Endocrinology (pit/panc/thy) (SUGER) Flashcards
what is the main purpose of the endocrine system
to release hormones directly into the blood
allows rapid adaptive changes
what is the pituitary gland aka
hypophysis
where is the pituitary gland located
depression in the SPHENOID bone at the base of the brain, just below the hypothalamus (sella turcica)
how is the pituitary gland connected to the hypothalamus
by the infundibulum (pituitary stalk), containing axons from hypothalamus neurones and small blood vessels
what is the pituitary gland composed of
2 adjacent lobes: anterior and posterior
what is sig about the embryology of the pituitary gland’s lobes
both develop from diff tissues before joining together
which hormone(s) has a positive feedback loop (pituitary gland)
oxytocin
which hormone(s) has a negative feedback loop (pituitary gland)
all but oxytocin
what is the role of the hypothalamus
homeostasis (thirst, sleep, temp)
- controls endocrine function via pituitary
what are the 5 hormones released by the hypothalamus
- CRH (corticotropin-releasing hormone)
- GHRH (growth hormone-releasing hormone)
- SST (somatostatin)
- TRH (thyrotrophin-releasing hormone)
- GnRH (gonadrotropin-releasing hormone)
- DA (dopamine)
what does CRH do
stimulates release of ACTH (adrenocorticotropic hormone)
what des GHRH do
stimulates GH release
what does SST do
inhibits release of GHRH
what does TRH do
stimulates release of TSH (thyroid-stimulating hormone)
what does GnRH do
stimulates release of LH/FSH
what does DA do
inhibits prolactin release (negative control by dopamine)
are there neural connections btwn hypothalamus and ant pit?
no
does the anterior pituitary gland have a blood supply
no
how does the ant pit gland receive blood?
- through a portal venous circulation from hypothalamus (superior hyphoseal)
- offers a local route for blood to be delivered directly
does the posterior pituitary gland have a blood supply
yes
what is a hypophysiotropic hormone
collective term for a hypothalamic hormone that regulates ant pituitary gland function
how many hormones does the anterior pituitary gland secrete
6
list the 6 peptide hormones the ant pit secretes
- FSH
- LH
- ACTH
- TSH
- Prolactin
- GH
(FLATP(I)G)
where is FSH prod
gonadotrophs
what does FSH do
stimulates ovarian follicle growth
what is the mnemonic for hormones of the anterior pituitary
FLATPIG
where is LH prod
gonadrotrophs
what does LH do
stimulates ovulation
where is ACTH prod
corticotrophs
what does ACTH do
stimulates adrenal cortex to secrete cortisol
where is TSH prod
thyrotrophs
what does TSH do
stimulates thyroid to release thyroxine (T3/T4) thus increasing metabolism
where is prolactin prod
lactotrophs
what does prolactin do
stimulates lactation, helps breast development
where is GH prod
somatotrophs
what does GH do
stimulates growth and protein synthesis
give an overview of what TRH does
TRH –> TSH –> incr release of T3/4 from thyroid –> increased metabolism
give an overview of what GnRH does
GnRH –> LH/FSH –> targets gonads to increase oestrogen, progesterone & testosterone
give an overview of what GHRH does
GHRH –> GH –> stimulates growth and protein synthesis
give an overview of what SST does
SST –> inhibits GH –> inhibits growth and protein synthesis