sodium and water balance

Question 1

what controls water balance

Answer 1

ADH
-causes water to be reabsorbed form the renal tubules

-increase ADH in small volumes of conc. urine
-decrease ADH in large “

makes the renal tubules permeable to water

Question 2

what is urine osmolality

Answer 2

concentration/dilution of urine

Question 3

SIADH

Question 4

what are the 2 kinds of stimuli for ADH release

Answer 4

osmotic = serum osmolality in healthy people
non-osmotic = hypotension, hypovolaemia, pain, nausea, vomitting

Question 5

what controls sodium balance

Answer 5

steroids - mineralocorticoid activity

refers to Na absorption in exchange for K or H

-too much mineralocorticoid activity means Na gain and too little means Na loss

Question 6

mineralocorticoids

Answer 6

aldosterone
other ie cortisol

Question 7

T/F Na loss or gain is solely from/to the ECF

Answer 7

T

this is clinically relevant as water follows Na ie loss of Na from ECF = loss of water from ECF

Question 8

hyponatraemia clinical signs

Answer 8

dry mouth, increased pulse, a postural decrease in BP, soft/sunken eyes, decreased skin turgor, decreased consciousness, decreased urine output

Question 9

hypernatraemia clinical signs

Answer 9

coughing
tiredness
SOB
pleural effusion
oedema
pulmonary oedema
ascites

Question 10

causes of hyponatraemia

Answer 10

adrenal/kidney
gut
skin
compulsive water secretion
H2O excretion eg SIADH

Question 11

causes of hypernatreamia

Answer 11

some IV meds
near-drowning
malicious
H2O loss eg DM
H2O intake eg very young or old