Adrenal

Question 1

drainage of the adrenal glands?

Answer 1

left adrenal vein drains into left renal vein

right adrenal drains directly into inferior vena cava

Question 2

adrenal medulla?

Answer 2

modified sympathetic ganglion derived from neural crest tissue and secretes catecholamines (epinephrine, norepinephrine & dopamine)

Question 3

adrenal cortex?

Answer 3

true endocrine gland derived from mesoderm and secretes 3 classes of steroid hormone:

mineralocorticoid - aldosterone
glucocorticoids - cortisol
sex steroids - testosterone

Question 4

3 concentric cortex zones?

Answer 4

zona glomerulosa - aldosterone
zona fascilculata - glucocorticoids
zona reticularis - sex hormones

Question 5

how does cortisol work?

Answer 5

bins to glucocorticoid receptors that are present on nearly all nucleated cells

the hormone-receptor complex migrates to nucleus and binds to DNA to alter gene expression, transcription and translation

permissive action on glucagon

Question 6

plasma cortisol levels?

Answer 6

peak is 6-9am and Lull is around midnight

Question 7

actin of cortisol on glucose metabolism?

Answer 7

gluconeogenesis
proteolysis
lipolysis
decreases insulin sensitivity

cortisol ultimately acts to oppose the actions of insulin

Question 8

additional non-glucocorticoid actions of cortisol?

Answer 8

negative effect on Calcium balance
impairment of mood/cognition
permissive effect on norepinephrine (HT in Cushing’s)
suppression of the immune system

Question 9

What is aldosterone and what does it do?

Answer 9

Aldosterone is a mineralocorticoid and acts on the distal tubule of the kidney and increases reabsorption of Na and excretion of K ions

Question 10

what controls aldosterone?

Answer 10

RAAS

Question 11

Increased/Decreased aldosterone leads to?

Answer 11

Increased leads to Na retention and K depletion resulting in increased blood volume and increase BP

decreased aldosterone leads to Na loss and increased K which diminishes blood volume and decreases blood pressure

Question 12

hypersecretion of cortisol?

Answer 12

Cushing’s syndrome

- tumour in adrenal cortex or pituitary giving off excess ACTH

Question 13

hypo-secretion of cortisol?

Answer 13

Addison’s disease

- hypo secretion of all adrenal steroid hormones due to autoimmune destruction of adrenal cortex

Question 14

symptoms in adrenal failure?

Answer 14

weakness, fatigue, weight loss, anorexia
skin pigmentation and vitiligo
salt cravings
unexplained vomiting and diarrhoea 
postural symptoms

Question 15

diagnosis of adrenal insufficiency ?

Answer 15

routine bloods
random cortisol
synacthen test

Question 16

treatment in adrenal insufficiency?

Answer 16

glucocorticoid replacement

• hydrocortisone, prednisolone, dexamethasone
• given to mimic diurnal variation

mineralocorticoid replacement

• fludrocortisone
• binds to aldosterone receptors

Question 17

what to do in illness?

Answer 17

double the hydrocortisone dosage

Question 18

hyper secretion in cortex?

Answer 18

Cushing’s syndrome (aldosterone)

Conn’s syndrome (adenoma or bilateral hyperplasia)

Question 19

hyper secretion in the medulla?

Answer 19

phaeochromocytoma (catecholamines)

Question 20

Cushing’s syndrome symptoms?

Answer 20

weakness of skin, muscle and bone
hypertension and HF due to sodium retention
DM due to insulin antagonism

Question 21

ACTH dependence in Cushing’s syndrome?

Answer 21

ACTH-dependent = pituitary tumour
ACTH-independent = adrenal tumour

Question 22

what figures on a random cortisol?

Answer 22

> 550nmol/l is not addison’s

<500nmol/l question adrenal status