Y2 IMBALANCES OF ELECTROLYTES, METABOLITES, HORMONES ETC. Flashcards
Symptoms of hyponatraemia.
- altered conscious.
- confusion
- nausea
- vomiting
- fitting
same as hypernatraemia
symptomatic hyponatraemia is?
life-threatening
loss/gain of Na+ is from the?
ECF only
Na+ is confined to the?
ECF
if ECF volume is too high?
kidneys excrete Na+ which is followed by water.
if ECF volume is too low?
kidneys retain Na+ to retain water
by what two mechanisms does hyponatraemia develop?
- reduced sodium
- increased water
how do you treat hyponatraemia?
- if due to too little sodium, give the patient sodium.
- if due to too much water, restrict fluids.
sodium is controlled by?
mineralocorticoid activity
how does mineralocorticoid control sodium?
sodium is retained in exchange for potassium +/or hydrogen ions.
which steroids have mineralocorticoid activity?
- aldosterone.
- cortisol.
excess mineralocorticoid activity causes?
sodium retention
+ thus water retention
little mineralocorticoid activity causes?
sodium loss
+ thus water loss
ADH is released?
by the posterior pituitary in response to stimuli.
ADH acts on the?
renal tubules
ADH acts on the renal tubules to cause?
water reabsorption - i.e. anti-diuresis.
increased ADH causes?
concentrated urine i.e. water retention
reduced ADH causes?
dilute urine i.e. water loss
the concentration of urine is assessed as?
urine osmolality
concentrated urine can be described in terms of osmolality as?
high osmolality
dilute urine can be described in terms of osmolality as?
low osmolality
another name for ADH?
arginine vasopressin
how does ADH cause water reabsorption?
countercurrent multiplication
in SIADH what is meant by inappropiate?
inappropiate with regards to the osmolal state