Lect 16 - Hypothalamus and Pituitary II

Question 1

What is the condition called when all pituitary hormones are not released?

Answer 1

panhypopituitarism

Question 2

Growth hormone deficiency in children leads to…

Answer 2

dwarfism

Question 3

What is a sign of gigantism on XR?

Answer 3

thickened soft tissue shadows

Question 4

There are three major effects of panhypopituitarism. What are they?

Answer 4

1) hypothyroidism
2) decreased glucocorticoids
3) decreased sex hormones

Question 5

What is the half-life of prolactin?

Answer 5

approximately 20 min

Question 6

What are the three major functions of prolactin?

Answer 6

1) breast development and milk production
2) maintains milk production (but not milk ejection)
3) inhibits ovulation!

Question 7

Estradiol leads to an increase in prolactin. What is the mechanism for this?

Answer 7

Estradiol inhibits DA which inhibits the hypothalamus. Disinhibition of hypothalamus leads to increased prolactin

Question 8

At what level does dopamine work in regards to prolactin release?

Answer 8

At the level of lactotrophs in the anterior pituitary

Question 9

What is the most common pituitary tumor?

Answer 9

Prolactinoma

Question 10

What causes the visual symptoms related to a pituitary tumor?

Answer 10

impingement on the optic nerve

Question 11

What is the common visual symptom caused by a pituitary tumor?

Answer 11

bitemporal hemianopsia

Question 12

A prolactinoma causes amenorrhea, how?

Answer 12

Release of prolactin causes inhibition of ovulation and cessation of menses

Question 13

What are the three main signs of excess prolactin release?

Answer 13

1) galactorrhea
2) decreased libido
3) inhibition of ovulation/spermatogenesis

Question 14

How does prolactin inhibit ovulation?

Answer 14

Inhibition of GnRH

Question 15

What is the medical/symptomatic treatment for a prolactinoma?

Answer 15

Bromocriptine

Question 16

How does bromocriptine exert its effects on prolactin?

Answer 16

DA agonist

Question 17

The posterior pituitary _______ two hormones: _______ and _______.

Answer 17

a) stores
b) oxytocin
c) ADH

Question 18

What is another name for ADH?

Answer 18

vasopressin

Question 19

Why is vasopressin abbreviated AVP?

Answer 19

short for arginine vasopressin

Question 20

What are the two triggers that activate the hypothalamus to produce ADH?

Answer 20

1) increase in ECF osmolarity

2) decrease in ECF volume

Question 21

What is the threshold for ADH release?

Answer 21

~280 mOsm

Question 22

What are the two main strategies the body has to decrease plasma osmolarity? Which is triggered first?

Answer 22

1) ADH release (triggered first)

2) thirst

Question 23

Where are V1 receptors found? V2 receptors?

Answer 23

V1Rs found in vascular smooth muscle cells

V2Rs found on principal cells in collecting duct

Question 24

What are the second messengers present in V1 receptors? V2 receptors?

Answer 24

V1Rs use IP3/DAG/Ca

V2Rs use cAMP

Question 25

Activation of V2Rs in the collecting duct leads to the incorporation of vesicles of which protein into the membrane?

Answer 25

AQP2 (aquaporin 2)

Question 26

What disorder is a deficiency of ADH?

Answer 26

diabetes insipidus

Question 27

How do you differentiate central DI from nephrogenic DI?

Answer 27

Water deprivation, then exogenous ADH; central DI will respond to ADH

Question 28

What are two symptoms of diabetes insipidus?

Answer 28

1) polyuria

2) polydipsia