Fluid and electrolytes- sodium and water Flashcards Preview

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Flashcards in Fluid and electrolytes- sodium and water Deck (25):
1

is there a greater conc of K+ in ICF or ECF

ICF

2

is there a greater conc of Na+ in ICF or ECF

ECF

3

how can you check for ECF clinically

plasma- bp, HR, jvp. interstitial fluid- skin turgor, muscous membranes, oedema

4

how can you check for ICF clinically

neuro status- cerebral oedema or dehydration

5

what is osmolality

ionic concentration of a fluid mOsm/kg

6

what is osmolality important for

determining the vol of a fluid compartment

7

what is tonicity

decription of osmolality compared to another solution, dependent on osmotically active components that do not cross the cell membrane

8

how much of total body water is ICF and ECF

2/3 and 1/3

9

how much of ECF is plasma

1/4

10

where is ADH released from

post pituitary

11

where does the ADH originate from

hypothalamic, supraventricular and supra orbital nuclei

12

what triggers ADH release

plasma osmolality increasing (thirst reflex), low bp (baroreceptors)

13

what does ADH bind to and what is the sequence of events

vasopressin 2 receptors in collecting duct, opens aquaporin channels leads to reabsorption of water from the urine into the plasma

14

what is isotonic fluid

fluid with the same osmlolality as plasma

15

what happens in isotonic depletion

decrease in ECF but no change in osmolality so no fluid shift

16

what happens in sodium depletion

decrease Na+, affects ECF so osmolality is higher in ICF thus leading to fluid shift into the ICF

17

what triggers renin release

decrease BP or Na+

18

what are the actions of angiotensin 2

acts on adrenal cortex to secrete aldosterone, and release ADH

19

what does aldosterone act on

tubular- for the reabsorption of Na+ and water; and the excretion of K+

20

what is hypertonic (referring to plasma)

decrease in plasma Na+

21

what is hypotonic (referring to plasma)

increase in plasma Na+ - so losing more water than sodium

22

what happens in water excess

Na+ decreases

23

what happens in sodium excess

osmolality higher in ECF than ICF so water shifts from here to ECF. however if driven by low circulating blood volume or decrease in BP, ADH is released which may result in further water retention and hyponatraemia

24

what is most fluid loss in the body

hypotonic

25

what lab investigations can be done

plasma/serum sodium, osmolality, plasma glucose, serum urea and creatinine, urine osmolality and sodium, urine vol, serum cortisol, serum TFTs