Adrenocortical Function and Dysfunction

Question 1

What is the embryological origin of the adrenal medulla?

Answer 1

Modified sympathetic ganglion (catecholamines/neurohormones)

Question 2

What is the embryological origin of the adrenal cortex?

Answer 2

Endocrine

Question 3

What are the functions mediated by CRH?

Answer 3

inflammation and immune responses; inhibition of appetite; signals onset of labour from placenta; linked to mood

Question 4

What is pro-opiomelanocortin (POMC)?

Answer 4

large protein that yields several bioactive peptides: ACTH (a. pit), beta-endorphin (a. pit), alpha-melanocyte-stimulating hormone (systemic ACTH)

Question 5

What is the function of beta-endorphin?

Answer 5

blocks pain perception

Question 6

What is the function of alpha-MSH?

Answer 6

decrease food intake, increase skin melanin

Question 7

What are melanocortins?

Answer 7

MSH hormones and ACTH

Question 8

What are the functions of cortisol?

Answer 8

essential; coping with long term stress; protects against hypoglycaemia by increasing catabolism of energy; permissive for glucagon and catecholamine actions

Question 9

What are the effects of long-term cortisol use?

Answer 9

inhibition of ACTH secretion and atrophy of cortisol-secreting cells - tf need to taper doses on and off so body can physiologically adapt

Question 10

A primary adrenal cortex disorder would be the result of

Answer 10

an adrenal cortex defect (primary = defect of the gland)

Question 11

A secondary adrenal cortex disorder would be a result of

Answer 11

defect of the hypothalamus or anterior pituitary

Question 12

What are the catecholamines?

Answer 12

Epinephrine (adrenal medulla only), norepinephrine, dopamine

Question 13

Why is epinephrine only made in the adrenal medulla?

Answer 13

phenylethanolamine-N-methyltransferase (PMNT) that converts norepinephrine to epinephrine is only found here

Question 14

What is the physiological result of hyperaldosteronism?

Answer 14

hypernatremia, hypokalemia, hypertension

Question 15

Cushing’s syndrome is what type of hypercortisolism?

Answer 15

Primary - adrenal cortex tumours secreting cortisol (ACTH independent)

Question 16

Cushing’s disease is what type of hypercortisolism?

Answer 16

Secondary - pituitary tumour secreting ACTH (ACTH-dependent)

Question 17

What is the most common cause of hypercortisolism?

Answer 17

Iatrogenic from prescription cortisol therapy

Question 18

What is adrenogenital syndrome?

Answer 18

Excess androgen and estrogen production due to lack of enzyme in the cortisol steroidogenic pathway shunting away from cortisol production towards sex hormones

Question 19

What is the effect of adrenogenital syndrome?

Answer 19

Inappropriate masculinisation (or early) of all but adult males

Question 20

What causes hyperglycaemia in Cushing’s syndrome?

Answer 20

Excess gluconeogenesis and glycogenolysis

Question 21

Decreased production of aldosterone (Addison’s, hypocortisolism) causes

Answer 21

K+ retention (cardiac arrhythmia) and Na+ and water depletion (hypotension)

Question 22

What causes salt and water retention in Cushing’s syndrome?

Answer 22

excess cortisol crossing over to react with mineralocorticoid receptors

Question 23

Secondary adrenal hyposecretion is caused by

Answer 23

abnormal hypothalamus or pituitary function causing decreased ACTH and cortisol production (aldosterone is normal)

Question 24

PMNT

Answer 24

phenylethanolamine-N-methyltransferase; converts norepinephrine to epinephrine in the adrenal medulla

Question 25

Pheochromocytomas

Answer 25

tumour of adrenal medulla causing hypersecretion of catecholamines and deadly prolonged hypertension

Question 26

Acute stress results in

Answer 26

activation of the fight or flight response

Question 27

Chronic stress results in

Answer 27

elevation of cortisol levels - this suppresses immune responses