Biochemistry

Question 1

what controls sodium

Answer 1

mineralocorticoid activity

Question 2

what controls water

Answer 2

ADH

Question 3

how does mineralocorticoid control sodium

Answer 3

sodium retention in exchange for potassium and/or hydrogen ions

Question 4

what happens if there is too much mineralocorticoid activity

Answer 4

sodium retention

Question 5

what happens if there is too little mineralocorticoid activity

Answer 5

sodium loss

Question 6

rule with sodium + water

Answer 6

water follows sodium

Question 7

what happens to water if there is sodium loss

Answer 7

water is lost

Question 8

main mineralocorticoid that influences sodium

Answer 8

aldosterone

Question 9

what is released from the kidney when BP is low

Answer 9

renin

Question 10

what cells release renin

Answer 10

juxtaglomerular cells

Question 11

what cells sense sodium concentration

Answer 11

macula densa

Question 12

what does renin act on

Answer 12

angiotensinogen

Question 13

where is angiotensinogen released from

Answer 13

liver

Question 14

what converts angiotensinogen to angiotensin 1

Answer 14

renin

Question 15

what converts angiotensin 1 to angiotensin 2

Answer 15

ACE

Question 16

where is ACE released from

Answer 16

lungs

Question 17

what does angiotensin 2 act on

Answer 17

adrenals – aldosterone release

Question 18

effect of aldosterone on kidneys

Answer 18

sodium + water retention - increased BP

Question 19

effect of increased ADH

Answer 19

concentrated urine

- high osmolarity

Question 20

effect of decreased ADH

Answer 20

dilute urine

- low osmolarity

Question 21

how does ADH work

Answer 21

acts on renal tubules to cause water reabsorption

Question 22

what can cause decreased sodium

Answer 22

SIADH

Addisons disease

Question 23

what is SIADH

Answer 23

syndrome of inappropriate ADH release

- excessive ADH secretion causing water retention and decreased sodium by dilution

Question 24

causes of SIADH

Answer 24

pneumonia
lung cancer
drugs- carbamazepine/ SSRI's 
subarachnoid haemorrhage 
hypothyroid

Question 25

what is Addison's disease

Answer 25

autoimmune decreased production of cortisol + aldosterone

Question 26

symptoms of Addison's disease

Answer 26

BRONZE SKIN abdo pain weakness weight loss

Question 27

tx Addison's

Answer 27

hydrocortisone as cortisol replacement | fludrocortisone as aldosterone replacement

Question 28

blood results in Addison's

Answer 28

low sodium high potassium low cortisol

Question 29

what can cause increased sodium

Answer 29

diabetes insipidus - increased water loss | decreased water intake

Question 30

what non-osmotic stimuli can cause ADH release

Answer 30

hypovolaemia hypotension pain N+V

Question 31

how can you get rid of excess sodium

Answer 31

diuretics

Question 32

2 most important factors in determining potassium concentration

Answer 32

GFR | plasma potassium concentration

Question 33

ECG hyperkalaemia

Answer 33

tall tented T waves | wide QRS

Question 34

symptoms of hyperkalaemia

Answer 34

cardiac arrest muscle weakness parasthesia

Question 35

causes of decreased potassium excretion

Answer 35

renal failure -- decreased GFR | hypoaldosteronism -- loss of sodium, decreased GFR, retention of potassium + hydrogen

Question 36

when do you see hyperkalaemia caused by hypoaldosteronism

Answer 36

ACE/ARB use

Question 37

causes of potassium redistribution

Answer 37

rhabdomyolysis -- potassium released from damaged cells metabolic acidosis -- increased hydrogen ions so potassium ions increase as well insulin deficiency-- insulin stimulates uptake of potassium

Question 38

Tx of hyperkalaemia

Answer 38

calcium gluconate | insulin + glucose to redistribute potassium

Question 39

symptoms of hypercalcaemia

Answer 39

``` stones - kidney stones bones - fractures groans - constipation, abdo pain moans - fatigue, myalgia, proximal muscle weakness physic overtones - depression, confusion ```

Question 40

most common causes of hypercalcaemia

Answer 40

primary hyperparathyroidism | hypercalcaemia of malignancy

Question 41

difference between primary hyperparathyroidism and hypercalcaemia of malignancy

Answer 41

PTH is HIGH in primary

Question 42

tx hypercalcaemia

Answer 42

IV saline | biphosphonates

Question 43

familial hypocalciuric hypercalcaemia

Answer 43

high calcium -- sensed by parathyroids as normal, so PTH is normal low urinary calcium

Question 44

acute adrenal insufficiency crisis

Answer 44

hypotension N+V dehydration

Question 45

results of synatchen test in Addisons

Answer 45

ACTH is given and should stimulate cortisol production | - plasma cortisol will remain low in Addison's as no cortisol is produced

Question 46

test for pituitary causes of adrenal insufficiency

Answer 46

insulin stress test

Question 47

where is most of sodium reabsorbed

Answer 47

proximal convoluted tubule

Question 48

where is 100% of glucose + amino acids reabsorbed

Answer 48

proximal convoluted tubule

Question 49

what is the descending limb permeable to

Answer 49

water

Question 50

what is used to distinguish between nephrogenic and central diabetes insipidus

Answer 50

Desmopressin - will retain salt + water in central when desmopressin is given - no change in nephrogenic as kidneys are not sensing ADH