Hypopituitary Flashcards
What controls secretion by the anterior pituitary
Hypothalamic releasing and hypothalamic inhibitory hormones
Describe the origination and route of the hypothalamic releasing/inhibitory hormones
secreted in hypothalamus
and conducted to the anterior pituitary through minute blood vessels called hypothalamic-hypophysial portal vessels
What are the anterior and posterior pituitaries known as
Anterior - Adenohypophysis
Posterior - Neurohypophysis
What is TRH and what is its primary action on the anterior pituitary
Thyrotropin releasing hormone
Stimulates secretion of TSH by thyrotropes
What is GnRH and what is its primary action on the anterior pituitary
Gonadotropin-releasing hormone
Stimulates secretion of FSH and LH by gonadotropes
What is CRH and what is its primary action on the anterior pituitary
Corticotropin-releasing hormone
Stimulates secretion of ACTH by corticotropes
(adrenocorticotropic hormone controls cortisol production)
What is GHRH and what is its primary action on the anterior pituitary
Growth hormone releasing hormone
Stimulates secretion of growth hormone by somatotropes
What is another name for growth hormone inhibitory hormone and what is its primary action on the anterior pituitary
Somatostatin
Inhibits secretion of growth hormone by somatotropes
What is PIH and what is its primary action on the anterior pituitary
Prolactin-inhibiting hormone
Inhibits synthesis and secretion of prolactin by lactotropes
What are the action of Thyrotrophin (TSH)
Uptake of Iodine
Synthesis and secretion of thyroglobulin (Tg) - acts as substrate for thyroxine (T4) and triiodothyronine (T3)
Increased blood flow in pituitary gland and hypertrophy and hyperplasia of it
What are the actions of corticotrophin (ACTH)
Stimulates synthesis and release of steroids (glucocorticoids and mineralocorticoids) from adrenal gland
Increases availability of cholesterol
Increases blood flow through adrenal gland
Hypertrophy and Hyperplasia of gland
Instead of LH and FSH being released by gonadotropes in females what is released in males
ICSH (interstitial cell stimulating hormone) and FSH
NB (ICSH is basically LH)
What are the actions of Growth hormone
Increased somatomedin production (from liver and muscles i think), protein synthesis, AA uptake by skeletal muscle and synthesis of cartilage
Name some factors that stimulate growth hormone secretion
Decreased blood glucose Decreased blood free fatty acids Increased blood amino acids Starvation/fasting Trauma, stress, excitement Exercise Deep sleep
Name some factors that inhibit growth hormone secretion
Increased blood glucose Increased blood free fatty acids Aging Obesity somatostatin growth hormone
What cells make up the posterior pituitary and describe their function/role
Mainly glial-like cells called pituicytes.
Pituicytes don’t release hormones, act as support structure for loads of terminal nerve fibres/endings from nerve tracts that originate in the supraoptic and paraventricular nuclei of the hypothalamus
What controls secretion from the posterior pituitary
Controlled by nerve signals that originate in the hypothalamus and terminate in the posterior pituitary
The bulbous nerve endings rlie on the surface of what in the posterior pituitary
capillaries
What posterior pituitary hormones are in the secretory granules of the nerve endings
- antidiuretic hormone/vasopressin
2. oxytocin
In which nuclei are ADH and oxytocin mostly formed
ADH in the supraoptic nuclei
Oxytocin in paraventricular nuclei
each nuclei can produce a bit of the other hormone
Why are oxytocin and ADH partially similar in their functions
Similar amino acid sequence
What is the primary stimulus for ADH and Oxytocin
ADH - high plasma osmolality
Oxytocin - descent of foetus
What is the main disorder caused by lack of ADH
Diabetes inspires
