Pituitary Gland Flashcards
How must a chemical messenger act to be classified as a hormone?
Must bind to a receptor either on the surface of the cell or w/i it
What is another name for the pituitary gland?
The hypophysis
What are the divisions of the pituitary?
The adenohypophysis (anterior) and neurohypophysis (posterior)
From where do Vasopressin and Oxytocin originate?
Axons and unmyelinated nerve fibers from the Hypothalamus
What five general compounds are secreted from the anterior pituitary
Corticotrophs (Proopiomelanocortin, Adrenocorticotropic hormone, melanocyte stimulating hormone, lipotropic hormone, endorphins), Lactotrophs (prolactin), Somatotrophs (GH), Thyrotrophs (TSH), Gonadotrophs (FSH, LH)
What are the cells that the posterior pituitary is composed of?
Pituicytes
What is hypopituitarism?
Secretion of one or more pituitary hormones is lacking
What is Sheehan’s Syndrome?
Panhypopituitarism caused by ischemic necrosis of the gland that may occur postpartum.
What is isolated growth hormone deficiency?
Congenital growth hormone deficiency
What is Laron Syndrome? What is it characterized by?
Growth Hormone insensitivity characterized by high levels of GH and low concentrations of Insulin-like growth factor
What is Kallmann syndrome?
Hypogonadotropic hypogonadism due (due to gonadotropin-releasing hormone deficiency) and anosmia
What is Empty Sella Syndrome? Cause?
Enlarged sella containing a thin flattened pituitary caused by a defective/absent diaphragma sella, which permits transmission of cerebrospinal fluid pressure into the sella.
What type of tumor will cause acromegaly?
GH/prolactin-secreting pituitary adenomas
What is the most important oncogene involved in sporadic pituitary tumorigenesis?
gsp
What is a pituitary adenoma < 10 mm diameter? Large adenomas?
Microadenomas, macroadenomas
What is a classic Syx of pituitary adenoma?
Bitemporal hemianopsia
What is the most common endocrinopathy associated with pituitary adenomas?
Hyperprolactinemia
What uscopic findings are characteristic of a lactrotroph adenoma?
Deposition of endocrine amyloid and presence of psammoma bodies
What do somatotrope adenomas secrete?
Growth Hormone
What does excess GH cause before bone epiphyses fuse? After?
Gigantism; Acromegaly
What is the difference betwixt Mixed Somatotroph-Lactotroph adenomas and Mammosomatotroph adenomas?
MSLAs are tumors w/ two cells types that respectively secrete GH and PRL which MAs are tumors composed of a single cell type that secretes both GH and PRL
A pituitary adenoma shows giant mitochondria, keratin 8-positive fibrous bodies and misplaced exocytosis. Dx?
Acidophil stem cell adenoma
What do corticotrope tumors secrete?
ACTH
What condition does ACTH excess induce?
Cushing disease
What is Crooke Hyalinization?
Filaments observed w/i the pituitary indicating massive cell hyaline deposition related to suppression of ACTH secretion by high circulating levels of cortisol
What do Gonadotrope tumors secrete?
LH and FSH
What is the rarest of all pituitary tumors?
Thyrotrope adenomas
What is the only significant condition associated with disease of the posterior pituitary?
Central diabetes insipidus
What is the biological basis of central diabetes insipidus?
Deficiency of ADH
One fourth of central diabetes insipidus cases are associated with brain tumors, especially this one. Dx?
Craniopharyngioma
