Endo USMLE Flashcards
woman presents with diffuse goiter and hyperthyroidism. What are the expected values of TSH and thyroid hormones?
low TSH & hight thyroid hormones
48y/o female presntes with progressive lethargy and extreme sensitivity to cold temperatures. What is the diagnosis
hypothyroidism
pt with elevated serum cortisol levels undergoes a dexamethasone does not decrease cortisol levels, but 8 mg does. What is the dz?
pituitary tumor
50y/o man complains of diarrhea. On physical exam his face is plethoric and a heart murmur is detected. What is the dx?
carcinoid syndrome
woman of short stature presents with shortened 4th and 5th metacarpals. What endocrine d/o comes to mind?
Albright hereditary osteodystrophy or pseudohypoparathyroidism
Nondiabetic pt presents with hypoglycemia but low levels of C pepetide. What is the dx?
Surreptitious insulin injection
cortex of the adrenal glands comes from what embryologic source?
mesoderm
medulla of the adrenal glands comes from what embryologic source?
neural crest
GFR corresponds to
Salt (Na+)
Sugar (glucocorticoids) and
Sex (androgens)
mneu: the deepr you go the sweeter it gets
What does GFR stand for?
zona glomerulosa
zona fasciculata
zona reticularis
what does the zona glomerulosa secrete
aldosterone
what is the primary regulatory control of the zona glomerulosa
renin-angiotensin
what does the zona fasciculata secrete
cortisol, sex hormone
what is the primary regulatory control of the zona fasciculata
ACTH, hypothalamic CRH
what does the zona reticularis secrete
sex hormones (e.g., androgens)
what is the primary regulatory control of the zona reticularis
ACTH, hypothalamic CRH
what do the chromaffin cells cells of the medulla secrete
catecholamines (epi, NE)
what is the primary regulatory control of the medulla
preganglionic sympathetic fibers
what is the most common tumor of the adrenal medulla in adults
pheochromocytoma
what is the most common tumor of the adrenal medulla in children
neuroblastoma
out of pheochromocytoma and neuroblastoma which one causes episodic hyperension
pheochromocytoma
how does the left adreanal gland drain blood
left adrenal ->left adrenal vein -> left renal vv -> IVC
how does the right adreanal gland drain blood
right adrenal ->right adrenal vein -> IVC
posterior pituitary is derived from what embryological origin
neuroectoderm
posterior pituitary secretes what
vasopressen and oxytoxin
where are vasopressen and oxytoxin made
hypothalamus
where are vasopressen and oxytoxin shipped
pituitary
where is the anterior pituatary derived from
oral ectoderm
what does the anterior pituitary secrete
FLAT Pig
FSH LSH ACTH, Melanotropin (MSH) TSH Prolactin GH
alpha subunit is a common subunit to
TSH, LH, FSH, & hCG
Beta subunit determines this
hormone specificity
islet of Langerhans are collections of these three types of cells.
alpha, beta, delta cells
what part of the pancreas are the alpha, beta, & delta cells most numerous
tail
from where do the islets of Langerhans arise
pancreatic buds
alpha cells secrete
glucagon
beta cells secrete
insulin
delta cells secrete
somatostatin
prolactin ____ dopamine synthesis and secretion from the hypothalamus.
increases
dopamine subsequently _______ prolactin secretion
decreases
dopamine agonists (e.g., bromocriptine) ______ prolactin secretion. Dopamine antagonist (e.g., most antipsychotics) __________prolactin secretions.
decreases
increases
in females prolactin inhibits_______ synthesis and release, which inhibits ovulation
GnRH
___________ this is commonly seen in prolactinomas
amenorrhea
what is the congenital adrenal hyperplasia: Female that is not maturing presents with HYPERTENSION, hypokalemia, she has decreased sex hormones, decrease cortisol, increased mineralocorticoids
17 alpha hydroxylase deficiency
this congenital adreanal hyperplasia is the most common form. It results in decreased cortisol (increased ACTH), decreased mineralocorticoids, increased sex hormones. Complications include masculinization, female psuedohermaphroditism, HYPOtension, hyponatremia, hyperkalemia, increased plasma renin activity, and volume depletion. Salt wasting can need to hypovolemic shock int he newborn
21 beta hydroxylase deficiency
this congenital adreanal hyperplasia results in low cortisol, low aldosterone and corticosterone and high sex horones. Complicatons include masculinization and (HYPERtension (11-deoxycorticosterone acts as a weak mineralocorticoid)
11 beta hydroxylase deficiency
where does PTH come from (cells and tissue)
chief cells of parathyroid
what are the 4 fxs of PTH
1) increased bone resorption of Ca++ & phosphate
2) increased kidney resorption of Ca++ in the distal convoluted tubule
3) decreased kidney resoption of phosphate
4) increased 1,25 (OH)2 vitamen D (cholecalciferol) production by stimulating kidney 1 alpha hydroxilase
mneu: PTH increases serum CA, decreases serum PO, increases urine PO4, and stimulates both osteoclasts and osteblasts
PTH: phosphate trashing hormone
what causes PTH secretion
decreased serum Ca++
image p. 250 actions of PTH and 1,25 OH D in maitenence of Ca++ & phosphate homeostasis
shown are the main actions of PTH & 1,25 (OH)2 D in the maintenance of Ca++ and phosphate homeostasis
source of vit D3
sun exposure in skin
source of D2
plants
where are D2 & D3 converted to 25 OH vit D
liver
where is 25 OH vit D converted to 1,25 (OH)2 vit D (active form)
kidney
what is the fx of vit D
1) increased absorption of dietary Ca++
2) increased absorption of dietary phosphate
3) increased bone resorption of Ca++ & (PO4)3-
what dz do you get if you don’t get enough vit D (kids and adults)
kids-rickets
adults-osteomalacia
what is 24,25-(OH)2 vit D
inactive form of vit D
in the regulation of vit D, what does increased PTH cause
increase 1,25-(OH)2 vit D formation
in the regulation of vit D, what does decreased [Ca++]cause
increase 1,25-(OH)2 vit D production
in the regulation of vit D, what does increased 1,25-(OH)2 vit D cause
increase 1,25-(OH)2 vit D inhibits its own production
What dz?
Ca++: ↑
Phosphate:↓
Alk Phos:↑
hyperparathyroidism
What dz?
Ca++: N/↑
Phosphate:N
Alk Phos:↑↑↑
paget’s dz of bone
What dz?
Ca++: ↑
Phosphate:↑
Alk Phos:N/↑
vit D intoxication
What dz?
Ca++: N
Phosphate:N
Alk Phos:N
osteoporosis
What dz?
Ca++: ↓
Phosphate:↑
Alk Phos:N
renal insufficiency
where does calcitonin come from
parafolicular cells (C cells) of thyroid
what is the fx of calcitonin
↓ bone resorption of calcium
calcitonin opposes the action of what hormone
PTH
what stimulates calcitonin secretion
increased serum Ca++
the need for gene transcription and protein synthesis delays the onset of action of these steroid/thyroid hormones
mneu: PET CAT
Progesterone Esterogen Testosternone Cortisol Aldosterone Thyroxine and T3
these hormones are lipophilic and insoluble in plasma; therfore, they must circulate bound to specific binding globulins, which increase solubility and allows for increased delivery of steroid to the target organ.
steroid
increased levels of sex hormone-binding globulin (SHBG) leads to lower levels of free testosterone and results in this physical exam finding
gynecomastia
decreased SHBG raises free testosterone leading to this finding
hirsutism
these are iodine containing hromones taht control the body’s metabolic rate
thyroid hormones (t3/t4)
source of thyroid hormones
follicles of thyroid. Most T3 formed in the blood
fx of thyroid hormones
1) bone growth (synergism w/ GH
2) CNS maturation
3) beta adrenergic effects (increased CO,HR,SV, contractility
4) increase BMR via increased Na+/K+ ATPase activity -> increased O2 consumption, RR, increased body temp
5) increased glycogenolysis, gluconeogesis, lipolysis
mneu: T3 fx--4Bs Brain maturation Bone growth Beta adrenergic effects BMR incrase
what globulin binds most T3/T4 in blood
Throxine-binding globulin (TBG)
is free or bound thyroid hromone active
free
in what dz would you see decreased TBG
hepatic failure
in what condition would you see increase TBG
pregnancy