Sodium

Question 1

major cation outside the cell

Answer 1

sodium

Question 2

most abundant cation in ECF (regardless of being intravascular or interstitial)

Answer 2

sodium

Question 3

principal osmotic particle outside the cell

Answer 3

sodium

Question 4

reference range of sodium in serum

Answer 4

135 - 145 mmol/L

Question 5

reference range of sodium in CSF

Answer 5

136 - 150 mmol/L

Question 6

reference range of sodium in urine

Answer 6

40 - 220 mmol/day

Question 7

condition where the threshold critical value of Na is 160 mmol/L or more

Answer 7

hypernatremia

Question 8

condition where the threshold critical value of Na is 120 mmol/L or less

Answer 8

hyponatremia

Question 9

Na stands for

Answer 9

natrium

Question 10

concentration of substance in the blood wherein it stops reabsorption by the kidneys

Answer 10

renal threshold

Question 11

renal threshold of Na

Answer 11

110 - 130 mmol/L

Question 12

2 factors that maintains sodium conc. in serum/plasma

Answer 12

1. water intake (increased water, decreased Na [diluted by water])
2. water excretion (more water excreted increases Na conc.)

Question 13

ATP driven that promotes exit of 3 sodium outside the cell in return with 2 potassium

Prevents osmotic rupture of cells

Answer 13

Sodium-Potassium-ATPase ion pump

Question 14

how does Sodium-Potassium-ATPase ion pump prevents osmotic cell rupture?

Answer 14

excretion of 3 sodium also secretes 3 water molecules

(decreases water content inside the cell, thus, no rupture)

Question 15

2 Functions of Sodium-Potassium-ATPase ion pump

Answer 15

maintains increased concentration of intracellular POTASSIUM

maintains increased concentration of extracellular SODIUM

Question 16

defense to hyperosmolality and hypernatremia

Answer 16

thirst

Question 17

increased water excretion leads to increased or decreased sodium?

Answer 17

increased

Question 18

blood volume status is affected by Na excretion through:

Answer 18

aldosterone
angiotensin II
ANP

Question 19

• blocks aldosterone and renin secretion
• inhibits action of angiotensin II and vasopressin

Answer 19

Atrial Natriuretic Peptide

Question 20

60-75% of filtered sodium are reabsorbed by

Answer 20

PCT

Question 21

how is sodium regulated in kidneys? (2)

Answer 21

filtered Na are reabsorbed by PCT
reabsorption of Na in DCT by aldosterone

Question 22

decreased plasma Na concentration and its value

Answer 22

Hyponatremia (<135 mmol/L)

Question 23

most common electrolyte disorder

Answer 23

Hyponatremia

Question 24

value where hyponatremia symptoms starts

Answer 24

125-130 mmol/L

Question 25

value of sodium that results to severe neuropsychiatric symptoms or momentary memory loss

Answer 25

<125 mmol/L

Question 26

glucose condition that causes hyponatremia

Answer 26

hyperglycemia (DM also causes electrolyte imbalance wherein water released in ECF dilutes Na)

Question 27

urine sodium of 20 mmol/day indicates what condition

Answer 27

renal sodium and water loss

Question 28

100 mg/dL INCREASE in glucose is equivalent to?

Answer 28

1.6 mmol/L DECREASE in sodium (water is released every glucose uptake by the cell (by insulin), which dilutes Na (hyponatremia)

Question 29

4 general causes of hyponatremia

Answer 29

• increased sodium loss • increased water retention • water imbalance • pseudohyponatremia

Question 30

explain the mechanism of hypoadrenalism in increasing sodium loss

Answer 30

↓ aldosterone production —> no sodium is reabsorbed in DCT —> sodium is loss in urine

Question 31

mechanism of potassium deficiency (hypokalemia) in increasing sodium loss

Answer 31

decreased potassium —> promotes potassium retention in KIDNEYS —> sodium excretion (↓ Na) *retained K = excretes Na*

Question 32

mechanism of diuretics (thiazides) in increasing sodium loss

Answer 32

promotes urine flow (by inhibiting renal Na reabsorption in DCT)

Question 33

mechanism of ketonuria in increasing sodium loss

Answer 33

ketones are loss along with Na in urine ketone loss = Na loss

Question 34

why does ↑ water retention causes hyponatremia

Answer 34

dilutes Na

Question 35

conditions that promotes ↑ water retention leading to hyponatremia

Answer 35

• renal failure • nephrotic syndrome • hepatic cirrhosis • CHF

Question 36

conditions that promotes water imbalance leading to hyponatremia

Answer 36

• polydipsia (excessive thirst) - dilutes plasma and electrolytes (Na) • SIADH - ↑ADH; ↓urine output; ↑blood volume; dilutes Na

Question 37

Sodium measurement method that leads to pseudohyponatremia (systematic error)

Answer 37

INDIRECT Ion Selective Electrode (dilution requiring) if patient has: • hyperlipidemia • hyperproteinemia *lipids and proteins displaces Na during measurement—> false ↓*

Question 38

↑ plasma Na conc. and its value

Answer 38

hypernatremia (>145 mmol/L)

Question 39

True or False: Water deficit (↓ blood vol) of 1-2% causes thirst which affects plasma concentration

Answer 39

TRUE

Question 40

indicative of hypothalamic dse due to nonresponsive hypothalamus that can no longer promote THIRST and increases vasopressin

Answer 40

chronic hypernatremia

Question 41

moderate water deficit value

Answer 41

150-160 mEq/L or mmol/L sodium

Question 42

severe water deficit value

Answer 42

>165 mEq/L or mmol/L sodium

Question 43

most common cause of hypernatremia

Answer 43

excess water loss

Question 44

mechanism of diabetes insipidus in causing increased sodium

Answer 44

EXCESS WATER LOSS: polyuria —> vasopressin deficiency —> increase urination —> ↑ Na conc.

Question 45

mechanism of renal tubular disorder in causing increased sodium

Answer 45

EXCESS WATER LOSS: impairment to concentrate urine (in same conc.) SG must be 1.010

Question 46

profuse sweating and hyperventilation causes how many loss of water per day

Answer 46

1 liter

Question 47

decreased water intake in population of old people, infants, and mental impairment causes hypernatremia or hyponatremia?

Answer 47

hypernatremia

Question 48

conditions that has an ↑ sodium intake or retention

Answer 48

• hyperaldosteronism (Conn’s dse) • sodium bicarbonate infusion • ↑ NaCl administration • Sea water ingestion

Question 49

drinking sea water leads to?

Answer 49

hypernatremia and excessive thirst

Question 50

accepted specimen for Na analysis

Answer 50

1. serum 2. plasma 3. 24 hr urine 4. sweat 5. whole blood

Question 51

additives used if plasma specimen is utilized for Na analysis

Answer 51

lithium heparin lithium oxalates ammonium heparin

Question 52

variable that causes false ↓ Na

Answer 52

MARKED hemolysis due to dilutional effect

Question 53

5 Methods used for Na analysis

Answer 53

1. Gibson and Cooke Pilocarpine Iontophoresis 2. Ion Selective/Specific Electrode 3. AAS 4. Emission Flame Photometry 5. Albanese Lein (chemical method)

Question 54

method of sweat sample collection

Answer 54

Gibson and Cooke Pilocarpine Iontophoresis

Question 55

sweat inducers used in Gibson and Cooke Pilocarpine Iontophoresis

Answer 55

Pilocarpine Mild current (iontophoresis)

Question 56

output required in Gibson and Cooke Pilocarpine Iontophoresis

Answer 56

>50 mg sweat within 30 mins

Question 57

what must be done to the sweat sample after collection?

Answer 57

tightly sealed (volatile/easily evaporates)

Question 58

Na membrane responsible for selectivity of ISE

Answer 58

Glass Aluminum Silicate

Question 59

measurement of non-excitable ion and excitable ion, respectively

Answer 59

AAS EFP

Question 60

reagents used in Albanese Lein

Answer 60

Cupric sulfate NaOh