Neuroendocrine/Pituitary Lecture

Question 1

What is the hypothalamus’ role in the autonomic nervous system?

Answer 1

It’s huge!

It integrates informaiton for the control of the endocrine system and does so by controlling the pituitary gland

Question 2

What are the two parts of the pituitary gland?

Answer 2

anterior part: adenohypophysis

posterior part: neurohypophysis

Question 3

What connects the pituitary to the hypothalamus?

Answer 3

the median eminence

also called the infundibulum

Question 4

What two hormeons are secreted by the posterior pituitary?

Answer 4

vasopressin

oxytocin

Question 5

What neurons synthesize vasopressin and oxygotcin?

Answer 5

the magnocellular neurons of the supraotic and paraventricular nuclei

Question 6

What is another name for vasopressin?

Answer 6

anti-diuretic hormone (ADH)

Question 7

What 3 things triggers vasopressin secretion?

Answer 7

increased blood osmolarity (so increase in solute)

decreased blood volume (hypovolemia)

hypotension

Question 8

What is the effect of increased vasopressin secretion?

Answer 8

1. increased water resorption by the kidney (dilutes blood and increases blood volume)
2. vasoconstriction (increases blood pressure)

Question 9

What are the stimui for oxytocin secretion?

Answer 9

suckling (nursing)

uterine stimulation by a fetus

Question 10

What are the effects of oxytocin?

Answer 10

1. causes constriciotn of tubules in the breast, causing milk ejection reflex in response to suckling
2. Uterine contration to aid in delivery

Question 11

What hormones does the anterior pituitary secrete? THere’s7….

Answer 11

1. growth hormone
2. prolactine
3. thyroid-stimulating hormone
4. follicle stimulatin ghormone
5. lutenizing hormone
6. adrenocorticotropic hormone
7. beta-endorphin

Question 12

What are the two somatomammotropins secreted by the anterior pituitary?

Answer 12

growth hormonea nd prolactin

Question 13

What is the stimulus for growth hormone release and what is it’s main effect?

Answer 13

exercise, stress and sleep (80% released in sleep!)

growth ot tissue and metabolism

Question 14

What is the stimuli for prolactin release and what is its effect?

Answer 14

suckling and stress

development of mammary tissue and lactation (milk production)

Question 15

What do TSH, FSH, and LH have in common?

Answer 15

they are all glycoproteins with carbohydrate moieties

Question 16

What is the stimulus for thyroid-stimulating hormone secreiton and what is its effect?

Answer 16

exposure to cold temperature

causes increased thyroid hormone secretion, leading to increased cellular metabolism and heat production

Question 17

What is the effect of FSH in men and women?

Answer 17

men - spermatogenesis

women - development of ovarian follicle

Question 18

What are the affects of lutenizing hormone on men and women?

Answer 18

men - REQUIRED for spermatogenesis, stimulates testosterone

women - the trigger for ovulation, stimulates projecterone from the spent follicle

Question 19

What are the three hormones generated from cleavage of pro-opiomelanocortin (POMC)?

Answer 19

adrenocorticotropic hormone

beta-endorphin

melanocortin

Question 20

what is the stimuli for both adrenocorticotropic hormone and beta-endorphin release?

Answer 20

stress

Question 21

What is the effect of adrenocorticotropic hormone (ACTH)?

Answer 21

stimulates the release of cortisol form the adrenal cortex

Question 22

What is the effect of beta-endorphin?

Answer 22

is acts as an analgesic on the mu opioid receptor

Question 23

What test can be used to clinically assess anteiro rpituitary function?

Answer 23

do an insulin stress test

inject insulin, which will cuase blood glucose to go down. This is a stressful thing for the body, so you should see increased secretion of ACTH, Beta-endorphin, prolacting, and growht hormone

Question 24

What neuorns synthesize the hypothalamic releasing hormones?

Answer 24

the parvocellular neurons

Question 25

Where do the parvocellular neurons secrete the hypothalamic releasing hormones?

Answer 25

into the primary capillary bed within the median eminence, such that the releasing hormones can flow down to the anterior lobe via the hypophyseal portal vein.

Question 26

What are the 4 excitatory hypothalamic releasing hormones?

for TSH?

FSH and LH?

ACTH and beta-End?

GH?

Answer 26

TSH - thyrotropin releasing hormone

FSH/LH - gonadotropin releasing hormone

ACTH and beta-end - corticotropin releasing hormone

GH - growth hormone releasing hormone

Question 27

What hypothalamic releasing hormone decreases GH secretion?

Answer 27

somatostatin

Question 28

What hormone’s secretion is inhibited by dopamine from the hypothalamus?

Answer 28

prolactin

Question 29

What hormonal changes would you expect to see after a pituitary stalk section?

Answer 29

increase in prolactin

decrease in everything else

Question 30

What hormone is lost in diabetes insipidus? how?

Answer 30

vasopressin

you have either head trauma or autoimmune disorders that cause desctruction of the magnocellular neurons

Question 31

What are the two main symptoms of diabetes insipidus and why?

Answer 31

ultimately, you dont have vasopressin, so you don’t respond to low blood pressure, hypovolemia or osmolarity in the same way

this means you have polyuria - because ou can’t retain water

polydipsia - because you have to make up for the volume loss somehow

Question 32

How do you treat diabetes insipidus?

Answer 32

you have to have a way to replinish the vasopressin without causing severe vasoconstriciton - you want one that will just act on the kdiney

desamino vasopressin

Question 33

An overabundance of what hormone will cause galactorrhea/amenorrhea?

Answer 33

prolactin

Question 34

WHat is the pituitary of galactorrhea - amenorrhea?

Answer 34

a pituitary timor which produces prolactin (usually a microadenoma)

this decreases the release of FSH and LH from the anterior pituitary

Question 35

What are the treatment options for galactorrhea-amenorrhea?

Answer 35

1. surgery to remove the tumor and thus decrease prolactin
2. give a dopamine receptor agonist like bromocryptine to decrease prolactin release