Neuroendocrine function

Question 1

What system does the hypothalamus regulate?

Answer 1

Stress response, growth, reproduction, fluid regulation and metabolism

Question 2

What brain region facillitate “the endocrine system’s link to the NS?”

Answer 2

The hypothalamus

Question 3

How many grams are the hypothalamus app. in humans?

Answer 3

4 g

Question 4

What are the difference between the posterior and anterior pituitary?

Answer 4

Posterior: directly innervated by hypothalamic neurons
Anterior: hypothalamic neurons secrete hormones in blood vessels above the pituitary –> hormones transported via blood to anterior pituitary

Question 5

What hormones does the posterior pituitary release?

Answer 5

Oxytocin and ADH

Question 6

What hormones does the anterior pituitary release?

Answer 6

TSH, ACTH, FSH and LH, GH, prolactin, and endorphines

Question 7

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?

Answer 7

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

Question 8

What hormones does the magnocellular neurons release?

Answer 8

OT, AVP and NP

Question 9

What hormones does the parvicellular neurons release?

Answer 9

CRH, TRH, GnRH, GHRH, SS, and DA

Question 10

What is the HPA axis?

Answer 10

Stress axis: Hypothalamus –> pituitary –> adrenals

Question 11

Describe the HPA axis.

Answer 11

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

Question 12

Describe the negative feed-back loops of the HPA axis.

Answer 12

Cortisol inhibits ACTH release from anterior pituitary and CRH release from the hypothalamus

Question 13

Describe the effects of cortisol released in the HPA axis.

Answer 13

• increases blood glucose by increasing gluconeogenesis
• anti-inflammatory effects
• augments catecholamine response

Question 14

What are the disturbances of the HPA axis called?

Answer 14

Hyper: cushing
Hypo: addison

Question 15

What are the stimuli for the HPA axis, internal vs external?

Answer 15

Internal: physical, biochemical, emotional
External: diurnal/circadian rhythms

Question 16

What is the HPT axis?

Answer 16

Hypothalamus –> pituitary –> thyroid

Question 17

Describe the HPT axis.

Answer 17

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

Question 18

What are the HPT axis disturbances called?

Answer 18

Hypo: e.g., hashimoto’s disease
Hyper: e.g., Grave’s disease

Question 19

Describe the growth hormone releasing pathway.

Answer 19

GHRH released from the hypothalamus to the blood vessels in the median eminence –> GH released from anterior pituitary –> IGF-1/2 released from liver

Question 20

Describe the cellular signaling cascade for the release of GH.

Answer 20

GHRH binds to GHRH-Rs on cells in anterior pituitary (GPCR) –> AC activation –> ATP –> cAMP –> PKA activation –> Ca2+ influx –> GH is released

Question 21

What are the function of GH?

Answer 21

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