Hypothalamus CIS Flashcards
Major blood supply to ant pituitary is what
long portal vessels
minor blood supply to ant pituitary is what
short portal vessels
What type of hormones act on post pituitary
neuroendocrine
What type of hormones act on the anterior pituitary
tropic hormones from hypothalamus
How do pituitary adenomas affect vision
can press on optic chiasm
What hormones come from poist pituitary
oxytocin and ADH
What hormones come from ant pituitary
GH, prolactin, LH/FSH, TSH, ACTH
What groups of classes can cause hypopituitarism
pituitary diseases, hypothalamic disease, traumatic brain injury, stroke
What could be signs of postinfarction to anterior pituitary
fatgiue, unable to lactate, amenorrhea,, weight retention, skin a voice changes
What hormones explain fatigue? unable to lactate, amenorrhea, wight retention, skin and voice changes, BP
ACTH releases cortisol which maintains BP(so lack of)
TSH (weight control)
amenorrhea(lack of FSH and LH)
unable to lactate(porlactin)
If potassium levels are normal what hormone from pituitary can you expect is ok
aldosterone
Why would infarction to ant pituitary cause low blood glucose
no ACTH, no cortisol(helps maintain blood glucose)
Why are pregnant women susceptible to pituitary infarction?
The lactotrophs are enlarged due to pregnancy.
Also pregnant women have and enlarged pituitary
How come in Sheehan syndrome is the post pituitary relatively unaffected
blood from a different source- inferior hypophyseal a
does not enlarge during pregnancy
How is aldosterone level normal when ant pituitary infarcted
renin-angiotensin system
What are the physiologic causes of hyperprolactinemia
pregnancy, nipple stimulation, stress
What are the pathologic causes of hyperprolactinemia
lactotroph adenomas
decreased dopaminergic inhibition
What can cause decreased dopaminergic inhibition
hypothalamic and pituitary disease
drug use
What are other causes of hyperprolactinemia
estrogen, hypothyroidism, chest wall injury, chronic renal failure, idiopathic hyperprolactinemia
macroprolactinmeia
genetic
prolactin is inhibited by what
dopamine
Increased prolactin levels affect what hormone
suppress GnRH
how does central diabetes inspidus affect ADH levels
decreased released because suppresses secretions from posterior pituitary
If every anterior pituitary hormone is low except high prolactin what could be the cause
decreased secretion of dopamine which usually inhibits prolactin
problem to hypothalamus
infundibulum could have been severed. hormones not transmitted from hypothalamus to anterior pituitary
what would hormone levels look like in a pituitary adenoma
LH/FSH levels might be low because of feedback
prolactin levels would be high( inhibit gonadotropins)
What is the most common cause of acromegaly
somatotroph adenoma of anterior pituitary
What are the other causes of acromegaly
GHRH secretion from hypothalamic tumors or neuroendocrine tumors or ectopic GH secretion by neuroendocrine tumors
What stimulates GH release
deep sleep, alpha adrenergic, fasten, Ach, sex steroids, stress, aa, hypoglycemia, ghrelin
What are the supressors of GH release
obesity
beta adrenergics
glucocorticoids, high FFA, hyperglycemia, hypothyroidism, IGF-1
What inhibits release of IGF, intrinsic growth factor
undernutrition, acute illness, chronic illness, GH receptor deficiency, GHR Ab, IGF-1 R deficiency
describe the effects of protein intake, carb intake, and fasting on GH
protein intake increases somatomedin which increases GH
Carb intake causes no big change in somatomedin which decreases GH
fasting decreases somatomedin so increase in GH
How come in fasting GH increases and growth decreases
because there is a decrease in growth from decreased insulin from decreased somatomedin
What are the progressive changes in acromegaly
deepened skin creases, thickened skin, bulbous nose and lips, jaw appeared more prominent, hands were bulky
Why are IGF levels more useful in diagnosing acromegaly
if GH elevated IGF elevated, IGF is more durable and easier to detect
GH is very pulsatile
If there is a deficiency in hormones, what is the way to Dx
test it, try to activate it
What is bitemporal hemianopsia
blindness in certain visual fields
When are suppression tests used for hormone regulation testing
when it is suspected that there is over secretion
looking for normal regulation
What metabolic disturbances result in physical changes seen in acromegaly
increased lipolysis
increased protein synthesis (lean body mass)
glucose- GH opposes insulin so can result in DM II
How does the body compensate to the increased insulin insensitivity
hyperplasia of Beta cells
What are Tx for acromegaly from GH secreting tumor on ant pituitary
surgical resection of neoplasm, stereotactic radiotherapy
lifelonge medicaly therapy with somatostatin analogue octeotide or GH R antagonist pegvisomant
what is the effect of somatostatin on GH
inhibits further release through neg feedback loop
How does GH lead to increased linear growth
actions of IGF-1
altered cartilage metabolism
What is the effect of TRH on prolactin
increase amount released
Why in hypothyroidism is TRH increased
not getting feedback since no TSH is actually being released
