Hypothalamus Flashcards
adenohypohysis is another term for what?
anterior pituitary
neurohypophysis is another term for what?
posterior pituitary
the anterior pituitary is made up of what type of tissue and is derived from what
epithelial tissue
formed by an upgrowth of ectoderm cells from the roof of the embryonic pharynx
posterior pituitary is what type of tissue and formed from what
neural tissue
formed from downward evagination of the floor of the embryonic brain
magnocellular neurons originate from where?
supraoptic and paraventricular nuclei of hypothalamus
magnocellular neurons release what hormones
ADH
oxytocin
magnocellular neurons (path and termination)
from hypothalamus through infundibulum of pituitary and terminate in close proximity to capillaries of the posterior pituitary
what is part of the precursor for ADH but not oxytocin
glycopeptide domain
what occurs to ADH and oxytocin pre-prohomrone as it goes through ER and golgi
signal peptide removed (in ER) and prohormones packaged into secretory granules
what happens to ADH and oxytocin in the secretory granules
prohormone is cleaved to form mature hormone
neurophysin cleaved from prohormone
neurophysin cleaved from prohomone does what
form tetramers and bind the hormone
what happens when the membrane at the nerve terminal is depolarized
VG-Ca channels open and Ca2+ enters cells
leads to exocytosis of secretory product
neurophysins (what type of function do they have)
chaperone and folding function
how are ADH and oxytocin secretion regulated
direct neural control
neurons releasing ADH and oxytocin represent what part of what reflex
efferent limb of neuroendocrine reflex arc
hypophysiotropic hormones (what are they/what do they do)
neurosecretions
mediate direct hypothalamic control of anterior pituitary secretory function
hypophysiotropic hormones can also be called what
releasing homrones and inhibiting hormones
hypophysiotropic hormones are secreted where and by what
into primary capillary plexus of median eminence by parvicellular neurons of hypothalamus
how do hypophysiotropic hormones get to anterior pituitary
hypothalamohypophyseal portal vessels
what pituitary hormone’s release is normally under tonic inhibition and by what
prolactin is usually tonically inhibited by dopamine
what can stimulate prolactin release
TRH
what are the 5 main cell types of anterior pituitary
somatotrope thyrotrope lactotrope gonadotrope corticotrope
somatotrope (what stimulates them and what do they secrete
stimulated by growth hormone-releasing hormone (GHRH)
secrete growth hormone (GH)
somatotropes are inhibited by what
somatostatin (SS)
thyrotrope (what stimulates them and what do they secrete)
stimulated by thyrotropin-releasing hormone (TRH)
secrete thyroid stimulating hormone (thyrotropin or TSH)
lactotrope (what inhibits them and what do they secrete)
inhibited by dopamine (tonically) secrete prolactin (PRL)
gonadotrope (what stimulates them and what do they secrete)
stimulated by gonadotropin-releasing hormone (GnRH)
secrete luteinizing hormone (LH) and follicle stimulating hormone (FSH)
corticotrope (what stimulates them)
corticotropin-releasing hormone (CRH) arginine vasopressin (AVP aka ADH)
corticotrope (what do they secrete)
adrenocorticotropic hormone (corticotropin or ACTH) gamma-ipotropin (gamma-LPH) beta-endorphin
what releasing/inhibiting hormones work on target cell via cAMP (Gs) pathway
GHRH
CRH
what releasing/inhibiting hormones work on target cell via IP3 (Gq) pathway
GnRH
TRH
AVP
dopamine and somatostatin work on target cells how
Gi
inhibit cAMP formation and activation G-protien gated K+ cannels
tropic hormones (what are they)
hormones that regulate the activity of other endocrine glands
long feedback loops (what are they)
negative feedback of hormone released from target gland by tropic hormone on hypothalamus or pituitary
short feedback loops (what are they)
tropic hormones inhibit their own release by regulating the release of releasing/inhibiting hormones from hypothalamus
