Neuroendocrinology

Question 1

What are neuroendocrine cells?

Answer 1

Neurosecretory cells that release signal molecules from their synaptic terminals into the blood

Question 2

What controls neuroendocrine cells?

Answer 2

Sympathetic transmission from presynaptic neurons

Question 3

What are the steps in development of the pituitary gland?

Answer 3

Evagination of the floor of third ventricle

Evagination of the oral ectoderm

Rathkes pouch is pinched off
Merge

Question 4

What is the neural ectoderm?

Answer 4

Evagination of the floor of the third ventricle

Question 5

What is rathke’s pouch?

Answer 5

Evagination of oral ectoderm

Question 6

What do parvocellular nuclei do?

Answer 6

Release hormones to the capillaries of median eminence

Question 7

Where do the median eminence capillaries come from?

Answer 7

Superior hypophysial artery

Question 8

Where do the capillaries of medial eminence lead to?

Answer 8

Portal veins to the anterior pituitary

Question 9

What do hormones released from the parvocellular nuclei do?

Answer 9

Regulate endocrine secretion from the anterior pituitary

Question 10

What do the magnocellular nuclei do?

Answer 10

Project to posterior pituitary and release hormones to the capillaries supplied by the inferior hypophysial artery

Question 11

Where are the hormones stored in the posterior pituitary gland?

Answer 11

Hypothalamic neuron terminals

Question 12

When/ where are oxytocin and vasopressin released?

Answer 12

Under neural control into hypophysial capillaries -> inferior hypophysial vein

Question 13

What increases growth hormone secretion?

Answer 13

GH releasing hormone

Ghrelin

Question 14

Where is GH releasing hormone secreted?

Answer 14

Hypothalamic parvocellular neuroendocrine cells

Question 15

What secretes ghrelin?

Answer 15

Endocrine cells of the stomach

Question 16

What is the other function of ghrelin? (Ie not growth hormone stimulator)

Answer 16

Powerful appetite stimulator

Question 17

What is growth hormone secretion decreased by?

Answer 17

GH inhibiting hormone

Question 18

Where is GH inhibiting hormone secreted from?

Answer 18

Hypothalamic parvocellular neuroendocrine cells

Question 19

What is another term for GH inhibiting hormone?

Answer 19

Somatostatin

Question 20

What is the GH negative feedback controlled by?

Answer 20

GH already in circulation

IGF-1 in circulation (released by the liver in response to GH)

Question 21

What does IGF-1 inhibit?

Answer 21

Hypothalamus and pituitary gland

Question 22

What does GH do in adipose tissue?

Answer 22

Increases lipolysis

Question 23

What does GH do in liver tissue?

Answer 23

Increases gluconeogenesis and IGFs

Question 24

What does GH do in muscle tissue?

Answer 24

Increases protein synthesis

Question 25

What does IGF release lead to?

Answer 25

Increase in somatic cell growth, chondrocyte function and bone modelling/ remodelling

Question 26

What does IGF stand for?

Answer 26

Insulin growth factor

Question 27

What do GH levels look like throughout the day in young adults?

Answer 27

Small peaks in the day and a huge spike in the middle of the night

Question 28

What happens to the GH levels throughout the day in older adults?

Answer 28

Same as young adults just smaller peaks

Question 29

How does your mean circulating GH conc change throughout life?

Answer 29

Increases after birth, constant through childhood, peaks in puberty and then slowly decreases as you age

Question 30

What is is called when you have an excess of GH?

Answer 30

Acromegaly

Question 31

What is acromegaly generally caused by?

Answer 31

Pituitary adenoma

Question 32

What are the metabolic consequences of acromegaly?

Answer 32

Excess GH -> insulin resistance
Impaired glucose tolerance and hyperinsulinaemia
Possibly also dyslipidaemia