Adrenals

Question 1

What is the cortex to medulla ratio?

Answer 1

90%:`10%

Question 2

What are the parts of the cortex? What do they do?

Answer 2

• zona glomerulosa (secrete mineralocorticoids - aldosterone)
• zona fasciculus (glucocorticoids - cortisol)
• zona reticularis (androgens) (and glucocorticoids)

Question 3

What cells are contained in the medulla? What do they do?

Answer 3

Chromaffin cells - release catecholamines (adrenaline and noradrenaline)

Question 4

What are the differences in shape between the right and left adrenal glands?

Answer 4

Right - pyramidal

Left - crescentic

Question 5

How does blood supply get to the adrenal glands?

Answer 5

• subscapular plexus -> vessels -> fenestrated sinusoids

- most cells 1/2 away from vascular endothelial cell

Question 6

What initiates steroid production in the cortex?

Answer 6

Cholesterol uptake and conversion

Question 7

What does hyperaldosteronism cause?

Answer 7

Low potassium, high blood pressure and alkalosis, suppressed renin activity
(high aldosterone)
(Conn’s syndrome)

Question 8

How do you diagnosis hyperaldosteronism?

Answer 8

• aldosterone:renin ratio
• CT adrenal
• adrenal venous sampling

Question 9

What is the mineralocorticoid receptor?

Answer 9

• aldosterone binds to them
• expressed in the nucleus
• cortisol also binds but cortisone inactivates unless overwhelming conditions

Question 10

What are the functions of aldosterone?

Answer 10

• stimulates Na/K ATPase and increases expression
• inserts additional ENacs
• stimulates H+ ATPase channel
  (THEREFORE when excess loss of H+ = metabolic alkalosis and K+ loss balancing intake of Na+)

Question 11

What is Liddle’s syndrome?

Answer 11

Increased expression of ENac = hypertension, hypokalemia, metabolic alkalosis

Question 12

What are the function of glucocorticoids?

Answer 12

Deal with stress:
starvation -> breakdown fuels
infection -> immunosuppression
Hypotension -> increase BP

Question 13

What are the causes of Cushing’s?

Answer 13

• iatrogenic
• corticotroph adenoma of the pituitary!!!
• bilateral adrenal hyperplasia
• cortisol secreting adrenal adenoma

Question 14

How is Cushing’s diagnosed?

Answer 14

• dexamethasone suppression test overnight
• 24 hour urine free cortisol
• MRI pituitary
• CT adrenals

Question 15

How do you treat Cushing’s?

Answer 15

PITUITARY: transphenoidal surgery, external beam radiotherapy, stereotactic radiosurgery

ADRENAL: adrenalectomy, etomidate

Question 16

Symptoms of Addison’s disease?

Answer 16

fatigue, weakness, myalgia, anorexia, weight loss, hyperpigmentation

Question 17

Causes of primary adrenal failure?

Answer 17

Autoimmune

TB

Question 18

What is Addison’s disease?

Answer 18

when something stressful happens and cannot respond to it = low bp, sodium, potassium, glucose

Question 19

How do you diagnose Addison’s?

Answer 19

Low 9am cortisol

high ACTH

Question 20

How do you treat Addison’s?

Answer 20

• replace steroid with hydrocortisone and fludrocortisone (mineralocorticoid)
• IV fluid resuscitation
• IM hydrocortisone

Question 21

What is congenital adrenal hyperplasia?

Answer 21

Defect in conversion to aldosterone and cortisol and excess ACTH secreted as no negative feedback
- stimulate cholesterol uptake in adrenal gland which is converted to cortisol then into testosterone

Question 22

What kind of stress do stress hormones respond to?

Answer 22

Starvation
Infection
Severe volume loss