electrolyted

Question 1

What is the tubular control of Na?

Answer 1

Aldosteron: DCT and CD leads to increased Na reabsorption from the filtrate
Natriuretic peptides: reduce Na reabsorption and inhibit renin
High GFR: decreased Na reabsorption

Question 2

How is K+ controlled?

Answer 2

Insulin and catecholamines: ↑Na/K ATPase stimulation K+ uptake into the cells
H+ levels: H+ and K+ compete for exchange across the cell so raise in one will lead to drop in the other

Question 3

Which compounds are predominantly invloved in control of osmolarity? what is the normal blood osmolarity

Answer 3

2* K and Na and urea and glucose (280-300 mmol/L)

Question 4

What determines the renal water reabsorption

Answer 4

Water follows Na hence reabsorption increased with raised osmolarity which also stimulates thirs and ADH secretion

Question 5

Define GFR

Answer 5

volume of fluid filtered by the glomeruli per minute (units mL/min)

Question 6

what are the causes of metabolic acidosis and ↑ anion gap

Answer 6

• Lactic acid (shock, infection, tissue ischaemia)
• Urate (renal failure)
• Ketones (diabetes mellitus, alcohol)
• Drugs/toxins (salicylates, biguanides, ethylene glycol, methanol)

Question 7

what are the causes of metabolic acidosis that do not alter anion gap

Answer 7

loss of bicarbonate or ingestion of hydrogen i.e. Renal tubular acidosis

Diarrhoea
Drugs (acetazolamide)
Addison’s disease
Pancreatic fistula
Ammonium chloride ingestion

Question 8

what are the causes of metabloic alkylosis

Answer 8

Vomiting
K+ depletion (diuretics)
Burns
Ingestion of base

Question 9

what factors control renin

Answer 9

pressure changes in affarent arterioles, sympathetic tone, chloride and osmotic concentration via DCT and Macula densa, local prostaglandins and nitric oxide

Question 10

Name all the effects of angiotensin 2?

Answer 10

Vasoconstriction, increased sympathetic tone, increased release of ADH, increased aldosteron secretion

Question 11

where in the kidney is vit D synthesised

Answer 11

CD and DCT

Question 12

what is a normal range for calcium and what proportion is albumin bound?

Answer 12

2.25-2.5 mmol/L 40% bound

Question 13

what are the causes of hypercalcaemia

Answer 13

dehydration, malignancy, primary hyperparathyrodisem (tertiary rare), sarcoidosis • Vit D intoxication, thyrotoxicity, lithium, thiazides