Pituitary Physiology Flashcards Preview

Endocrine > Pituitary Physiology > Flashcards

Flashcards in Pituitary Physiology Deck (55)
Loading flashcards...
1
Q

Pituitary sits in the _____

A

sella tursica

2
Q

Adenohypophysis

A

anterior pituitary

3
Q

Neurohypophysis

A

posterior pituitary

4
Q

Deficiency in ____ or ____ transcription factors will result in panhypopituitary.

A

Prop1 or Pit1

5
Q

Somatotrope secretes ____

A

growth hormone

6
Q

Thyrotrope secretes ____

A

thyrotropin/TSH

7
Q

Lactotrope secretes ____

A

prolactin

8
Q

Gonadotrope secretes ____

A

LH/FSH

9
Q

Corticotropesecretes ____

A

ACTH

10
Q

Glycoprotein AP hormones

A

TSH/LH/FSH: same alpha subunit, different beta subunit

11
Q

ACTH is derived from ____

A

POMC

12
Q

T/F Both GH and prolactin can activate the prolactin receptor

A

T –> structural homology

13
Q

Which hormone? Stimulates secretion of IGF1 from liver and stimulates lipid and CHO metabolism.

A

GH

14
Q

Which hormone? Stimulates synthesis and secretion of thyroid hormones and regulates thyroid cell proliferation and survival.

A

TSH

15
Q

Which hormone? Stimulates synthesis and secreetion of adrenal cortex steroids and proliferation and survival of adrenal cortex cells.

A

ACTH

16
Q

Which hormone? Stimulates milk production.

A

Prolactin

17
Q

Which hormone? Stimulates ovulation and progesterone synthesis. Gametogenesis in males and synthesis/secretion of testosterone.

A

LH

18
Q

Which hormone? Stimulates estrogen synthesis and follicular growth. Spermatogenesis in males.

A

FSH

19
Q

Which hormones share the same alpha subunit in their structure?

A

TSH/LH/FSH

20
Q

Loss of ______ by target hormones results in pituitary trophic hormone hypo/hypersecretion and hypo/hyperplasia of pituitary cells as seen in severe hypothyroidism or hypoadrenalism.

A

feedback inhibition –> hypersecretion and hyperplasia

21
Q

Ultradian rhythm

A

burst/spike of hormon secretion that can be superimposed on circadian rhythm–> important for things like reproduction

22
Q

Hypothyroidism caused by thyroid gland destruction can lead to hypertrophy of which gland?

A

Anterior pituitary

23
Q

Hypothalamic-Pituitary-Adrenal Axis

A

Hypothalamic CRH (stimulatory trophic factor) –> AP ACTH –> Adrenal Cortex cortisol –> feedback to hypothalamus and pituitary

24
Q

T/F melanotropin and ACTH are derived from the same molecule

A

T –> cleaved from POMC (pro-opiomelanocortin)

25
Q

Stimuli for CRH secretion

A

stress, hypoglycemia, anxiety, depression, alpha/beta adrengergic agonists –> peaks before waking

26
Q

Inhibitor of ACTH

A

cortisol

27
Q

What laboratory picture is expected in a patient with excessive cortisol production by an adrenal tumor?

A

High cortisol, low ACTH

28
Q

Student is studying for at test at 1 am. What is his cortisol profile?

A

high ACTH, high cortisol –> stress can overcome circadian rhythm

29
Q

Student is asleep at 1 am. What is his cortisol profile?

A

low ACTH, low cortisol

30
Q

Hypothalamic-Pituitary-Growth Hormone axis

A

hypothalamic ghrh –>pituitary GH –>liver IGF1–> with negative feedback from hypothalamic somatostatin, liver IGF1 and pituitary GH

31
Q

Stimulators of GHRH

A

hypoglycemia, dietary protein, exercise

32
Q

GHRH is inhibited by ____

A

IGF1 and GH

33
Q

T/F SST are present in many tissues

A

T –> hypothalamus, GI tract, pancreas

34
Q

Somatostatin inhibits:

A

TSH, PRL, glucagon, insulin, and GH release

35
Q

Growth hormone

A

stimulates post natal growth indirectly via IGF1–> declines from puberty onward, pulsatile secretion

36
Q

GH half life

A

6-20 minutes

37
Q

What is the measure of GH production?

A

IGF1 –> cannot get accurate GH measurement because of short half life and b/c amplitude and frequency of pulses are affected by many variables

38
Q

Which physiologic process will lead to a decrease in GH production?

A

reduction in GHRH, increase in somatostatin, increase in IGF1

39
Q

Prolactin axis

A

breast neural stimulus –>hypothalamic PRF –> pituitary prolactin –> mammary gland //hypothalamic dopamine inhibits the pituitary, pituitary prolactin inhibits hypothalamic GnRH, and ovarian E2 stimulates the pituitary

40
Q

Inhibitory feedback in prolactin axis

A

Milk does not feedback!

41
Q

prolactin is inhibited by

A

dopamine

42
Q

prolactin negatively regulates ______ via hypothalamus GnRH

A

FSH/LH

43
Q

T/F high prolactin negatively regulates HPG axis and can explain amenorrhea in a nursing woman

A

T

44
Q

Why do we treat hyperprolactinemia in men?

A

to treat hypogonadism (via GnRH)

45
Q

HPG axis

A

hypothalmic GnRH –> pituitary FSH/LH –> positive/negative feedback from ovary/testis estrogens (on both hypothalamus and pituitary), negative feedback from inhibin (on pituitary), negative testosterone/progesterone feedback on hypothalamus

46
Q

Effect of constant GnRH infusion

A

inhibition of LH/FSH –> which normally are pulsatile

47
Q

LH effect in males

A

stimulates androgen synthesis

48
Q

LH effect in females

A

ovulation, progesterone synthesis

49
Q

FSH effect in males

A

spermatogenesis

50
Q

FSH effect in females

A

follicle growth, estrogen synthesis

51
Q

Which laboratory picture is characteristic of physiologic menopause?

A

low estrogen, high fsh, high lh

52
Q

hypothalamic-pituitary-thyroid axis

A

Hypothalamic TRH –> Pituitary TSH –> Thyroid T3/T4- -> negative feedback on hyptothalamus and pituitary // hypothalamic somatostatin also opposes TRH

53
Q

TRH

A

sitmulates TSH and prolactin

54
Q

When T3 is high/low, TRH receptors decrease and thus response of thyrotrope to TRH decreases and thus TSH increases/decreases

A

low and decreases

55
Q

Inhibitory hypothalamic factors

A

somatostatin and dopamine