w3 - endocrinology: basic princples

Question 1

steroids are derived from

Answer 1

cholesterol

Question 2

tyrosine and tryptophan derivatives examples 3

Answer 2

epinepgrine
thyroid hormones
melatonin

Question 3

major determinant of hormone conc

Answer 3

rate of secretion

- feedback loops

Question 4

raised TSH levels suggest

Answer 4

hypothyroid
hypothalamus sends TRH to ant.pit, who then sends TSH to thyroid. -ve feedback causes reduction in TRH, and so leads to hypothyroiid

Question 5

assessing pit function 8

Answer 5

9am cortisol 
FT4,FT3,TSH 
IGF1
LH,FSH,E2/Testosterone
U&E, plasma/urine osmolality
dynamic tests 
imagine \(MRI)

Question 6

outline the hypothalamic-pit-adrenal (HPA) axis

Answer 6

hypothalamus -> secretes CRH ->ant. pit -> secretes ACTH -> secretes cortisol (-ve feed on hypot and ant.pit) -> physiological effects

Question 7

9am cotiisol levels are tested at this time due to the lower serum levels t/f

Answer 7

false

high at this time

Question 8

9am cortisol levels arent enough to determine pit function, what then

Answer 8

dynamic testing

Question 9

determinants in measuring sex hormone axis

Answer 9

male - circadian rhythm

female - depends on menstrual cycle

Question 10

prolactin is secreted by lactotroph cells of the ant.pit. it is under tonic inhibition by ___ __

Answer 10

hypothalamic dopamine

Question 11

prl is mediated by

Answer 11

prolactin receptor (PRLR)

Question 12

dynamic testing occurs before or after imaging?

Answer 12

usually before

Question 13

cortisol defiency indicates an ___ insufficiency

Answer 13

adrenal

Question 14

2 examples of cortisol deficiency

Answer 14

primary adrenal failure - addisons disease

pituitary disease

Question 15

signs of cushings syndrome

Answer 15

cushingoig facies
acne
hirsutism 
abdominal striae and centripetal obesity 
interscapular + supraclavicular fat pads 
proximal myopathy 
osteoporosis 
hypertension 
impaired glucose tolerance

Question 16

4 types of cushings syndrome

Answer 16

pit-cushings
acth-independent cushings
ectopic acth (malignancy)
exogenous steroids

Question 17

tumour in the cortitroph cells of anterior pituitary lead to

Answer 17

cushings disease (well 70% reported caused by this0

Question 18

bilateral macronodular adrenal hyperplasia leads tbo

Answer 18

ACTH-independent cushings

Question 19

low dose dexamethasone suppression test is used to diagnose cushing. what happens? what is tested next, to determine source?

Answer 19

fail to suppress cortisol levels = cushings

measure ACTH

Question 20

if ATH is high, is adrenal likely to be the origin?

Answer 20

no
ACTH low = adrenal origin
if high, need to distinguish cushings disease and ectopic ACTH

Question 21

rrise in cortisol and ACTH on CRH test indicates ___ source

Answer 21

pituitary