Lec 2 Hypopituitary Flashcards
Where are posterior pituitary hormones made?
made in hypothalamus; stored in pituitary
Is hypopituitarism vs end organ hormone deficiency more severe?
end organ deficiency is more severe –> in absence of pituitary trophic hormones end organs will still continue to secrete some hormone
What are 3 causes of hypopituitarism?
- primary pituitary disorder = loss of hormone secreting cells
- hypothalamic disorder = loss of releasing hormones
- extrinsic destruction of hypothalamus/stalk/pituitary gland
What is embryology of anterior pituitary?
derived from rathkes pouch = ectodermal pouch of primordial oral cavity
What is embryology of posterior pituitary?
direct extension of nervous system
What is a cranyopharyngioma?
tumor derived from remnants of rathkes pouch
What is the one exception to the rule that all of the hormones secreted from hypothalamus are peptides?
dopamine = modified tyrosine molec
Which part of pituitary connects to hypothalamus via capillary portal system?
anterior pituitary
What two hormones are secreted by posterior pituitary?
- ADH/vasopressin
- oxytocin
What are x etiologies of hypopituitarism?
- invasion [tumor/cystic lesion]
- iatrogenic [surgery/radiation]
- infiltration [sarcoid, hemochromatosis]
- infarction [postpartum sheehans]
- injury [head trauma]
- infection [TB, syphilis]
- immune [autoimmune
What type of cell secretes growth hormone?
somatotroph
What type of cell secretes TSH?
thyrotroph
What type of cell secretes LH/FSH?
gonadotroph
What type of cell secretes ACTH?
corticotroph
What type of cell secretes prolactin?
lactotroph
What is action/target organs of growth hormone?
stimulates linear growth and muscle mass by causing secretion of IGF1[somatomedin]
anti-insulin effects
What are 4 actions of T3/T4?
- thermogenesis = increase BMR via Na/K ATPase
- increase B1 receptors in heart –> increase CO/HR/SV
- bone growth
- CNS maturation
What is action of ADH?
regulates serum osmolarity and BP –> decreases serum osmolarity and increases urine osmolarity via aquaporins in kidney
What is action of prolactin?
stimulates milk production
inhibits ovulation and females and spermatogenesis in males by inhibiting GnRH synthesis and release
Where is anterior pituitary located?
sella turcica
What is action of LH?
stimulates sex steroid hormone synthesis in gonads