THERMOREGULATION AND ELECTROLYTE BALANCE Practise questions

Question 1

Define SIADH

Answer 1

Syndrome of inappropriate anti-diuretic hormone secretion

Question 2

Describe what changes to extracellular fluid (ECF) concentration and volume during exercise induced dehydration (e.g., sweating)?

Answer 2

Increase in osmolality (e.g., concentration) in ECF

Limited change in volume as fluid moves from the ICF to ECF.

Question 3

What are normal (i.e. physiologically appropriate) sodium and potassium concentrations in intracellular (ICF) and extracellular fluid (ECF)?

Answer 3

ECF sodium = 135 – 145 mmol/L

ECF potassium = ~4.5 – 5.5 mmol/L

ICF sodium = ~5 mmol/L

ICF potassium = ~150 – 170 mmol/L

Question 4

Does a higher sweat loss rate increase or decrease sweat sodium concentration, and why?

Answer 4

Increase

Sodium reabsorbed in sweat gland duct

Higher sweat loss rate, less transit time for sodium reabsorption