neuroendocrinology Flashcards
What is AP and PP surrounded by
- bone: sphenoid
- fluid called diaphragm sella
names for posterior pituitary
pars nervosa, neural lobe, neurohypophysis
names for anterior pituitary
adenohypohysis, pars distalis
paraventricular nucleus and supraoptic nucleus
nuclei in the hypothalamus that synthesize peptide hormones; axonal projections extend to pituitary stalk
hormones synthesized in the SON and PVN released in the PP–> hormones flow to the general circulation and blood flow
neurotransmitter release and exocytosis
action potential–> depolarization of axon terminal–> opening of calcium channels and a calcium–> trigger exocytosis of synaptic vesicle contents–> neurotransmitters diffuse across synaptic cleft and bind with receptors on post-synaptic cell–> response in the post-synaptic cell
neurophysin
a carrier protein that increases the half life of oxytocin and vasopressin by 10x by protecting them from being broken down by peptidases
oxytocin functions
- milk ejection reflex
- uterine contractions
- maternal behaviors
- sex behaviors in female rats
- orgasm
- males: sperm transport
- female PV pair bonding
milk ejection reflex
- stimulation of nipple–> brain activity in the mom
- hypothalamic cells receive info from periphery
- cells in the hypothalamus (SON and PVN) produce oxytocin and release it from the PP
- oxytocin causes cells of mammary gland (myoepithelial cells surrounding lumen) to contract–> release milk
Vasopressin functions
- water retention in the kidneys (anti-diuretic hormone)
- increase in blood pressure
- male PV: pair bonding
solute
particles in liquid, part that is NOT water
solvent
liquid in which solute dissolves
solution
solute+solvent
isotonic
same amount of solute on either side
hypotonic
more salt inside the cell than water–> water flows INSIDE–> swelling of the cell
hypertonic
more water inside the cell than salt–> water flows OUT–> shrinking of cell
glomerulus
a capillary bundle that forms the first step in filtering blood from the urine
nephron
a filtering unit–each continues a glomerulus and tubule
tubule
returns substances to blood and pulls out wastes
-blood vessels run alongside tubules–> reabsorb water, minerals, and nutrients
aquaporins
proteins embedded in the loop of Henle that allow water to be reabsorbed
-structured in a 6-alpha helices bundled together
mechanism of vasopressin action
- vasopressin binds to vasopressin receptors on the membrane of renal tubule cells
- G-protein activation–> activation of adenylate cyclase–> formation of cAMP–> activation of protein kinase
- aquaporins phosphorylated by PK
- self-assembly of aquaporin tetramers
- insertion into cell membrane to increase the absorption of water by blood
pituitary portal system
system of blood vessels (capillary bed of the superior hypophyseal artery) that connect the hypothalamus to the anterior pituitary
-releasing/inhibiting hormones synthesized in the hypothalamus project to portal system–> released to anterior pituitary–> synthesis of trophic hormones
acidophil
take up acid stains
-GH, prolactin
basophil
take up basic stain
-TSH, gonadotropins
chromatophobes
take up either stain
-ACTH
thyroid hormones
RH: TRH
trophic hormone: TSH
act on thyroid gland: T3 or T4 (differ in number of iodine)
function: metabolism, body temperature
Prolactin
RH: TRH IH: dopamine trophic hormone: prolactin acts on mammary cells, ovary, brain function: milk production, lactose maintenance of corpus leutum, induction of maternal behavior
GH
RH: GHRH IH: GHIH, GHRIH, somatostatin trophic hormone: growth hormone target: liver, bone, muscle function: body growth, carbohydrate, protein, and lipid metabolism
GH increases cell permeability–> increased uptake of amino acids–> increased protein synthesis
ACTH
RH: CRH
trophic hormone: ACTH
target: adrenal cortex: cortisol, corticosterone
function: increased glucose availability and other effects
gonadotropins
RH: GnRH trophic hormones: FSH, LH target: ovary, testis function (FSH) a. follicle development b. spermatogenesis function (LH) a. ovulation, formation of corpus leutum, stimulation of leading cells b. testosterone release--> spermatogenesis, male secondary sex characteristics
ultrashort feedback loop
hypothalamic releasing/inhibiting hormones limit their OWN release by an autocrine effect on targets in hypothalamus
short loop
inhibition of releasing hormones by pituitary hormones
direct long feedback loop
hormone produced by gland inhibits pituitary (trophic) hormones
indirect long loop feedback
hormone produced by gland inhibits hypothalamic hormones (releasing hormones)
