Endocrinology: Hypothalamus/Pituitary Flashcards

1
Q
  • Hypothalamus - ____
  • anterior pituitary = ________
  • posterior pituitary = ________
  • ____ blood supply
A

CNS
adenohypophysis
neurohypophysis
dual

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2
Q

____ and _____ contain neurons that produce vasopressin and OT

A

supraoptic nucleus and paraventricular nucleus

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3
Q

OT acts on ____ and ____. stimulating what?

A

uterus(stimulates uterine contractions) and mammary glands (stimulates milk ejection during breast feeding)

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4
Q

vasopressin acts on ____ and ____, stimulating what?

A
  • nephrons in kidneys (increases permeability of distal and collecting tubules to H20)
  • arterioles throughout the body (causes vasoconstriction)
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5
Q

Neurohumoral reflex arcs:
vasopressin: _____ and ____
OT: ____ and ____

A
  • ECF osmolality and blood pressure/volume

- cervical stretch and suckling nipple

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6
Q

principle stimuli for the release of ADH: ___ and ____

A
  • increased osmolarity acts on hypothalamic osmoreceptors (dominant factor)
  • decreased arterial blood pressure detected by left atrial volume receptors (important only in large changes).
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7
Q

_____ effects on ADH secretion have a larger threshold for secretion, but once secreted have much quicker effects (because higher rate of ADH secretion)

A

volume effects (compared to osmolarity effects on ADH secretion)

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8
Q

describe the reflex pathway of suckling and OT release.

A

suckling stimulates mechanoreceptors in nipple, which stimulates the hypothalamus, which stimulates OT release from the posterior pituitary, OT into blood, stimulates contraction of myoepithelial cells surrounding alveoli, leading to milk ejection.

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9
Q

both ____ and ___ are positive feedback loops

A

OT release in suckling reflex and OT release in cervix stretching during pregnancy.

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10
Q

___ receptor very similar to OT receptor. Thus side-effect of pitocin could be ______

A

V1

hypertension

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11
Q

ADH - kidney acts through ___ receptor. ___ is second messenger

A

V2

cAMP

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12
Q

ADH - vascular acts through ____ receptor. ___ is second messenger.

A

V1

Calcium

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13
Q

oxytocin - smooth muscle acts through _____ receptor, ___ is second messenger.

A

OR

Calcium

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14
Q

_____ is most abundant hormone released by anterior pituitary

A

GH

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15
Q

TSH acts on ____, to release _____, causing ____

A

thyroid gland
T3 and T4
increased metabolic rate

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16
Q

ACTH acts on ____, to release _____, causing ____

A

adrenal cortex
cortisol
metabolic actions, stress response

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17
Q

Prolactin acts on _____, causing ____

A

mammary glands

breast growth and milk production/secretion

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18
Q

What are the two actions/pathways of GH?

A

1) GH acts on the liver to release IGF-1, leading to growth of bones and soft tissues
2) GH can be excitatory or inhibitory on adipose tissue, muscle, and/or liver; leading to metabolic actions

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19
Q

what would be some symptoms of a GH-secreting tumor?

A

hyperglycemia and increased lipolysis (diabetic-like effects)

20
Q

FSH in females: ______

FSH in males: ________

A

females: regulates gamete production. Stimulates growth and development of ovarian follicles, within which the ova, or eggs, develop (also promotes secretion of estrogen by ovaries).
males: regulates gamete production, FSH required for sperm production

21
Q

LH in females: _____

A

regulates ovarian secretion of the female sex hormones, estrogen and progesterone. LH also responsible for ovulation and luteinization.

22
Q

LH in males: ____

A

LH stimulates the testes to secrete the male sex hormone, testosterone.

23
Q

name the tropic hormones of the AP

A

GH, TSH, ACTH, FSH and LH

24
Q

name the direct acting hormones of the AP

A

PRL

25
Q

____, ____, ___, and ____ all act on their target organs by binding with GPCRs that activate cAMP second messenger pathways.

A

TSH, ACTH, FSH and LH

26
Q

____ and ____ act through the JAK/STAT pathway

A

GH and PRL

27
Q

____ is synthesized as part of a large precursor molecule known as pro-opiomelanocortin (POMC)

A

ACTH

28
Q

glycoprotein hormones of the AP

A

LH, FSH, and TSH

29
Q

somatomammotrophic hormones of the AP

A

GH and PRL

30
Q

what is name of the unique blood supple system of the adenohypophysis? describe it.

A

hypothalamic-hypophyseal portal system

  • nearly all blood supply that reaches AP, must first pass through hypothalamus
  • allows for direct transfer of hypophysiotropic releasing and inhibiting hormones to AP in high concentrations, without going into system circ.
    1) hypophysiotropic hormones produced by neurosecretory neurons in HYPO enter the HYPO capillaries.
    2) hypo capillaries rejoin to form the hypothalamic-hypophyseal portal system, which then branches into AP capillaries
    3) the hypophysiotropic hormones leave the blood across the AP capillaries.
    4) AP secretes appropriate hormone into these capillaries.
    5) AP capillaries rejoin to form a vein going into system circ.
31
Q

7 CNS hypophysiotropic hormones

A
TRH 
CRH
GnRH
GHRH
GHIH
PRH
PIH (dopamine)
32
Q

TRH stimulates ____

A

release of TSH and PRL

33
Q

CRH stimulates ___

A

release of ACTH

34
Q

GnRH stimulates _____

A

release of FSH and LH

35
Q

GHRH simulates _____

A

release of GH

36
Q

somatostatin (GHIH) inhibits _____

A

release of GH and TSH**

37
Q

PRH stimulates ____

A

release of PRL

38
Q

Dopamine inhibits _____

A

release of PRL

39
Q

how could you differentiate between secondary or tertiary cause of hyperthyroidism?

A

if lactation present, then tertiary. TRH from hypothalamus stimulates release of TSH and PRL*****

40
Q

Name some mechanisms that lead to control of releasing hormone secretion.

A
  • basal neurosecretory activity
  • neural inputs to neurosecretory nuclei
  • neural reflexes and rhythms
  • integration of internal/external stimuli
41
Q

give an example of long-looped feedback

A

cortisol feeding back on pituitary and hypothalamus

42
Q

give an example of short-looped feedback

A

ACTH feeding back on hypothalamus

43
Q

give an example of ultra-short looped feedback

A

CRH feeding back on hypothalamus

44
Q

what is the importance of negative feedback?

A
  • dampens extremes
  • maintains “final” hormone constant
  • nervous-endocrine reciprocity
  • prevent unintentional silliness
45
Q

of the tropic hormones from AP, which ones exert effects on non endocrine target cells in addition to stimulating secretion of other hormones?

A

FSH, LH, and GH