Electrolytes Exam 3

Question 1

What are the functions of electrolytes

Answer 1

Volume and osmotic regulation, maintain pH, regulation of heart muscles, redox reaction, cofactors in enzyme activation, blood coagulation

Question 2

Extracellular anions and cations

Answer 2

Na+ and Cl-

Question 3

Intracellular anions and cations

Answer 3

K+ and Po4-

Question 4

What electrolyte is a major osmotic substance in osmolality and is its regulator?

Answer 4

Na+ is responsible for almost half of osmotic strength.

Intake of water in relationship to plasma osmolality, and response to thirst.

Excretion of water in relationship to blood volume and osmolality (release of ADH)

Question 5

True or False: The main function of antidiuretic hormone is to increase the reabsorption of sodium and increase the secretion of potassium.

Answer 5

False, ADH wants to ensure the patient is properly hydrated, and reabsorption of sodium makes person dehydrated.

Question 6

1-2% increase of osmolality causes 4x increase increase of

Answer 6

ADH

Question 7

Excess intake of water

Answer 7

lowers plasma osmolality; ADH and thirst are suppressed hyposmolality

Question 8

Absence of ADH will

Answer 8

increase urine production

Question 9

In a water deficit

Answer 9

ADH and thirst is activated

Question 10

ADH is released from

Answer 10

Anterior Pituitary to increase water absorption

Question 11

Osmolality is defined as

Answer 11

total solute concentration per kg of water (w/w)

Question 12

which electrolytes are main contributors to osmolality?

Answer 12

sodium, chloride, bicarbonate

Question 13

Increase in osmolality

Answer 13

decreases freezing point temperature and vapor pressure in determining osmolality

Question 14

What are some osmotically active substances?

Answer 14

ethanol, methanol, ethylene glycol, isopropanol, lactate or B-hydroxybutyrate

Question 15

How much water is in the body and how is it distributed intracellularly and extracellulary?

Answer 15

Water is 40-75% of total body
67% is intracellular fluid
33% is extracellular fluid

Question 16

Active transport

Answer 16

Requires energy
Intracellular K+ and plasma Na+ require energy from the breakdown of ATP by ATPase-dependent ion pumps.

Question 17

Diffusion

Answer 17

Passive movement
Depends on size, charge of ion, and nature of membrane through which its passing

Question 18

Rate of diffusion may be altered by

Answer 18

Physiological and hormonal processes

Question 19

Kidneys conserve or excrete sodium depending on

Answer 19

aldosterone; including Sodium reabsorption and potassium excretion

Question 20

Hyponatremia can be caused by

Answer 20

Increased Na loss (hypoadrenalism)
water imbalance (excess water intake)
Increased water retention (dilutional)

Question 21

What happens if Hypernatremia is not corrected by oral or intravenous infusion of fluids?

Answer 21

Cerebral edema and death can be induced

Question 22

What are the causes of hypernatremia?

Answer 22

Excess water loss (diabetes insipidus)
Decreased water intake or retention
Increased Na intake or retention (hyperaldosteronism) (sodium bicarbonate excess)

Question 23

What is the most common test method used for electrolytes?

Answer 23

Ion Selective Electrode, transport of a specific ion from high concentration to a low concentration, through a selective binding within a membrane that creates a potential difference.

Question 24

Pseudohyponatremia

Answer 24

Can occur when Na+ is measured using indirect ISE methods only
Increase of plasma water displacement where ion levels are falsely decreased (sample is diluted)

Question 25

Falsely decreased ionic activity causes

Answer 25

Na+ within vitro hemolysis (Na+ released from RBCs)

Question 26

Proximal tubules

Answer 26

reabsorb nearly all the K+

Question 27

Aldosterone causes

Answer 27

additional K+ to be secreted in the urine in exchange of sodium in distal tubule and collecting ducts. No renal threshold

Question 28

K+ uptake from the extracellular fluid into the cells is important in

Answer 28

normalizing an acute rise in the plasma, K+ concentrations due to an increase intake

Question 29

NaK ATPase pump can be inhibited by

Answer 29

Hypoxia Hypomagnesemia Digoxin overdose

Question 30

Insulin promotes

Answer 30

acute entry of K ions into skeletal muscle and liver; by increasing NaK ATPase activity

Question 31

Catecholamines (epinephrine)

Answer 31

promote cellular entry of K+

Question 32

Propranolol

Answer 32

impairs cellular entry of K+

Question 33

Forearm exercise during venipuncture can cause

Answer 33

erroneously high plasma K+ concentration

Question 34

Hypokalemia can be a result of

Answer 34

GI loss Urinary loss (Cushings syndrome, hyperaldosternonism) Cellular shift (alkalosis- increased aldosterone) Insulin overdose

Question 35

When patients have an underlying disorder of renal insufficiency, diabetes mellitus, or metabolic acidosis they are most likely going to have

Answer 35

Hyperkalemia

Question 36

True or False? blood is drawn into a vacutainer tube and allowed to clot. If the serum is not separated from the cells, the serum potassium will tend to decrease and the serum sodium will tend to increase.

Answer 36

False; K will increase and Na will decrease

Question 37

How is chloride quantitated and what ions are used for it to bound to?

Answer 37

Amperometric- coulometric titration Silver ions are used for it to be bound to

Question 38

When maintaining electroneutrality, The amount of Na+ reabsorbed is

Answer 38

limited to the amount of Cl- present in the proximal tubules

Question 39

Bicarb which helps maintain balance of cell comes from

Answer 39

carbon dioxide that was generated by cell metabolism that forms carbonic acid and splits into H+ and bicarbonate

Question 40

Bicarbonate diffuses into the plasma while Cl- diffuses into

Answer 40

RBC to maintain balance of cell, creating inverse relationship.

Question 41

Sweat chloride can be clinically presented as

Answer 41

Chronic obstructive pulmonary disease Pancreatic insufficiency

Question 42

Swear chloride is caused by

Answer 42

a defect in the cystic fibrosis transmembrane conductance regulator protein (CTFR)- more than 1500 mutations identified

Question 43

CFTR usually regulates

Answer 43

electrolytes transport across epithelial membranes

Question 44

Pilocarpine

Answer 44

is a cholinergic drug used to induce sweat in the positive electrode in the Gibson Cooke Qpit method

Question 45

The negative electrode in the Gibson Cooke Qpit method has

Answer 45

NaCl

Question 46

What is the ratio of bicarbonate to dissolved CO2?

Answer 46

bicarbonate to co2 is 20:1

Question 47

What electrolyte is a major component in the buffering system in the blood?

Answer 47

Bicarbonate

Question 48

Increased bicabonate can be seen in

Answer 48

Metabolic Alkalosis

Question 49

Decreased bicarbonate can be seen in

Answer 49

renal failure and respiratory alkalosis

Question 50

Overall regulation of Magnesium is controlled largely by

Answer 50

Kidney

Question 51

The only acceptable coagulant for calcium is

Answer 51

Heparin

Question 52

Ionized calcium is proportional to

Answer 52

amplitude of heart contraction, decreased concentration impairs myocardial function

Question 53

Lactate is a by product of

Answer 53

Anaerobic metabolism

Question 54

Which electrolyte is useful for metabolic monitoring of critically ill patients?

Answer 54

Lactate

Question 55

Which of the following electrolytes would be increased in the serum if the sample was hemolyzed?

Answer 55

Potassium Bicarb Phosphate

Question 56

Anion gap is

Answer 56

the difference between unmeasured anions and cations