Pituitary and Intro Endocrine Flashcards
What are the 3 broad classifications of endocrine disease?
- Impaired synthesis or release
- Abnormal Interaction (hormone & target)
- Abnormal response (by target)
OR
hyper / hypo / mass lesions
What’s the normal size and weight of pituitary gland?
1 cm and about 5 gm pumpkin shaped organ
What is this? And how is it sectioned?
normal pituitary
3 sections: adeno, neuro, intermediate
What makes up the adenohypophysis component of the pituitary gland? (the cell type and the hormone associated)
80% of gland, from Rathke’s pouch (oral ectoderm); five cell types
- Somatotrophs (GH),
- Lactotrophs (PRL) {both Acidophilic – red}
- Thyrotrophs (TSH),
- Corticotrophs (ACTH & MSH),
- Gondaotrophs (LH & FSH) {all Basophilic – blue}
What makes up the neurohypophysis component of the pituitary gland? (the cell type and the hormone associated)
An extension of CNS, contains Pituicytes (modified glia), secretion is from Herring Bodies (Oxytocin & ADH, which are made in Hypothalamus but released here)
Where are ADH and Oxytocin released?
at neurohypophysis from hypothalamus via hypothalamohypophyseal tract
Where does the superior hypophyseal artery brings blood?
to Primary Plexus, which connects to the Secondary Plexus via the Hypophyseal Portal Veins (this whole connection brings blood and releaseing hormones to the adenohypophysis)
Where does inferior hypophyseal a. provides blood?
to the neurohypohysis; from there, both sides flow to the systemic circuit
List and rank by frequency the 4 main causes of hyperpituitarism.
- adenoma in the anterior lobe
- hyperplasia and carcinoma of anterior lobe
- extra-pituitary tumor secretion (secretes trophic hormones)
- hypothalamic disorders (excess releasing hormones)
List and rank by frequency the 4 main causes of hypopituitarism
- ischemic injury
- surgery or radiation
- inflammatory reaction
- non-functional adenoma encroaching on normal tissue
How does pituatary adenoma lead to hypopituitarism?
the adenoma grows and compresses good tissue leading to reduced or loss of function
What’s the frequency of incidental pituitary adenomas at autopsy?
25% of routine autopsies
What’s the percentage of intracranial neoplasms that are pituitary adenomas?
10% of intracranial neoplasms
What’s the difference in size between microadenoma vs macroadenoma?
micro <1cm; macro > 1cm
Are pituitary adenomas normally monoclonal or polyclonal?
monoclonal
What are the different functions of pituitary adenomas?
non-functional; monohormonal; plurihormonal (esp. GH &PRL together)
List and rank by frequency the types of pituitary adenoma.
- prolactinoma (most common - 20-30%)
- GH cell (2nd most common)
- Null cell (20%; nonfunctional)
- ACTH cell (10-15%)
- Plurihormonals other than GH/PRL (10%)
- Gonadotroph cell (5%)
- GH/PRL cell (5%)
- TSH cell (1%)
What microscopically distinguishes a pituitary adenoma from non-neoplastic anterior pituitary parenchyma?
cellular monomorphism and lack of significant reticulin network
What’s the classic visual field defect associated with mass lesions in the sella turcica?
bitemporal hemionopsia (lose both temporal fields)
What’s clinically seen in patients with pituitary adenomas?
increased hormone secretion (type specific) or mass effect (includes: visual defects, increased ICP, hypopituitarism, hemorrhage associated with pituitary apoplexy, etc)
What are 4 consequences of hyper-prolactinemia?
amenorrhea, galactorrhea, loss of libido, infertility (~hypo LH & FSH)
What can potentially disrupt normal prolactin regulation?
- damage to dopaminergic neurons in hypothalamus
- damage to pituitary stalk
- DA inhibitory drugs that may lead to hyperprolactinemia
What is associated with aromegaly?
due to increased GH following closure of growth plates
have increased facial structures, hands, feet, viscera, and soft tissues
What is associated with gigantism?
due to increased GH before closure of growth plates
increased growth in long bones and overall body size, with disproportionately long arms and legs
