Disorders of fluid and electrolyte balance Flashcards
What are the normal values for intra and extracellular Na+ concentrations?
intracellular 12
extracellular 145
mmol/L
What are 3causes of hyponatraemia?
Water retention to defect in excretion: advanced renal failure, effective circulating volume depletion, hormonal changes.
Primary polydipsia
Reset osmostat
Symptoms of hyponatraemia?
H2O into cells = cerebral oedema, lightheadedness, nausea, vomiting, lethargy, seizures
how can psueodohyponatraemia be caused by hyperproteinuria or hyperlipidaemia?
artefactually low serum Na serum conc
Symptoms of hypernatreamia
water out of cells = lower brain volume, lethargy and seizures
main causes of hypernatraemia?
water loss and impaired thirst
Na+retention
If you take in a load of K+, where is it stored till it’s cleared by the kidneys?
into cells
Where does most K+ secretion take place?
principle cells of LDT and CD
where is most of the K+ located?
most ICF K+ is stored in muscle
What are the normal ranges of ICF and ECF K+?
ICF - 140-150
ECF - 3.5-5
what’s the importance of K+ distribution?
Hyperkalaemia problems?
Hypokalaemia problems?
affects membrane potential - transcellular shifts are more important.
hyperkalaemia - impaired cardiac conduction/muscle weakness
hypokalaemia - inc mem excitability in cardiac myocytes due to removal of normal inactivation of Na+ channel
if pH increases/decreases, how does Ko change with it?
aaa
what 2 HORMONES can increase Na+/K+ ATPase activity?
a
how does plasma K+ influence movement of K+?
a
How does exercise influence the distribution of K+?
a
