Test 1 (Week 2&3) Flashcards
(123 cards)
What are some potential manifestations of a decrease in extracellular free calcium levels?
–Paresthesias (numbness with “pins” and needles” sensations) –Tetanic contractions of skeletal muscle (often in hands, feet, or larynx)
How does 21-hydroxylase deficiency present ?
presents in infancy as salt wasting or childhood as precocious puberty; girls can present with virilization
The primary stimulus for insulin release is ____.
glucose
What is Cinacalcet and what do you use it for?
it’s a calcium mimetic used to decrease PTH secretion in secondary hyperparathyroidism (the result of chronic renal failure)
defined as adrenal gland failure due to bleeding into the adrenal glands, commonly caused by severe bacterial infection: Typically the pathogen is the meningococcus Neisseria meningitides. Hypotension, then shock, then DIC
Waterhouse-Friderichsen syndrome
How does diazoxide, an antihypertensive, inhibit insulin secretion?
it increases the activity of the ATP sensitive K+ channel on the Beta cell
What are the 3 things to remember about MEN type 1?
-Parathyroid (Hyperplasia and adenomas) -Pancreas( Gastronoma or Insulinoma) -Pituitary (Prolactinoma)
In Pseudohypoparathyroidism, Serum Ca2+ is low, but the PTH concentration is normal or elevated. How is this happening?
In most patients with pseudohypoparathyroidism, there is a congenital reduction in the activity of Gs, and PTH fails to produce a normal increase in cyclic AMP.
What’s the criteria for the diagnosis of diabetes mellitus based on hemoglobin A1C?
>6.5%
Whats the rate limiting step in adrenal steroidal biosynthesis?
transport of cholesterol to mitochondria by StAR
What’s the mechanism of action of Spironolactone ?
–Competes with aldosterone for receptors —-Prevents action of aldosterone —-K sparing diuretic
What’s the name of the synthetic aldosterone?
Fludrocortisone
What’s the diagnostic test for adrenal insufficiency?
inject Cosyntropin (first 24 Amino acids of ACTH) and measure plasma cortisol response
How does Calcitonin decrease serum calcium?
1) inhibits mobilization of calcium from bone 2) increases renal excretion of calcium
Cortisol can bind to the same mineralocorticoid receptor as aldosterone. How do cells with these receptors ensure that only aldosterone binds?
these cells have 11 beta-hydroxysteroid dehydrogenase, type 2, which converts cortisol to the inactive derivative, cortisone
What’s the rate limiting step in catecholamine biosynthesis?
conversion of tyrosine to dihydroxyphenylalanine (DOPA) by tyrosine hydroxylase
What do you give to treat Addison’s? What if this fails to correct fluid and electrolyte imbalances?
hydrocortisone b/c it has both glucocorticoid and mineralocorticoid activity; if this fails to correct fluid and electrolyte disturbances, use fludrocortisone (primarily mineralcorticoid activity)
What are some risk factors of Type 1 diabetes mellitus ?
family history (genetics), geography, viral exposure (particularly coxsackievirus)
What causes hypercalcemia associated with malignancy?
tumors that hyper secrete parathyroid hormone related protein (PTHrP)
What’s the mechanism of action of sulfonylureas?
close potassium channel in beta cell membrane –> cell depolarizes–> insulin released via increased Ca++ influx
How do sulfonylureas work?
directly inhibit the ATP sensitive K+ channels which depolarizes the membrane and activates voltage sensitive Ca++ channels which will trigger the release of insulin from the Beta cells (simply put, they lower blood glucose by stimulating insulin secretion)
What is the major metabolic effect of glucocorticoids (cortisol)?
stimulation of liver gluconeogenesis
What are the only two adrenal hormones essential for human life?
cortisol and aldosterone
List the second generation sulfonylureas
glimepiride, glipizide, and glyburide