The adrenal gland

Question 1

Vasculature of adrenal glands, veins and arteries

Answer 1

Right adrenal gland drains into IVC. Left drains into renal vein. Both have many arteries but only one vein.

Question 2

Adrenal medulla

Answer 2

Chromaffin cells secrete catecholamines - eg adrenaline, epinenphrine

Question 3

Adrenal cortex

Answer 3

Secretes corticostreroids - eg aldosterone, cortisol , little bit of sex steroids

Question 4

Layers of adrenal cortex outer to inner

Answer 4

Zona glomerulosa
Zona fasciculata
Zona reticularis

Question 5

what are steroids

Answer 5

molecules coming from cholesterol

Question 6

Aldosterone pathway

Answer 6

Cholesterol -
(3hydroxysteroid dehydrogenase) progesterone - (21hydroxylase) 11-deoxycorticosterone - (11) corticosterone - (18) aldosterone

Question 7

Cortisol pathway

Answer 7

Cholesterol - (3hydroxysteroid dehydrodgenase) progesterone - (17hydroxylase) 17 - OH progesterone - (21) 11-deoxycortisol - (11) cortisol

Question 8

Aldosterone method of action

Answer 8

To maintain blood pressure
Stiumlates Na+ reabsorption in distal convoluted tubule and cortical collecting duct in kidney (and sweat glands, gastric glands, colon)
Stimulates K+ and H+ secretion in distal convoluted tubule and cortical collecting duct.

Question 9

Regulation of aldesterone

Answer 9

Juxtaglomerular apparatus detects low blood pressure, make renin (usually inhibited by high BP).
Renin converts angiotensinogen to angiotensin 1 converted by angiotensin converting enzyme ACE to angiotensin 2
Causes vasoconstriction but most importantly stimulates aldesterone production from Zona glomerulosa of adrenal cortex.

Question 10

Physiological effects of cortisol

Answer 10

peripheral protein catabolism
hepatic gluconeogenesis
increased blood glucose concentration
fat metabolism
enhanced effect of glucagon and catecholamines
increase BP

Question 11

Addisons’s disease - Primary adrenal failure. Summary is

Answer 11

Autoimmune destruction of adrenal cortex. Tuberculosis organisms eats it.
Cortisol and aldesterone deficiency, salt loss, low BP eventual death

Question 12

Addison’s disease symptoms

Answer 12

Darkening of skin - hyperpigmentation
Severe fatigue
Unintentional weight loss
Low BP
Vomiting
Diarrhoea

Question 13

Why do addison’s patients have hyperpigmentation?

Answer 13

POMC, pro-opio-melanocortin is a large precursor protein which is cleaved to form ACTH and MSH and endorphins.
Adrenal failure, no cortisol leads to no inhibition of ACTH production, more produced, more MSH as a byproduct.

Question 14

Treatment of Addison’s disease

Answer 14

Rehydrate with normal saline

Dextrose to prevent hypoglycemia

Question 15

Cushing’s syndrome symptoms

Answer 15

Lose protein in muscles, weak - myopathy
thin skin
centripetal obesity 
Mental changes - depression
High blood pressure
Diabetes
Osteoporosis
Stretch marks.

Question 16

Cushing’s syndrome causes

Answer 16

too much cortisol
Taking steroids orally
pituitary dependent cuhsing's disease
ectopic ACTH (lung cancer)
adrenal adenoma or carcinoma

Question 17

Precursor for Adrenaline and Noradrenaline synthesis

Answer 17

Tyrosine

Question 18

Storage of catecholamines, binding of Adrenaline and Noradrenaline in blood

Answer 18

stored in cytoplasmic granules and released in response to ACh from preganglionic sympathetic neurones. Adrenaline and Noradrenaline bind to albumin

Question 19

Degradation of adrenaline and noradrenaline

Answer 19

monoamine oxidase and catechol-O-methyl transferase

Question 20

Static blood tests

Answer 20

test in morning - many hormones secreted according to circadian rhythm
only a snapshot hormone release is pulsatile, may have just missed a pulse.

Question 21

Dynamic blood tests

Answer 21

suppression test - too much hormone

stimulation test - too little hormone

Question 22

Troubleshooting test results

Answer 22

Have conditions changed?
Look at pre-test probability
Logistics of test - wrong patient?
Repeat test