Hypothalamus and Pituitary

Question 1

Where is rathke’s pouch located?

Answer 1

the anterior pituitary

Question 2

What are the three parts of the anterior lobe of the pituitary?

Answer 2

pars distalis, pars tuberalis, pars intermedia

Question 3

What are the parts of the posterior lobe of the pituitary

Answer 3

pars nervosa, infundibulum, infundibular stalk, and median eminence

Question 4

Where is CRH synthesized and what is its main function

Answer 4

Corticotropin releasing hormone is synthesized in the hypothalamus and stimulates cortictropes in the pituitary to secrete ACTH

Question 5

Where is TRH synthesized and what are the 3 main effects

Answer 5

thyrotropin releasing hormone is synthesized in the hypothalamus and its functions are:
-stimulate thyrotropes in anterior pituitary to secrete TSH
-stimulates lactotropes in anterior pituitary to secrete prolactin
-stimulates melanotropes in pars intermedia to secrete POMC, which is processed into ACTH

Question 6

Where is GHRH synthesized and what is its function

Answer 6

Growth hormone releasing hormone is synthesized in the hypothalamus and stimulates somatotropes in anterior pituitary to secrete GH

Question 7

What is the function of somatostatin in the pituitary

Answer 7

it is released by hypothalamic neurons into the anterior pituitary and inhibits somatotrope secretion of growth hormone

Question 8

Where is GnRH synthesized and what is its function

Answer 8

gonadotropin releasing hormone is synthesized in the hypothalamus and stimulates gonadotropes in the anterior pituitary to secrete FSH and LH

Question 9

What is the function of dopamine in the anterior pituitary

Answer 9

dopamine is released by hypothalamic neurons and inhibits lactotropes in the pars distalis and melanotropes in the pars intermedia

Question 10

The hypothalamo-hypophyseal portal system goes to which part of the pituitary

Answer 10

the pars distalis not the intermedia

Question 11

What are the three main regulatory mechanisms of the anterior pituitary

Answer 11

-hypothalamic trophic hormones
-negative feedback
-paracrine secretions by cells in pituitary

Question 12

How would you distinguish the pars distalis from the pars intermedia histologically?

Answer 12

The pars intermedia DOES NOT have acidophils

Question 13

The basophils of the pars distalis include which secretory cells? what products do they produce

Answer 13

-corticotropes: ACTH
-thyrotropes: TSH
-gonadotropes: LH, FSH

Question 14

The basophils of the pars intermdiea include which secretory cell(s)? what products do they produce?

Answer 14

-melanotropes: ACTH and MSH

Question 15

The acidiphis of the pars distalis include which secretory cells? what products do they produce?

Answer 15

-Somatotropes: GH
-Lactotropes: prolactin

Question 16

The acidiphils of the pars intermedia include which secretory cells? what products do they produce

Answer 16

trick question, the pars intermedia DOES NOT have acidophils

Question 17

Define trophic hormones

Answer 17

hormones that regulate other endocrine glands

Question 18

Which type of pars distalis cell secrete tropic hormones?

Answer 18

the basophils

Question 19

True/False: acidophls produce hormones that act directly on target organs

Answer 19

true

Question 20

True/False: POMC is produced by both corticotrophs and melatontrophs

Answer 20

true

Question 21

What is the main difference between canine cushings and equine PPID

Answer 21

canine cushings, if the tumor is in the pituitary, will have the tumor in the pars distalis while equine PPID is caused by a tumor in the pars intermedia

Question 22

True/False: oxytocin and ADH are produced in the pars nervosa

Answer 22

false they are produced by the hypothalamus

Question 23

What are herring bodies?

Answer 23

dilated portion of hypothalamic axons that act as a neurosecretory vesicle storage site where the hormones are bound to neurophysin

Question 24

You see a nucleus in the pars nervosa, what cell does it belong to?

Answer 24

pituicyte (aka glial cell/astrocyte of the pituitary)
or endothelial cell

Question 25

What are the two main regulatory points of ADH?

Answer 25

extracellular fluid volume and osmolarity

Question 26

Briefly explain how ADH works

Answer 26

increases the number of aquaporins in the apical membrane of epithelial cells in the distal tubule and collecting ducts of the kidney

Question 27

What are the two main effects of oxytocin

Answer 27

contraction of uterine smooth muscle and mammary gland myoepithelial cells

Question 28

What are the 6 anterior pituitary hormones?

Answer 28

FSH, LH, ACTH, TSH, GH, Prolactin

Question 29

True/False: all anterior pituitary hormones are tropic except for prolactin

Answer 29

true

Question 30

True/False: only the ACTH product of POMC is biologically active

Answer 30

false,

Question 31

What important pituitary hormone has a circadian pattern of secretion

Answer 31

ACTH

Question 32

True/False: hormones from the anterior pituitary do not inhibit their own secretion

Answer 32

false

Question 33

What is the role of IGF-1 in growth hormone secretion? where is it secreted from

Answer 33

IGF-1 is secreted by the liver and stimulates the release of somatostatin which inhibits the secretion of growth hormone by the pituitary

Question 34

decreased glucose concentration, fatty acid concentration, exercise, stress, fasting/starvation all ____ growth hormone secretion

Answer 34

stimulate

Question 35

somatostatin, growth hormone, and pregnancy all ___ growth hormone secretion

Answer 35

inhibit

Question 36

What are some of the major effects of growth hormone

Answer 36

-stimulates the production of IGF-1, stimulates protein synthesis, stimulates lipolysis, inhibits tissue uptake and utilization of glucose