adrenal gland

Question 1

where are the adrenal glands located

Answer 1

above the kidneys

Question 2

where does the left adrenal vein drain into

Answer 2

the renal vein

Question 3

where does the right adrenal vein drain into

Answer 3

the inferior vena cava (IVC)

Question 4

how many veins and arteries do the adrenals have

Answer 4

many arteries but only 1 vein

Question 5

microanatomy of the adrenal glands

Answer 5

adrenal cortex which has 3 layers - zona glomerulosa/fasciculata/reticularis
adrenal medulla

Question 6

what does the adrenal cortex secrete

Answer 6

corticosteroids

Question 7

what does the adrenal medulla secrete

Answer 7

catecholamines

Question 8

what does the adrenal medulla do

Answer 8

secretes catecholamines by neuroendocrine/chromaffin cells
adrenaline/epinephrine 80%
noradrenaline/norepinephrine 20%
dopamine

Question 9

what does the adrenal cortex do

Answer 9

secretes corticosteroids
mineralocorticoids (aldosterone)
glucocorticoids (cortisol)
sex steroids (androgens, oestrogens)

Question 10

what zona secretes aldosterone

Answer 10

zona glomerulosa

Question 11

what zona secretes cortisol (androgens and oestrogens)

Answer 11

zona fasciculata and reticularis

Question 12

where do steroid hormones come from

Answer 12

cholesterol

Question 13

what is the precursor for adrenal gland secretions

Answer 13

cholesterol

Question 14

how many carbons does cholesterol have

Answer 14

27

Question 15

what is an enzyme

Answer 15

a protein that catalyses a specific reaction
various enzymes are present in cells
specific enzymes catalyse the synthesis of particular alterations to the molecule

Question 16

what is the pathway to get from cholesterol to aldosterone

Answer 16

cholesterol undergoes side chain cleavage > pregnenolone
pregnenolone is oxidised by 3 beta hydroxysteroid dehydrogenase > progesterone
progesterone is oxidised 3 times by 21, 11, 18 hydroxylases > aldosterone

Question 17

what is the pathway to get from cholesterol to cortisol

Answer 17

cholesterol undergoes side chain cleavage > pregnenolone
pregnenolone is oxidation by 3 beta hydroxysteroid dehydrogenase > progesterone
progesterone is oxidised by 17, 21, 11 hydroxylases to form cortisol

Question 18

what does aldosterone do

Answer 18

controls blood pressure
conserves Na by stimulating its reabsorption
stimulates K+ and H+ secretion

Question 19

where does aldosterone stimulate Na reabsorption and K+/H+ secretion

Answer 19

in distal convoluted tubule and cortical collecting duct in the kidney
and in sweat glands, gastric glands and colon - Na reabsorption

Question 20

how is aldosterone regulated (4)

Answer 20

• by renin release when blood pressure falls (stimulates other cells)
• increased renal sympathetic activity (directed to JGA cells) juxtaglomerular apparatus
• decreased Na+ load to the top of loop of Henle (macula densa cells)
• noradrenaline

Question 21

what is associated with decreased arterial blood pressure

Answer 21

decreased renal perfusion pressure

Question 22

what does renin do

Answer 22

stimulates conversion of angiotensinogen to angiotensin 1

Question 23

what converts angiotensin 1 to 2

Answer 23

ACE

Question 24

what does angiotensin 2 do

Answer 24

regulator of aldosterone release
binds to receptors in zona glomerulosa
causes vasoconstriction (increased BP)

Question 25

what does aldosterone do

Answer 25

increases blood volume > increases BP

Question 26

what are the effects of angiotensin 2 on the adrenals

Answer 26

``` activation of the following enzymes side chain cleavage 3 hydoxysteroid dehydrogenase 21 hydroxylase 11 hydroxylase 18 hydroxylase ```

Question 27

summary of action of aldosterone

Answer 27

cholesterol > aldosterone > controls BP, increases sodium and lowers potassium

Question 28

when is cortisol released

Answer 28

normal stress response

Question 29

what are metabolic effects of cortisol

Answer 29

peripheral protein catabolism (break down for energy) hepatic gluconeogenesis increased blood glucose concentration fat metabolism (lipolysis in adipose tissue) enhanced effects of glucagon and catecholamines

Question 30

other effects of cortisol

Answer 30

weak mineralocorticoid effects | renal and cardiovascular effects - excretion of water load, increased vascular permeability

Question 31

how is cortisol secretion regulated - ACTH

Answer 31

negative feedback at 2 levels

Question 32

effects of ACTH on the adrenal glands

Answer 32

``` activation of these enzymes side chain cleavage 3 beta hydroxysteroid dehydrogenase 17 hydroxylases 21 hydroxylases 11 hydroxylases ```

Question 33

what rhythm does cortisol have

Answer 33

diurnal and circadian

Question 34

what is addisons disease

Answer 34

primary adrenal failure an autoimmune disease where the immune system decides to destroy the adrenal cortex tuberculosis of the adrenal glands the pituitary starts secreting lots of ACTH and hence MSH (melanocyte stimulating hormone?) > increased pigmentation > autoimmune vitiligo may coexist no cortisol or aldosterone > low blood pressure cortisol and aldosterone deficiency salt loss low BP eventual death

Question 35

symptoms and signs of addisons

Answer 35

``` hyperpigmentation low bp weakness weight loss gastrointestinal (nausea, diarrhoea, vomiting, constipation, abdominal pain) vitiligo ```

Question 36

what does an addisonian/adrenal crisis consist of

Answer 36

``` fever syncope (fainting) convulsions hypoglycaemia hyponatremia - low sodium severe vomiting and diarrhoea ```

Question 37

what is POMC

Answer 37

pre-opio melanocortin a large precurosor protein that is cleaved to form a number of smaller peptides - ACTH, MSH and endorphins so people with pathologically high ACTH may become tanned

Question 38

urgent treatment of addisonian crisis

Answer 38

rehydrate with normal saline give dextrose (glucose) to prevent hypoglycaemia which could be due to glucocorticoid deficiency give hydrocortisone or another glucocorticoid

Question 39

what is Cushings syndrome

Answer 39

too much cortisol due to adrenal tumour or tumour of pituitary (more ACTH) cortisol inhibits protein synthesis excess cortisol or other glucocorticoid

Question 40

causes of Cushings syndrome

Answer 40

taking steroids by mouth (common) - asthmatics pituitary dependent cushings disease (pituitary adenoma) ectopic ACTH (lung cancer) - wrong place adrenal adenoma or carcinoma (tumour)

Question 41

symptoms and signs of Cushings

Answer 41

``` moon face red cheeks fat pads - buffalo hump mental changes eg depression thin skin easy bruising impaired glucose tolerance (diabetes) high blood pressure proximal myopathy (muscle weakness) thin arms and legs red striae pendulous abdomen poor wound healing ```

Question 42

what is the role of catecholamines

Answer 42

fight or flight response | tachycardia, sweating, increased blood glucose, alertness, vasoconstriction

Question 43

how does NA and A circulate in the blood and what is it degraded by

Answer 43

bound to albumin | degraded by 2 hepatic enzymes - monoamine oxidase and catechol-O-methyl transferase

Question 44

where is the adrenal medulla derived from

Answer 44

ectodermal neural crest

Question 45

what is the precursor for NA and Adr synthesis

Answer 45

tyrosine

Question 46

where are catecholamines stored

Answer 46

in cytoplasmic granules and released in response to ACh from preganglionic sympathetic neurones

Question 47

how is dopamine made

Answer 47

tyrosine is oxidised to dopa | dopa is oxidised to dopamine

Question 48

how is dopamine made

Answer 48

tyrosine is oxidised to dopa | dopa is oxidised to dopamine

Question 49

where does adrenaline come from

Answer 49

dopamine | by oxidation and then methyl addition to become epinephrine