Flashcards in Endocrine Path Quiz 3- part 3 Deck (16):
parathyroid glands is controlled by the level of
free (ionized) calcium in bloodstream
decreased serum levels of free calcium stimulate the synthesis and secretion of
function of PTH
PTH tells kidneys to absorb more calcium from diet, and body to elaborate more of active Vitamin D
PTH and calcitonin act inversely, how?
PTH act to increase conc. of calcium in bloodstream
Calcitonin acts to decrease conc. of calcium
where is PTH made?
chief cells of parathyroid glands
where is calcitonin made?
parafollicular cells C cells
Sometimes these cells have a clear appearance due to large amounts of glycogen stored within the cell
most common cause of primary hyperparathyroidism?
other causes of primary hyperparathyroid?
microscopic view of parathyroid adenoma
tendency towards follicular formation
microscopic view of normal parathyroid
prominent adipose tissue
most common cause of secondary hyperparathyroidism?
Less phosphate excreted in urine, resulting in hyperphosphatemia. The elevated serum phosphate levels directly depress serum calcium levels and thereby stimulate parathyroid gland activity.
microscopic changes seen in secondary hyperparathyroidism
same as adenoma (primary hyperparathyroidism)
loss of adipose
but NOT encapsulated
microscopic view of parathyroid carcinoma
bands of fibrous tissue between nests of neoplastic cells
malignancy related to hypercalcemia most commonly due to
stem cell capacity of some cancer to make ectopic hormone called PTHrP (Parathyroid hormone-related protein) (resembles PTH)