nipples, and scars in Addison’s disease?
increased ACTH —> increased a-MSH fragment
increased ACTH caused by low cortisol because only cortisol is the inhibitor of CRH —> which keeps ACTH stimulated
cortisol (and androgens) levels in the blood reflect a ______ and _______ release of ACTH
circadian and pulsatile release of ACTH
What are androgens responsible for in women?
- axillary hair
- pubic hair
- libido
What are the results of a 21 b-hydroxylase deficiency in utero?
masculinization of female penis-like clitoris scrotum-like labia deep voice increased muscle mass amenorrhea hirsutism
cortisol effects on bone:
decrease calcium absorption —> decrease plasma calcium —> mobilizes calcium from bone —> inhibits bone formation —> bone loss
(no calcium taken up from GI or kidneys, so the bones release calcium to make up for the decrease in plasma calcium which causes the bones to be deficient and cannot form new bone cells)
decrease in which hormone causes the symptoms of hyperkalemia, hypotension, metabolic acidosis, and salt craving in Addison’s disease?
decreased aldosterone
Which part of the adrenal gland responds to SHORT term stress?
medulla
Why are adrenal androgens referred to as 17-ketosteroids?
because they have a ketone at C17
cortisol effect on:
protein:
lipids:
glucose uptake:
protein CATABOLISM (synthesis is decreased)
lipoLYSIS (provides glycerol)
decreased glucose uptake by tissue (more in blood)
What does aldosterone bind to to stimulate sodium and water reabsorption? and potassium and H+ secretion?
intracellular mineralcorticoid receptor (MR1)
which binds to a mineralcorticoid responsive element (MRE)