Endocrine Flashcards
located near sella turcica of sphenoid bone
pituitary gland
inner layer of Rathke’s pouch, fenestrated capillaries, no BBB, located between anterior and neural lobes
pars intermedia
elongation of Rathke’s pouch, adenohypophysis, production of hormones, contains acidophils, basophils, and chromophobes
anterior lobe (pars distalis)
outgrowth of diencephalon, neuroectoderm, secrete melatonin, derived from glial like interstitial cells,
pineal gland
bright and pink chromophil, produces prolactin and GH
acidophil
gray and granular chromophil, produces ACTH, TSH, LH/FSH
basophils
dense core of granules in the neurohypophysis (posterior lobe), dilated axons contain oxytocin and vasopressin
Herring bodies
calcifications, “brain sand” in pineal gland
corpora arenacea
follicles contain follicular cells, precursors of T3/4
thyroid gland
in between follicles, contain clear cytoplasm, make calcitonin, derived from the neural crest
C cells
chief cells secrete PTH that stimulates osteoclasts to secrete calcium, oxyphil cells with mitochondria and pink cytoplasm
parathyroid gland
islets of Langerhans, beta cells secrete insulin, alpha cells secrete glucagon, delta cells secrete somatostatin, blood flow is paracrine secretion enters central and spreads to acini
endocrine pancreas
derived from intermediate mesoderm, produces steroid from cholesterol, contains reticularis and fasciculata (androgens, glucocorticoids), and glomerulosa (aldosteron)
adrenal cortex
derived from neural crest, produces catecholamines, supplied by medullary artery, modified postganglionic fiber
adrenal medulla
have fenestrated capillaires, release norepi and epi hormones
chromaffin cells
regulates blood Calcium by bone turnover or kidney reabsorption, increases calcitriol for GI calcium absorption, released when low calcium and high phosphate
parathyroid hormone action
produced in thyroid gland and C cells, lowers calcium by decreasing reabsorption in kidney and osteoclasts, used as a tumor marker
calcitonin
increased GI reabsorption of calcium
calcitriol
defective calcium sensing receptors, hypercalcemia not sensed until very high, on labs look for high calcium with high PTH
familial hypocalciuric hypercalcemia
elevated PTH –> hypercalcemia, kidney stones, low phosphate, high calcitriol, osteoporosis
primary hyperparathyroidism
low PTH, hypocalcemia, muscle twitching, tingling, Trosseau sign, long QT
hypoparathyroidism
increased calcitriol, more GI absorption, hypercalcemia, decreased PTH and more excretion, leads to kidney stones
sarcoidosis
candidiasis, hypoparathyroidism
polyglandular autoimmune syndrome type I
osteoitis fibrosa, high PTH and net calcium removed from bone
hungry bone syndrome
builds bone, secretes RANK-L
osteoblasts
resorption of bone, stimulated by RANK-L, inhibited by OPG
osteoclasts
neurons from hypothalamic nuclei, controlled by supraoptic and paraventricular nuclei, hormones ADH and oxytocin
posterior pituitary hypophysis
forms primary/secondary capillary plexus, controlled by hormones entering capillary in median eminence
anterior pituitary hypophysis
regulated by GHRH (growth hormone releasing hormone), inhibited by somatostatin, via calcium levels, produces GH
somatotroph
regulated by CRH(+) via cAMP, produce POMC –> ACTH, MSH
cortitroph
regulated by TRH(+) and somatostatin(-) via calcium, produces TSH
thyrotroph
regulated by GnRH (gonadotropin releasing hormone) via calcium levels, produces LH and FSH
gonadotroph
regulated by dopamine(inhibitory), and PRH (prolactin releasing hormone), produces prolactin
lactotroph
mistracking of neurons, anosmia (absence of olfactory bulbs and tracts), hypogonadism, X linked
Kallmann syndrome
target thyroid gland, stimulates synthesis and secretion of thyroid hormones
TSH
target ovary and testis, stimulates growth of follicles and estrogen secretion, acts on sertoli cells to promote maturation of sperm
FSH
on ovary: stimulates ovulation of ripe follicle and formation of corpus leuteum, stimulates estrogen and progesterone synthesis by corpus luteum
-on testis: stimulates Leydig cells to synthesize and secrete testosterone
LH
acts on most tissues, promotes growth in stature and mass, stimulates production of somatomedin, stimulates protein synthesis, usually inhibits glucose utilization and promotes fat utilization
Growth hormone (GH)
acts on mammary glands, promotes milk secretion
prolactin (Prl)
acts on adrenal cortex, prmotes synthesis and secretion of adrenal cortical hormones
adrenocrticotropic hormone (ACTH)
