hormone axis physiology Flashcards
what does anterior pituitary release
TSH ACTH FSH + LH GH Prolactin
what does posterior pituitary release
oxytocin
ADH
what does hypothalamus release
TRH CRTH GnRH PRH GHIH dopamine
thyroid axis
hypothalamus releases TRH which stimulates Ant. pituitary to release TSH
thyroid then produces T3 and T4
T3 and T4 suppress TRH and TSH release - negative feedback
where is cortisol secreted from
adrenal glands
release is controlled by hypothalamus
when does cortisol peak
diurnal variation
peaks in early morning and lowest late evening
adrenal axis
hypothalamus releases CRH, stimulates anterior pituitary to release ACTH
adrenal glands then release cortisol
cortisol feedbacks to supress CRH and ACTH release
cortisol actions
inhibit immune system inhibit bone formation raises blood glucose increases metabolism increases alertness
growth hormone axis
GHRH released from hypothalamus, Anterior pituitary releases GH
GH stimulated IGF-1 from liver
actions of growth hormone
stimulate muscle growth
increase bone density
stimulate cell regeneration and reproduction
stimulate growth of internal organs
what secreted PTH
parathyroid glands
what stimulates PTH release
low serum calcium
also
- low magnesium
- high phosphate
what does PTH do
- increase osteoclast activity
- inc kidney calcium reabsorption
- stimulates kidney to convert VitD3 to active VitD which promotes small intestine Ca absorption
what does PTH act to do
raise serum calcium
what does aldosterone do
inc sodium reabsorption
inc potassium secretion
inc hydrogen secretion
–> acts to increase bP
