Endocrine- pituitary Flashcards
Endocrine System Consists of tissues that orchestrate ______ (homeostasis)
metabolic equilibrium
Means of communication mediated by secreted molecules (______) released by endocrine tissue (gland) and carried through the blood to a distant tissue (target cell/tissue)
hormones
Target tissue often secretes factors that down-regulate the activity of the gland (______)
feedback inhibition
Pathology occurs when there is:
Underproduction or overproduction of hormones
Mass lesions of hyperplastic glandular tissue
Lesions may be _____ (don’t produce hormones)
nonfunctional
Lesions may be _____ (produce hormones)
functional
Mass lesions of hyperplastic glandular tissue
may be __________ and can ________.
Benign or malignant
compress other tissues (e.g., vasculature, nerves)
Anterior lobe (adenohypophysis) is what percent of pituitary gland
80%
Hypothalamus releasing factors (positive) are carried to the anterior pituitary by the______.
portal vascular system
Hypothalamus releasing factors (positive) are carried to the anterior pituitary by the portal vascular system, Except for _____.
Prolactin secretion inhibited by hypothalamic dopamine (not stimulated)
Growth hormone secretion stimulated by GHRH and inhibited by somatostatin (both from the hypothalamus)
Prolactin secretion inhibited by hypothalamic ______(not stimulated)
dopamine
Growth hormone secretion stimulated by ___ and inhibited by somatostatin (both from the hypothalamus)
GHRH
Growth hormone secretion stimulated by GHRH and inhibited by______ (both from the hypothalamus)
somatostatin
in posterior pituitary, Modified glial cells and axonal processes from the hypothalamus, pass through the _____ to the posterior lobe (axon terminals)
pituitary stalk
Pre-formed hormones produced in the _____, stored in the axon terminals in the posterior pituitary, released directly into the systemic circulation
hypothalamus
Posterior pituitary hormones
Oxytocin Antidiuretic hormone (ADH or vasopressin)
what causes release of oxytocin or ADH
Direct CNS stimulation causes release
Dilatation of the cervix (pregnancy) and nipple stimulation (suckling) results in ____ release (also “happy” times!)
oxytocin
Decreased blood pressure (cardiac atria and carotid baroreceptors), increase in plasma osmotic pressure detected by CNS osmoreceptors stimulates ____ release (opposite effects inhibit)
ADH
Diseases of the posterior pituitary often noticed quickly because of increased or decreased secretion of ___
ADH
what is Hyperpituitarism
Excess secretion of pituitary hormones
causes of hyperpituitarism
Functional pituitary adenoma
Hyperplasia or carcinoma of the anterior pituitary
Ectopic secretion of hormones by non-pituitary tumors
Over-secretion of hypothalamic releasing factors
causes of Hypopituitarism
Pituitary or hypothalamic injury
- Ischemic injury (including compression injury, thrombolic / embolic injury)
- Surgery or radiation
- Inflammatory reactions
Nonfunctional pituitary adenomas (replaces functional tissue)
what is Hypopituitarism
Under-secretion of pituitary hormones
examples of Pituitary or hypothalamic injury
- Ischemic injury (including compression injury, thrombolic / embolic injury)
- Surgery or radiation
- Inflammatory reactions
Sellar expansion, bony erosion, and
disruption of the diaphragma sella can cause pituitary _____.
Local mass effects
Expanding pituitary lesions often compress the _____(visual field abnormalities, classically bitemporal hemianopsia)
optic chiasm
pituitary mass effects May produce signs and symptoms of elevated ____(headache, nausea, and vomiting)
intracranial pressure
Acute hemorrhage into an adenoma causes rapid enlargement of the lesion, called pituitary ____ (i.e., pituitary stroke, a neurosurgical emergency)
apoplexy
Most common cause of hyperpituitarism is an ______.
anterior lobe adenoma
anterior lobe adenoma Can be _____(hormone excess and clinical manifestations) or _____(without clinical symptoms of hormone excess, present late)
functional
non functioning
Less common causes of _____include pituitary carcinomas and some hypothalamic disorders (unregulated secretion of releasing factors)
hyperpituitarism
anterior lobe adenomas are
Usually found in adults ___ years
35 to 60
Pituitary adenomas are well-circumscribed lesions usually confined to the _____(may extend superiorly through the diaphragm sella into the suprasellar region, where they may compress the optic chiasm and cranial nerves.
sella turcica
_______ tend to be more invasive and contain areas of hemorrhage and necrosis.
Macroadenomas
headaches occur when there is inflammation/irritation to the ____.
dura
if there is disruption of bony sella, CSF can be released and pt will have ___.
rhinorrea
most common pituitary adenoma
prolactinoma
associated symptoms with ACTH
Cushing syndrome (hypercortisolism) Nelson syndrome (reactive adenoma after adrenalectomy)
associated symptoms with GH (IGF-1)
Gigantism (children)
Acromegaly (adults)
associated symptoms with Prolactin
Galactorrhea and amenorrhea (in females)
Reduced libido, infertility
Most common manifestation
associated symptoms with Prolactin, GH
Combined features of GH and prolactin excess
associated symptoms with TSH
hyperthyroidism
______ refers to the loss of one or more pituitary hormones
Hypopituitarism
______ results from complete loss of all pituitary hormone secretion
Panhypopituitarism
Causes
of Panhypopituitarism
Ischemic necrosis (head injury, vascular, postpartum)
Sella turcica neoplasms (nonfunctioning adenoma)
Intrasellar cysts
Chronic inflammatory lesions (TB, syphillis, sarcoidosis)
Infiltrative disorders (amyloidosis, hemochromatosis)
Genetic mutations
A syndrome of polyuria resulting from the inability to concentrate urine and to conserve water due to inadequate ADH
Diabetes Insipidus
diabetes insipidus causes
Reduced pituitary production of ADH (central diabetes insipidus)
Reduced renal response to ADH (nephrogenic diabetes insipidus)
Pregnancy increases metabolic clearance of ADH (so it lasts longer), decrease water reabsorption
____ is Due to secretion of more ADH than is appropriate for the blood sodium concentration or volume
SIADH
Associated with dilutional hyponatremia without edema
SIADH
SIADH- About 30% cases are _________ (hyperpituitarism), remainder are other CNS disorders, neoplastic, pulmonary, drug effects
posterior pituitary oversecretion
Neurologic consequences of _____include confusion, lethargy and weakness, myoclonus, asterixis, generalized seizures, and coma
hyponatremia
