hypothalamo-pituitary axis Flashcards

1
Q

describe the location of the hypothalamic nuclei

A

top to bottom, front to back

paraventricular
anterior
supraoptic

dorsomedial
ventromedial
arcuate

posterior
mamillary body (brain boob)

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2
Q

what regulates GNRH

A

kisspeptin

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3
Q

what does gnrh regulate

A

fsh and lh

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4
Q

what does adh have to do with acth

A

adh stimulates acth via short portal vessels between posterior and anterior pituitary

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5
Q

50% of pituitary gland cells are

A

GH cells

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6
Q

what does GH make

A

IGF-1

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7
Q

what inhibits prolactin

A

dopamine

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8
Q

what is prolactin stimulated by and when would you see hyperprolactinemia

A

TRH
hypothyroidism

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9
Q

what stimulated ACTH (2)

A

CRH, ADH via porrtal system

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10
Q

GH release is what style

A

pulsatile

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11
Q

what unexpected hormone stimulates GH

A

ghrelin

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12
Q

child with dwarfism and cretinism probably what mutation

A

PIT-1

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13
Q

gh released from what sort of cells

A

somatotroph

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14
Q

McCune Albright syndrome explain pathophysiology

A

oncogenic mutation in GNAS gene means alpha subunit in the GHRH receptor retains its activation->CAMP downstream function but LOSES its ATPase function so it no longer self-regulates and is always activated

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15
Q

what sort of receptors are endocrine receptors normally

A

GPCR

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16
Q

why do you only see eg mccune albright in mosaic form

A

germline mutation would not be compatible with life

17
Q

how many giants have recognised genetic element

18
Q

GH receptor is not a GPCR - what is it

A

dimerised cytokine receptor

19
Q

IGF is secreted by many tissues but where is the one that can be measured int he blood stream made

20
Q

what’s the relevance of GPR101

A

mutation prevalent in gigantism. related to GHRH stimulation but not sure how

21
Q

how do you recognise Addison’s pt just by looking at them

A

hyperpigmentation

22
Q

what is is ACTH made from

23
Q

if POMC is high and ACTH is therefore high, what subunit of ACTH will also be high and what will be the result

A

alpha MSH
hyper pigmenttation( Addison’s disease)

24
Q

red hair and fair skin

A

MC-1r variant

25
cortisol is... in teh morning and ...at night
high undetectable
26
when Cushing's disease
pituitary tumour secreting ACTH only
27
when would you need petrosal sinus/venous sampling
distinguish where excess ACTH is coming from in cushings disease. Eg lung tumour or overactive pituitary
28
glucocorticoid +++intake leads to
iatrogenic cushings
29
if you provide steroid tx for a pt, always give them...
steroid card
30
which four glycoprotein hormones have the same alpha unit but different beta units
LH, FSH, TSH, HCG
31
how do you stop FSH and LH in the case of breast/prostate cancer how on earth does it work
give GNRH analogue. Too much "GNRH" overwhelms the GPCR so it becomes desensitised and stops workign
32
FSH and LH are released by GNRH from the same cell so how can they be different levels at different times?
pulsatility. If GNRH every hour, LH high, FSH low If GNRH every three hours, other way round
33
Kallmann syndrome
can't smell, don't go through puberty
34
what is copeptin
like peptide C of adh precursor. can be measured
35
what is new name for diabetes insipidus
AVP deficiency
36