2.4.2 Hypothalamus-Pituitary Physiology

Question 1

What is unique about the circulation to the pars distalis?

Answer 1

Open circulation (two capillary plexuses)

Question 2

What upregulates/downregulates activity of the thyrotroph in the anterior pituitary?

Answer 2

Upregulate: TRH (g_alphaq, PLC, PKC, Ca++)

Downregulate: SRIF (g_alphai, decreased AC, decreased Ca++)

Question 3

What upregulates/downregulates activity of the somotatroph in the anterior pituitary?

Answer 3

Upregulate: GHRH (G_alphas, AC, cAMP, Ca++)

Downregulate: SRIF (G_alphai, decreased AC, decreased Ca++)

Question 4

What do these abbreviations stand for?

Answer 4

VD: ventral diencephalon

OE: Oral ectoderm

RP: Rathke’s pouch

INF: infundibulum

Question 5

What are two different stimuli for oxytocin production? What are two sites of action of oxytocin? Where is oxytocin produced?

Answer 5

Stimuli: Cervical strech, suckling

Sites of Action: Uterus, mammary glands

Site of production: Paraventicular (majority)

Question 6

Describe the txn factor cascade in the three layers: ventral diencephalon, mesenchyme, oral ectoderm

Answer 6

Question 7

What are some of the hypothalmic releasing and inhibiting hormones?

Answer 7

Question 8

What tissue(s) is most directly regulated by the hormones of each anterior pituitary cell type?

Answer 8

Corticotropes: Adrenal cortex

Somatotropes: Liver/muscle/adipose

Lactotropes: Mammary gland

Thyrotropes: Thyroid

Gonadotropes: Ovary/testis

Question 9

Identify these structures.

Answer 9

Question 10

Describe the txn factor cascade leading to the 5 different cell types of the anterior pituitary. Also, identify whether POU1F1(PIT1) and/or GATA2 are expressed.

Answer 10

Question 11

Name three important txn factors in the development of the pituitary?

Answer 11

Hesx1/Rpx, Prop1, Pit1

Question 12

What is Ashley Falkner’s favorite television show?

Answer 12

The Bachelor

Question 13

What are the clinical manifestations of various genetic dysfunctions?

(I would focus on the red)

Answer 13

Question 14

Where are fenestrated caplliaries present b/t the hypothalmus and pituitary gland?

Answer 14

Median eminence

Question 15

What upregulates/downregulates the activity of the mammotroph(lactotroph) in the anterior pituitary?

Answer 15

Upregulate: PRH

Downregulate: Dopamine (G_alphai, decreased AC, decreased Ca++)

DOPAMINE HAS DOMINATE NEGATIVE CONTROL

Question 16

CRH upregulates what?

Answer 16

Increases ACTH, and MSH

Question 17

What are some ways to modify neuronal inputs?

Answer 17

Exogenous rhythms, environment, behavior

Question 18

Other than the five hormone producing cells, what is an important cell type found in the anterior pituitary?

Answer 18

Folliculo-stellate cells (stem cells)

Question 19

What would the effect on development of the anterior pituitary if there was a mutation in PROP1?

Answer 19

Question 20

Which txn factors involved in the development of the anterior pituitary are associated with human dz?

Answer 20

HESX1, LHX3, PROP1, TBX19, PIT1, SF1

Question 21

What stimulates ADH production? What antagonizes ADH production?

What are the effects of ADH after acting on the kidney?

Answer 21

Stimulate: Increased plasma osmolality

Antagonize: Increased plasma volume

Effects: Increased plasma volume, decreased plasma osmolality

Question 22

What are the two types of magnocellular neurons send hormones to the posterior pituitary to be stored?

Answer 22

Supraoptic and paraventricular nuclei

Question 23

T3/T4 sending negative feedback to the anterior pituitary (TSH) is an example of what?

Answer 23

Target endocrine gland hormone feedback

Question 24

Which portion of the pituitary is comprised of the pars nervosa? pars distalis?

Answer 24

Pars nervosa: Posterior (neuronal)

Pars distalis: Anterior (non-neuronal)

Question 25

What upregulates activity of the corticotroph in the anterior pituitary?

Answer 25

CRH (G_alphas, AC, cAMP)

Question 26

What proteins bind onto OXY and ADH during their transport to posterior pituitary?

Answer 26

ADH: Neurophysin II

OXY: Neurophysin I

Question 27

What are the five cell types of the anterior pituitary and their main hormone?

Answer 27

Question 28

What are some of the negative feedback loops onto the hypothalmus/pituitary?

Answer 28

Question 29

What are the different types of feedback loops and where they work within the H-P-A axis?

Answer 29

Question 30

Name this syndrome.

Answer 30

Kallmann Syndrome

Question 31

Summarize the target and action of the major hormones released from the anterior pituitary.

Answer 31

Question 32

What upregulates the activity of the gonadotroph in the anterior pituitary?

Answer 32

GnRH (G_alphaq, PLC, PKC, Ca++)

Question 33

What would be the result of a mutation of PIT1 in the development of the anterior pituitary?

Answer 33

Question 34

An infarct of the pituitary is known as what? What is its effects on the various cell types in the anterior pituitary?

Answer 34

Sheehan’s

Effect: A decrease in all five cell types

Question 35

What does the portal system allow within the pituitary gland?

Answer 35

Low volume, high concentration,

(pulsatile) (rhythms)