Neuroendocrine function Flashcards
What system does the hypothalamus regulate?
Stress response, growth, reproduction, fluid regulation and metabolism
What brain region facillitate “the endocrine system’s link to the NS?”
The hypothalamus
How many grams are the hypothalamus app. in humans?
4 g
What are the difference between the posterior and anterior pituitary?
Posterior: directly innervated by hypothalamic neurons
Anterior: hypothalamic neurons secrete hormones in blood vessels above the pituitary –> hormones transported via blood to anterior pituitary
What hormones does the posterior pituitary release?
Oxytocin and ADH
What hormones does the anterior pituitary release?
TSH, ACTH, FSH and LH, GH, prolactin, and endorphines
What are the two types of neurons that signal to the pituitary, and where are they located and what part of the pituitary do they signal to?
Magnocellular: located in paraventricular nuclei (PVN) and supraoptic nuclei (SON), signal to posterior
Parvicellular: located in PVN, signal to anterior via the pituitary portal vessles in the median eminence
What hormones does the magnocellular neurons release?
OT, AVP and NP
What hormones does the parvicellular neurons release?
CRH, TRH, GnRH, GHRH, SS, and DA
What is the HPA axis?
Stress axis: Hypothalamus –> pituitary –> adrenals
Describe the HPA axis.
CRH released from hypothalamus to the blood vessels in the median eminence –> ACTH released from the anterior pituitary –> cortisol released from the adrenal cortex –> target tissue
Describe the negative feed-back loops of the HPA axis.
Cortisol inhibits ACTH release from anterior pituitary and CRH release from the hypothalamus
Describe the effects of cortisol released in the HPA axis.
- increases blood glucose by increasing gluconeogenesis
- anti-inflammatory effects
- augments catecholamine response
What are the disturbances of the HPA axis called?
Hyper: cushing
Hypo: addison
What are the stimuli for the HPA axis, internal vs external?
Internal: physical, biochemical, emotional
External: diurnal/circadian rhythms
What is the HPT axis?
Hypothalamus –> pituitary –> thyroid
Describe the HPT axis.
TRH released from hypothalamus to the blood vessels in the median eminence –> TSH released from the anterior pituitary –> T4/T3 released from the thyroid –> increase in metabolism
What are the HPT axis disturbances called?
Hypo: e.g., hashimoto’s disease
Hyper: e.g., Grave’s disease
Describe the growth hormone releasing pathway.
GHRH released from the hypothalamus to the blood vessels in the median eminence –> GH released from anterior pituitary –> IGF-1/2 released from liver
Describe the cellular signaling cascade for the release of GH.
GHRH binds to GHRH-Rs on cells in anterior pituitary (GPCR) –> AC activation –> ATP –> cAMP –> PKA activation –> Ca2+ influx –> GH is released
What are the function of GH?
GH binds to GH-Rs on liver cells (cytokine receptor) –> metabolic actions + transcriptional actions –> IG-F1/2 –> induce growth on bones
GH also binds directly to receptors on the bones
