Na+ and water balance

Question 1

the fact that the ___ has double the volume of the ___ means that the clinical signs of dehydration are muted

Answer 1

ICF>ECF

28L:14L

Question 2

concn of Na and K+ in ICF and ECF

Answer 2

Na+ = 4mmol/l ICF : 140mmol/l ECF

K+ is the reciprocal

Question 3

body uses ___ to regulate ECF volume

Answer 3

Na+ concn

Question 4

if pathology causes Na+ excretion to increasse => ___ Na+ loss exclusively => ___ signs of dehydration that develop ___

Answer 4

ECF
obvious
quickly

Question 5

Na+ is controlled by _____ activity

= causes Na+ retention in exchange for __+__

Answer 5

mineralocorticoid

K+ and H+

Question 6

if mineralocorticoid activity is too low then __ is lost => __ lost

Answer 6

Na+

H2O

Question 7

ADH acts on the __ causing ____

if it has a high level => ___ urine with ___ osmolarity

Answer 7

renal tubules
H2O retention
concentrated urine
high osmolarity

Question 8

countercurrent multiplication occurs in the ___ and leads to the production of ___ urine

Answer 8

loop of Henle

hypoosmotic urine

Question 9

Na+ and water balance:
in thick ascending limb in loop of Henle process =
it is ___ to water

Answer 9

active reabsorption of NaCl to the renal medulla

impermeable

Question 10

Na+ and water balance:

in descending limb of loop of Henle process =

Answer 10

water moves into the medulla

Question 11

Na+ and water balance:

in thin ascending limb of loop of Henle process =

Answer 11

passive diffusion NaCl to the medulla

Question 12

the most common cause of a low Na+ concn = low level of ___ this can be caused by __/___

Answer 12

H2O

not drinking enough/ diabetes insipidus

Question 13

In Addision’s ____ activity is reduced

this causes Na+ to ___ and K+ ___

Answer 13

mineralocorticoid
Na+ low levels
K+ retention

Question 14

SIADH causes __ to increase and although dont have symptoms of it the basic biochem shows ___

Answer 14

H2O increase

hyponatraemia (because of increased H2O)

Question 15

an exogenous ADH that can be used in DI

Answer 15

desmopressin

Question 16

oedema - effectively ____ which causes ADH and aldosterone to compensate so makes it ___

Answer 16

circulatory volume depletion

worse

Question 17

hypo/hypernatraemia is it serious ? YES if < __mmol/l or >___mmol/l

Answer 17

<120

>155

Question 18

factors that make hypo/hypernatraemia serious (3)

Answer 18

symptoms
fallen/risen sharply
v low (<120mmol/l) or v high (>155)

Question 19

if hypernatraemic due to too much Na+ Rx =

Answer 19

diuretics and replace water

Question 20

pseudohyponatraemia is due to ___

Answer 20

hyperlipidaemia