Pituitary Flashcards
Pituitary gland
Two lobes
Beneath the sella turcica
Dual blood supply
Anterior pituitary hormones
ACTH - Regulation of adrenal cortex TSH - Thyroid hormones regulation GH - growth (+) LH/FSH - reproductive control PRL - Breast milk production
Pituitary hormones
ADH - water regulation
Oxytocin - breast milk expression
Pituitary cell types
Originally classified by their staining characteristics with acidic (orange) and basic (aldehyde fuscin dyes)
Clinical presentation of pituitary tumors
Hormones hypersecretion Space occupying lesion - Headaches - Visual loss (field defect) - Cavernous sinus invasion Hormone deficiency state Interference with surrounding normal pituitary
Tumors of the anterior pituitary can cause syndromes of hormone excess
GH - Acromegaly ACTH - Cushing's disease TSH - Secondary thyrotoxicosis LH/FSH - (non-functioning pituitary tumor) PRL - Prolactinoma
Some effects of GH/IGF-1 excess
Metabolic changes Impaired fasting glucose Impaired glucose Diabetes mellitus Skin tags and acanthosis nigricans Increased TG
Actions of cortisol
Increase Plasma glucose Increase lipolysis Proteins are catabolized [Na+] and water retention Anti-inflammatory Increased gastric acid production
Cushing’s syndrome
Changes in protein and fat metabolism
Changes in sex hormones
Salt and water retention
Prolactinomas
Common
PRL different control to all other anterior pituitary hormones - the tonic release of DA inhibits PRL release
Positive feedback
Nonfunctioning Pituitary tumors
30% of all pituitary tumors No syndrome of hormones excess produced Headaches Visual field defects Nerve palsies Deficiency of hormones
Treatment of pituitary hormones
Surgery
Radiotherapy
Drugs
Cause of pituitary failure
Tumor - benign or malignant Trauma Infection Inflammation Latrogenic
