Fluid-electrolyte physio

Question 1

what is formula for fluid balance

Answer 1

input-output

Question 2

what is main predictor of water volume in ECF

Answer 2

Na, as water follows Na

Question 3

what happens when add isotonic solution to body

Answer 3

adds ECF volume and ICF stays the same

Question 4

4 consequences of dec. ECF vol

Answer 4

1. low plamsa vol
2. low blood volume
3. low CO
4. low BP

Question 5

major consequence to high ECF volume

Answer 5

pulmonary edema

Question 6

how does added isotonic solution dist in ECF

Answer 6

1:3 plasma to ISF

Question 7

how does ISF volume change when change plasma vol? (2)

Answer 7

via changes in both hydrostatic and plasma oncotic pressure

Question 8

what happens in hypoalbumenemia

Answer 8

ECF vol stays the same, but movement from plasma to ISF

Question 9

how does body sense Na and ECF balance

Answer 9

via changes in effective arterial volume

Question 10

what is effective arterial volume

Answer 10

volume of blood in arterial tress that is effectively perfusing tissues

Question 11

what are sensors of effective arterial volume

Answer 11

baroreceptors (sense stretch)

Question 12

where are baroreceptors located

Answer 12

1. central arteries
2. renal afferet art.
3. cardiac atria and vents

Question 13

4 possible responses to baroreceptors

Answer 13

1. SNS
2. RAAS system
3. ADH
4. atrial naturetic peptide - to lower

Question 14

3 main functions of angiotensin 2

Answer 14

1. art. contstriction
2. renal Na absorption, both direct and via adlosterone
3. increased thirst and ADH

Question 15

3 effects of Ang2 induced eff arteriole constriction

Answer 15

1. incr glom cap pressure
2. changes in peritubular cap. factors
3. net effect of wasted out, but Na kept in

Question 16

3 pathologies of chronic RAAS activity

Answer 16

1. atheriosclerois
2. cardiac remodelling
3. renal scarring post-injury

Question 17

what is typical Na intake in a day

Answer 17

150mmol

Question 18

what is neg Na balance

Answer 18

intake less than output

Question 19

5 places Na can be lost

Answer 19

1. skin - sweat and burn oozes
2. GI - diarrhea or vomiting
3. kidneys
4. 3rd space
5. bleeding

Question 20

3 causes of too much Na from kidneys

Answer 20

1. diuretics (that inhib Na absrob)
2. glucose diuresis - after diabted mellitus
3. renal tubular disease

Question 21

what are 3rd space losses

Answer 21

fluid that is not in intravasuclr or interstitum - major surg, crush injury

Question 22

2 renal responses to hypovolemia

Answer 22

1. hypotension and renal vasoconstrict. - lower GFR

2. incr. renal Na absorb (Ang, SNS)

Question 23

manifestations of Na loss

Answer 23

1. fatigue
2. hypotension - may only be postural
3. tachy
4. cold sweaty skin (SNS activ)
5. low urine
6. circ. shock

Question 24

treatment of volume depletion

Answer 24

1. treat underlying cause

2. give fluids - isotonic

Question 25

what is pos. Na balance

Answer 25

intake more than excrete

Question 26

what happens when increase Na intake

Answer 26

1. will increase Na in ECF (more volume) | 2. eventually get Na excretion to equal, but never lose the ECF vol

Question 27

how is high ECF vol sensed

Answer 27

baroreceptors

Question 28

3 ways body tries to fix ECF vol increase

Answer 28

1. lower Na reabsorb (Ang2, aldo, SNS) 2. release naturetic peptide 3. pressure naturesis

Question 29

2 potential problems with Na excretions

Answer 29

1. primary renal prob - failure, nephrotic synd | 2. failure in signalling - heart failure, cirrosis

Question 30

what happens in renal falure

Answer 30

low GFR - can't get out Na

Question 31

3 mechanisms in nephrotic syndrome

Answer 31

1. protenuria>hypoalbumenemia>edema 2. protenuria>activation of eNaC>more Na reabsorbtion 3. proteinuria>hypoalbumenemia>increase LDL production>hypercholesterolemia

Question 32

what is effect of heart failure

Answer 32

1. low CO | 2. leads to Na retention to react to low arterial volume, because volume is all in veins

Question 33

how does cirrosis affect Na balance

Answer 33

1. scar liver 2. portal hypertenion > blood pools in vessels 3. low effective art. volume

Question 34

how much edema is detectable

Answer 34

3L

Question 35

2 main effects of Na high

Answer 35

1. hypertension | 2. edema (esp. pulmonary)

Question 36

treatment of high Na balnce (3)

Answer 36

1. reduce intake 2. increase Na out 3. treat underlying issue

Question 37

site of action and mech of acetazolamide

Answer 37

site: PCT mech: carbonic anhydrase inhib

Question 38

site of action and mech of furosamide

Answer 38

site: ALOH mech: inhibs Nak2Cl

Question 39

site of action and mech of hydrochlorothiazide and metazone

Answer 39

site: DCT mech: inhib NaCl transporter

Question 40

site of action and mech of spironolactone

Answer 40

site: CCD mech: aldosterone antagonist

Question 41

site of action and mech of amiloride

Answer 41

site: CCD mech: Na channel blocker

Question 42

4 places drugs can work on the RAAS

Answer 42

1. renin inhibitor 2. ACE inhib 3. aldosterone antagonist 4. angiotensin receptor blocker

Question 43

4 clinical uses of RAAS antagonists

Answer 43

1. hypertension 2. CHfailure 3. renal disease 4. after MI