fluid-electrolyte physio 2

Question 1

how is water balance sensed

Answer 1

osmoreceptor in hypothalomus

Question 2

how does osmoreceptor work

Answer 2

shrinks and grows in response to tonicity

Question 3

what are 2 ADH receptors

Answer 3

v1 - vasoconstriction

v2 - antidiuretic

Question 4

2 stim for ADH release

Answer 4

1. high ECF osmolatiry

2. low eff. art volume

Question 5

how does ADH work

Answer 5

insertion of aquaporin channel into CCD and MCD

Question 6

3 stims. for water intake

Answer 6

1. habitual, social
2. thirst via hypernatremia
3. thirst via hypovolemia

Question 7

2 response to low free water

Answer 7

1. thirst to incr. water intake

2. ADH up to hold onto water

Question 8

what is free water

Answer 8

water without Na

Question 9

how much free water in 1L of [70] Na

Answer 9

0.5L free water and 0.5L [140]

Question 10

2 potential causes of hypernatremia

Answer 10

1. too much Na in ECF - drank saltwater

2. too little water in ECF - reduced intake or high loss

Question 11

what is diabetes insipidus

Answer 11

lack of and ADH effect

Question 12

2 types of diabetes insipidus

Answer 12

1. central - pit/hypo impaired release

2. nephrogenic - kidney doesn’t repsond

Question 13

what is acute and adaptive cell change to hypernatremia

Answer 13

acute: cells shrink and pull away

adaptive; brain imports new K particles to adapt

Question 14

how to treat hypernatremia

Answer 14

1. treat cause

2. give free water

Question 15

how to give free water

Answer 15

by mouth if can

Question 16

how to give IV free water

Answer 16

1. D5W

2. 50 normal saline

Question 17

what is ECF vol in hyponatremia

Answer 17

could be high low or normal

Question 18

what is expected response to hyponat.

Answer 18

osmoreceptor drops ADH - excrete free water

Question 19

4 possible causes of hyponat.

Answer 19

1. ADH present when it should be supressed
2. vast intake
3. advanced renal failure
4. reduced delvery of filtrate to ALOH

Question 20

2 possible reasons for ADH to be present despite hyponatremia

Answer 20

1. effective art, volume depletion - baroreceptor action via hypovolemia
2. non-volume stim for ADH - disease or drug

Question 21

what is acute and adaptive cell change to hyponatremia

Answer 21

acute: cells swell and give cerebral edema
adaptive: cells export particles and return to nromals