neuroendocrine control of internal milieu Flashcards
does the anterior pituitary or the posterior pituitary have cells that release hormones
anterior
does the anterior pituitary or the posterior pituitary have NO cells that release hormones
posterior
does the anterior pituitary or the posterior pituitary receive neuronal projections from the hypothalamus
posterior
does the anterior pituitary or the posterior pituitary receive NO neuronal projections from the hypothalamus
anterior
where do the cell body neuronal projections to the posterior pit come from
hypothalamus
which neurons stem from the hypothalamus
peptidergic and dopaminergic
which hormones are released from the posterior pituitary
oxytocin and vasopressin
what stimulates oxytocin release
- cervial dilation
- suckling at breast
what are the 3 main targets for oxytocin
uterus
mammary gland
brain
what does oxytocin do to the uterus
smooth muscle contraction
what does oxytocin do to the mammary gland
milk ejection
how does oxytocin cause milk ejection from the mammary gland
contraction of myoepithelial cells surrounding the mamary alveoli
what does oxytocin do to the brain
mating & parenting behavrious, love hormone
what does oxytocin do to vessels at high doses
vasodilation
does oxytocin cause vasodilation or constriction at high levels
vasodilation
what does oxytocin do to the fluid retention
weakly antidiuretic
besides the effects of oxytocin to the uterus, mammary gland and brain, what are 2 other things it does
vasodilation (high dose)
weak antidiuretic
what are 3 therapeutic uses for oxytocin
induce/augment labor
postpartum hemorrhage
induce postpartum lactation
what are 3 reasons that oxytocin would be used to induce are augment labor
early vaginal delivery
uterine inertia
incomplete abortion
what is intrauterine growth retardation
slow growth rate of unborn fetus due to inadequate placental functions
what is the oxytocin challenge test (like what does it examine)
examine how fetus responds to stress during delivery
what does uterine contraction do to blood flow to placenta
reduce
how do you test for intrauterine growth retardation
use oxytocin to contract uterus (slow blood flow to placenta) to test if there is a lowering in HR (if there is lowering, means there is poor placenta function)
what does a lowered HR mean with the oxytocin challenge test
that the placenta is poor functioning
what must happen if the oxytocin challenge test leads to a lowered HR
that they may require cesarean delivery
what causes the stimulation of vasopressin (3)
- increased plasma osmolarity
- decreased blood volume
- drop in BP
what is another names for vasopressin
ADH
what are 3 main targets/ effects of ADH
cardiovascular renal and pituitary
what are 3 different receptor targets of ADH
V1 V2 V3
what is the role of V1 receptor activation
smooth muscle contraction (cardio)
what is the role of V2 receptor activation + how
blood coagulation
stimulation of platelet aggregation & mobilization of coagulation factors
what is the role of V3 receptor activation
stimulates ACTH release
what are the 2 cardio effects of ADH
smooth muscle contraction (V1) and blood coagulation (V2)
what are the effects of ADH on pit gland
stimulates ACTH release
what does ACTH do
stimulates adrenal gland to release corticosteroids
what G protein is V1
Gq
what G protein is V3
Gq
what G protein is V2
Gs
what are the effects of vasopressin at the kidneys (3)
- increase water reabsorption (collecting ducts, insert channels)
- increase urea reabsorption (collecting ducts)
- increase Na+ reabsorption (distal tubules)
where does ADH increase water reabsorption
collecting ducts
how does ADH increase water reabsorption
inserting water channels
where does ADH increase urea reabsorption
collecting ducts
where does ADH increase Na+ reabsorption
distal tubules
what can ADH be used for therapeutically(2)
diabetes insipidus (characterized by large volume of dilute urine) and as a vasocontriction
why can ADH be used to treat diabetes insipidus
its characterized by large volume of dilute urine
what does ADH do to vessels
causes vasoconstriction
why can ADH be used therapeutically as a vasoconstriction
prophylaxis against bleeding in haemophilia (tooth extraction)
what stimulates melanotrophs
MSH releasing factor
where are melanotrophs
in the intermediate lobe
which hormone is released from the intermediate lobe
melanocyte-stimulating hormone
where is MSH releasing factor released from
hypothalamus
what inhibits melanotroph
DA
where does DA come from
hypothalamus
what are the 3 types of MSD
alpha
beta
gamma
what does alpha-MSH do
anti-inflammatory and anti-pyretic
how does alpha-MSH work
Gs coupled MC1 and MC3 receptors
what does gamma-MSH do
increase BP HR and cerebral blood flow
how does gamma-MSH work
Gs coupled MC4 receptors
what do melanocytes do
produce melanin (hair and skin colour, reacting to UV)
what do melanotrophs do
release MSH (alpha beta gamma)
what is melanoma and what causes it
abnormal proliferation of melanocytes due to excessive MSH
how are melanocytes activated
binding of alpha-MSH to MC1 receptors (Gs)
what are the 5 cell types in the anterior pituitary
corticotrophs thyrotrophs gonadotrophs lactotrophs somatotrophs
what do corticotrophs release
ACTH
what does ACTH stand for
adrenocorticotrophic hormone
what do thyrotrophs release
thyrotrophin (TSH)
where are corticotrophins
anterior pituitary
where are thyrotrophs
anterior pituitary
where are gonadotrophs
anterior pituitary
where are lactotrophs
anterior pituitary
where are somatotrophs
anterior pituitary
what do gonadotrophins release (what family of hormones)
gonadotrophins
what are 2 gonadotrophins
FSH and LH
what are 2 hormones that gonadotrophs release
FSH and LH
what does FSH stand for
follicle-stimulating hormone
what does LH stand for
luteinizing hormone
what do lactotrophs release
prolactin
what do somatotrophs release
growth hormone GH
whats another name for lactotrophs
mammotrophs
what causes lactotrophs to release prolactin
prolactin-releasing factors from the hypothalamus (thyrotrophin releasing hormone + oxytocin)
which 2 hormones cause lactotrophs to release prolactin
thyrotrophin releasing hormone + oxytocin
what are the 2 prolactin-releasing factors
thyrotrophin releasing hormone + oxytocin
where are thyrotrophin releasing hormone + oxytocin release ( prolactin-releasing factors)
hypothalamus
where does prolactin have its effect
mammary gland
what causes the hypothalamus to release prolactin-releasing factors
suckling reflex on berries
what is the prolactin-inhibitory facotir
dopamine
where does dopamine do its action in the prolactin pathway
inhibits lactotrophs
where does estrogen do its action in the prolactin pathway
onto lactotrophs and prolactin
what does estrogen do in the prolactin pathway
increase the proliferation of lactotrophs
what does DA do to prolactin secretion
reduce
what does estrogen do to prolactin secretion
increase
how does estrogen increase prolactin secretion
it increases the proliferation of lactorophs
what 2 things does prolactin do to the mammary gland
- stimulates milk production
- stimulates proliferation & differentiation of mammary gland tissue during pregnancy
what are 3 targets for prolactin
mammary gland
pituitary gland
ovary
what does prolactin do to the pituitary gland
inhibits gonadotrophin release
what does prolactin do to gonadotrophin release
inhibits
what does prolactin do to the ovaries
decreases the response to gonadotrophins
what is the result of prolactin decreasing the ovary’s response to gonadotrophins
inhibits ovulation during breast feeding
what happens to ovulation during breast feeding and why
prolactin decreases the responses to gonadotrophins in the ovary
what would be a class of drug that inhibits prolactin secretion
D2 receptor agonist
where are D2 receptors in the prolactin pathway
on lactotrophs
what happens when D2 agonists bind to the D2 receptor
there is a decrease in prolactin release
what are 2 therapeutic reasons to use a D2 receptor agonist
- hyperprolactinemia (infertility, hypogonadism, breast tenderness)
- prolactinomas (decrease tumor size and plasma prolactin levels)
what causes the hypothalamus to release GHRH and GHRP
stress
exercise
deep sleep
what does the hypothalamus release to start the growth hormone pathway
GHRH and GHRP
what does GHRH stand for
growth hormone releasing hormone
what does GHRP stand for
growth hormone releasing peptide
who releases GHRH and GHRP
hypothalamus
where does GHRH and GHRP act
on the somatotrophs
what activates the somatotrophs to release GH
GHRH and GHRP
what do the somatotrophs release
GH
where does GH act positively
on the liver
what happens when GH acts on the liver
it releases IGF-1
what acts as negative feedback on the hypothalamus in the GH pathway
GH
what acts as negative feedback on the somatotrophs in the GH pathway
IGF-1 and somatostatin
what does somatostatin do to the GH pathway
They act negatively on somatotrophs to reduce GH release
what does IGF-1 stand for
insulin-like growth factor
what are 2 things that IGF-1 do (2 places it acts)
inhibits somatotrophs (stop releasing GH) activates somatostatin (to inhibits somatotrphs)
what are 2 things that GH do (2 places it acts)
activates liver (to release IGF-1) inhibits hypothalamus (stop releasing GHRH and GHRH)
what are 3 things the hypothalamus releases in the GH pathway
GHRH
GHRP
somatostatin
which 2 things activate/ cause somatostain release
hypothalamus (it releases it)
IGF-1 (increases its release)
what is the source of growth hormone
recombinant human growth hormone
what does GH do to the liver
causes it to produces IGF-1
what does GH do to bones
causes longitudinal bone growth
what does GH do to muscle
amino acid uptake + protein synthesis (especially in skeletal muscle)
what are 2 things that can happen with too much GH
gigantism = in children acromegaly = in adults
what is the difference with gigantism and acromegaly
gigantism = in children acromegaly = in adults
what happens in acromegaly (Visual)
enlargement of facial structures, hands and feet
what can be 3 therapeutic uses of GH
- pituitary dwarfism
- short stature in Turner’s syndrome
- adult GH deficiency
what is pituitary dwarfism
GH deficiency in children
why can GH be used in turners syndrome
there is an associated short stature
what can cause adult GH deficiency
damage to hypothalamus or pituitary
what are 3 symptoms of adult GH deficency
obesity, reduced muscle mass, lack of energy