Neuroendocrine/Pituitary Lecture Flashcards
What is the hypothalamus’ role in the autonomic nervous system?
It’s huge!
It integrates informaiton for the control of the endocrine system and does so by controlling the pituitary gland
What are the two parts of the pituitary gland?
anterior part: adenohypophysis
posterior part: neurohypophysis
What connects the pituitary to the hypothalamus?
the median eminence
also called the infundibulum
What two hormeons are secreted by the posterior pituitary?
vasopressin
oxytocin
What neurons synthesize vasopressin and oxygotcin?
the magnocellular neurons of the supraotic and paraventricular nuclei
What is another name for vasopressin?
anti-diuretic hormone (ADH)
What 3 things triggers vasopressin secretion?
increased blood osmolarity (so increase in solute)
decreased blood volume (hypovolemia)
hypotension
What is the effect of increased vasopressin secretion?
- increased water resorption by the kidney (dilutes blood and increases blood volume)
- vasoconstriction (increases blood pressure)
What are the stimui for oxytocin secretion?
suckling (nursing)
uterine stimulation by a fetus
What are the effects of oxytocin?
- causes constriciotn of tubules in the breast, causing milk ejection reflex in response to suckling
- Uterine contration to aid in delivery
What hormones does the anterior pituitary secrete? THere’s7….
- growth hormone
- prolactine
- thyroid-stimulating hormone
- follicle stimulatin ghormone
- lutenizing hormone
- adrenocorticotropic hormone
- beta-endorphin
What are the two somatomammotropins secreted by the anterior pituitary?
growth hormonea nd prolactin
What is the stimulus for growth hormone release and what is it’s main effect?
exercise, stress and sleep (80% released in sleep!)
growth ot tissue and metabolism
What is the stimuli for prolactin release and what is its effect?
suckling and stress
development of mammary tissue and lactation (milk production)
What do TSH, FSH, and LH have in common?
they are all glycoproteins with carbohydrate moieties
What is the stimulus for thyroid-stimulating hormone secreiton and what is its effect?
exposure to cold temperature
causes increased thyroid hormone secretion, leading to increased cellular metabolism and heat production
What is the effect of FSH in men and women?
men - spermatogenesis
women - development of ovarian follicle
What are the affects of lutenizing hormone on men and women?
men - REQUIRED for spermatogenesis, stimulates testosterone
women - the trigger for ovulation, stimulates projecterone from the spent follicle
What are the three hormones generated from cleavage of pro-opiomelanocortin (POMC)?
adrenocorticotropic hormone
beta-endorphin
melanocortin
what is the stimuli for both adrenocorticotropic hormone and beta-endorphin release?
stress
What is the effect of adrenocorticotropic hormone (ACTH)?
stimulates the release of cortisol form the adrenal cortex
What is the effect of beta-endorphin?
is acts as an analgesic on the mu opioid receptor
What test can be used to clinically assess anteiro rpituitary function?
do an insulin stress test
inject insulin, which will cuase blood glucose to go down. This is a stressful thing for the body, so you should see increased secretion of ACTH, Beta-endorphin, prolacting, and growht hormone
What neuorns synthesize the hypothalamic releasing hormones?
the parvocellular neurons
Where do the parvocellular neurons secrete the hypothalamic releasing hormones?
into the primary capillary bed within the median eminence, such that the releasing hormones can flow down to the anterior lobe via the hypophyseal portal vein.
What are the 4 excitatory hypothalamic releasing hormones?
for TSH?
FSH and LH?
ACTH and beta-End?
GH?
TSH - thyrotropin releasing hormone
FSH/LH - gonadotropin releasing hormone
ACTH and beta-end - corticotropin releasing hormone
GH - growth hormone releasing hormone
What hypothalamic releasing hormone decreases GH secretion?
somatostatin
What hormone’s secretion is inhibited by dopamine from the hypothalamus?
prolactin
What hormonal changes would you expect to see after a pituitary stalk section?
increase in prolactin
decrease in everything else
What hormone is lost in diabetes insipidus? how?
vasopressin
you have either head trauma or autoimmune disorders that cause desctruction of the magnocellular neurons
What are the two main symptoms of diabetes insipidus and why?
ultimately, you dont have vasopressin, so you don’t respond to low blood pressure, hypovolemia or osmolarity in the same way
this means you have polyuria - because ou can’t retain water
polydipsia - because you have to make up for the volume loss somehow
How do you treat diabetes insipidus?
you have to have a way to replinish the vasopressin without causing severe vasoconstriciton - you want one that will just act on the kdiney
desamino vasopressin
An overabundance of what hormone will cause galactorrhea/amenorrhea?
prolactin
WHat is the pituitary of galactorrhea - amenorrhea?
a pituitary timor which produces prolactin (usually a microadenoma)
this decreases the release of FSH and LH from the anterior pituitary
What are the treatment options for galactorrhea-amenorrhea?
- surgery to remove the tumor and thus decrease prolactin
- give a dopamine receptor agonist like bromocryptine to decrease prolactin release
