adrenal glands Flashcards
generally describe the adrenal cortex
- outer portion of the adrenal gland
- made of 3 layers
- secrete steroid hormones
generally describe the adrenal medulla
- inner portion of adrenal gland
- produces amine hormones
where are mineralocorticoids secreted from
zona glomerulosa, outermost cortex layer (G)- 10% of volume
where are glucocorticoids secreted from
zona fasciculata, middle cortex layer (F) - 75% of volume
where are sex hormones secreted from
zona reticularis, inner layer of cortex (R) - 15% of volume
list the function of steroid hormones
- mineralocorticoids: regulate salt balance
- glucocorticoids: assist with carbohydrate metabolism
- androgens: required for sexual function but less so than gonads
describe aldosterone
- produced in G zone (outer layer)
- controls salt and water retention
- controlled by RAAS of kidney
describe the overall effect of aldosterone
- vasoconstriction to increase BP
- increased sodium retention and potassium excretion, increasing water retention
- overall increases BP and BV
describe primary adrenal disease
- aldosterone secreting adrenal adenoma = Conn syndrome
desrive secondary hyperaldosteronism
- RAAS disorder produces excess renin
describe hypoaldosteronism
- primary = Addison’s disease, atrophy o fadrenal glands w/ depressed production of aldosterone and glucocorticoids
- congenital deficiency of 21-hydroxylase
- decreased secretion of aldosterone and cortisol
describe variation of cortisol levels in the body
diurnal variation (ACTH same)
list the steps of cortisol regulation
1) hypothalamus (CRH)
2) anterior pituitary gland (ACTH)
3) adrenal glands (cortisol)
- negative feedback loop
describe primary hyperadrenalism
adrenal gland misfunction causing increased cortisol release with low ACTH and CRH
describe secondary hyperadrenalism
pituitary gland misfunction causing excess ACTH release and subsequent cortisol release
- also referred to as Cushings disease
what test can be run to differentiate eptopic tumor vs secondary hypoadrenalism
dexamethasone suppression
- inhibits production of ACTH from pituitary gland
what is the difference between cushing’s syndrome and cushings disease
- disease is secondary hyperadrenalism
- syndrome is a general term for cortisol excess
describe tertiary hyperadrenalism
hypothalamus misfunction causing excess release of CRH which leads to excess cortisol and ACTH
what are catecholamines synthesized from and where
made in adrenal medulla from tyrosine
- include epinephrine, norepinephrine and dopamine
describe the function of epinephrine
converts glycogen to glycose for greater work output
describe function of norepinephrine
neurotransmitter affecting vascular smooth muscle and heart
describe function of dopamine
neurotransmitter in the brain affecting vascular system
what is the metabolite of dopamine
homovanillic acid
what is the metabolite and final product of norepinephrine metabolism
- normetanephrine metabolite
- vanillylmandelic acid
what is the metabolite and final product of epinephrine metabolism
- metanephrine metabolite
- vanillylmandelic acid
describe pheochromocytoma
a tumor of the adrenal medulla causing increased epinephrine and norepinephrine
describe neuroblastoma
tumor of the adrenal medulla (in kids) causing epinephrine, norepinephrine and dopamine excess
- increased HVA and VMA urinary excretion (metabolism end products)
define adrenal incidentaloma
an adrenal mass > 1 cm discovered via imaging for nonadrenal pathology
true or false
the testes are a part of the hypothalamic-pituitary-gonadal axis
true
how is testosterone related to LH and FSH
LH and FSH are released by anterior pituitary gland and inhibited by increased levels of testosterone
describe congenital adrenal hyperplasia (CAH)
caused by 21-hydroxylase deficiency that prevents cortisol production
describe hyperandrogenemia
can cause precocious puberty in males and development of male secondary sex characteristic in female children
describe primary hypoandrogenemia
called klinefelter syndrome (XXY), decreased amounts of testosterone produced
describe secondary hypoandrogenemia
pituitary or hypothalamus disorder causing decreased synthesis of LH and FSH
describe estrogen and progesterone impact on LH and FSH formation
estrogen and progesterone have a negetive feeback control on LH and FSH
describe estrogen
- secretion
- differeing forms
- principle form
- secreted by ovarian follicles and placenta
- estradiol-17beta, esterone and estradiol
- estradiol is primary estrogen made by ovaries
describe function of progesterone
secreted by corpus luteum after ovulation
- increased in luteal phase
- decreased in follicular phase
what is the role of FSH in the first half of the menstrual cycle
promotes growth of ovarian follicles and increases estrogen
how does an increase of estrogen impact LH midcyle
decreases LH and FSH levels (negative feedback)
what hormone triggers ovulation
LH
what does the follicle become during menstrual cycle
following ovulation the follicle becomes the corpus luteum which produces estrogen and progesterone
if there is no fertilization during the menstral cycle what occurs
- lack of hCG (fertilization) causes corpus luteum to degenerate
- decreases in estrogen and progesterone
what characterizes the follicular phase of menstration
estrogen stimulates growth of uterine lining
low levels of progesterone
what characterises the luteal phase of the menstrual cycle
progesterone promotes endometrium tissue to accept fertilized egg
progesterone measurements are used to confirm ovulation period
describe hyperestrinism
causes precocious puberty in females and testicular atrophy in males
how can progesterone impact menstrual cycle in increased and decreased levels
- malignant increase prevents menstrual cycle from occurring
- malignant decrease causes infertility and abortion of fetus
