3 Adrenal Gland

Question 1

what is the pathway in which cortisol is produced?

Answer 1

CRH released by hypothalamus which travels and stimulates anterior pituitary to release ACTH, adrenal gland then stimulated which secretes cortisol

Question 2

how does cortisol take part in negative feedback?

Answer 2

the cortisol produced acts upon pituitary to stop production of ACTH and hypothalamus to stop CRH

Question 3

what does ACTH stand for?

Answer 3

adrenocorticotrophin hormone

Question 4

what is the gene responsible for ACTH production?

Answer 4

POMC gene

Question 5

what is the transcription factor of the POMC gene?

Answer 5

Tpit

Question 6

how are different products produced from the POMC gene?

Answer 6

peptides produced from specific peptidase cleavage

Question 7

how does ACTH act on the adrenal gland?

Answer 7

on the MC2 receptor which is a G protein receptor in the adrenal gland

Question 8

how might a ACTH deficiency be caused?

Answer 8

mutations in Tpit causing less regulation of POMC gene expression

Question 9

what are the specific peptidases that cleave the POMC gene?

Answer 9

PC1 and PC2

Question 10

how is beta endorphin produced from the POMC gene?

Answer 10

POMC cleaved into N-POC and beta lipotropin, the beta lipotropin is then cleaved into gamma lipotropin and beta endorphin

Question 11

what hormones are produced from cleavage of N-POC?

Answer 11

ACTH and MSH

Question 12

how is the production of beta endorphin useful in production of ACTH?

Answer 12

produced in a stress response so acts as a pain reliever in fight or flight

Question 13

what effects does MSH have?

Answer 13

exerts effects through G protein receptors including MC1 receptor in skin to alter pigmentation

Question 14

how can ACTH production be tested for?

Answer 14

measure cortisol levels, synacthen tests, dexamethasone suppression test

Question 15

how does the dexamethasone test work?

Answer 15

it is an analogue of cortisol and so can be used to test the function of the negative feedback and test for excess ACTH levels

Question 16

what does the cortex of the adrenals produce?

Answer 16

glucocorticoids, mineralocorticoids, androgens

Question 17

what does the medulla of the adrenals produce?

Answer 17

catechalomines

Question 18

what is an example of a glucocorticoid?

Answer 18

cortisol

Question 19

what are the functions of glucocorticoids?

Answer 19

increase glycogenolysis and gluconeogenesis, sensitise arterioles to noradrenaline, initiation of diuresis

Question 20

what is an example of a mineralocorticoid?

Answer 20

aldosterone

Question 21

what are the functions of aldosterone?

Answer 21

also released with ACTH and causes reabsorption of sodium in distal tubules, alter distribution of sodium and potassium in the body

Question 22

what do androgens do?

Answer 22

promote formation of secondary sexual hair

Question 23

what does the zona fasciculate pathway form?

Answer 23

cortisol and corticosterone

Question 24

what does the zona golmerulosa pathway form?

Answer 24

aldosterone

Question 25

what does the zona reticular pathway form?

Answer 25

androstenedione

Question 26

what do all adrenal steroid production pathways come from?

Answer 26

cholesterol

Question 27

how is aldosterone production regulated?

Answer 27

when renin converts angiotensinogen to angiotensin I and then enzymes convert this to angiotensin II, this acts on adrenals to regulate aldosterone production

Question 28

what is Addisons disease?

Answer 28

hypofunction of adrenal gland caused by inflammation

Question 29

what are the causes of Addisons disease?

Answer 29

autoimmune adrenalitis, tuberculosis, adrenalectomy

Question 30

what are the less common causes of Addisons?

Answer 30

secondary tumour deposits, amyloiditis, adrenal haemorrhage

Question 31

what are the common clinical features of Addisons?

Answer 31

tiredness, weakness, weight loss, nausea, loss of body hair

Question 32

what is cushings disease?

Answer 32

hyperfunction of adrenal gland causing excess cortisol

Question 33

what is andrenogenital syndrome?

Answer 33

excess androgens

Question 34

what is conns syndrome?

Answer 34

excess aldosterone

Question 35

what causes conns syndrome?

Answer 35

adrenal adenoma, bilateral hypertrophy of zona glomerulosa cells

Question 36

what are the clinical features of conns syndrome?

Answer 36

hypertension, muscle weakness, polydipsia and polyuria

Question 37

what are the causes of Cushings syndrome?

Answer 37

pituitary hyper secretion of ACTH, adrenal adenoma/carcinoma, ectopic secretion of ACTH by tumours

Question 38

what are the clinical features of Cushing's syndrome?

Answer 38

truncal obesity, thinning of skin, purple striae, excessive bruising, muscle weakness

Question 39

what is the cause of cushings disease?

Answer 39

increased ACTH secretion, pituitary insensitive to normal levels of cortisol and so higher levels of cortisol needed in order to have negative feedback effect

Question 40

what is a secondary hyperaldosteronism?

Answer 40

involves activation of renin

Question 41

what are the common causes of a secondary hyperaldosteronism?

Answer 41

congestive cardiac failure, cirrhosis of the liver and nephrotic syndrome