Electrolytes Exam 3 Flashcards

1
Q

What are the functions of electrolytes

A

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

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2
Q

Extracellular anions and cations

A

Na+ and Cl-

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3
Q

Intracellular anions and cations

A

K+ and Po4-

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4
Q

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

A

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)

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5
Q

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

A

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

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6
Q

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

A

ADH

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7
Q

Excess intake of water

A

lowers plasma osmolality; ADH and thirst are suppressed hyposmolality

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8
Q

Absence of ADH will

A

increase urine production

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9
Q

In a water deficit

A

ADH and thirst is activated

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10
Q

ADH is released from

A

Anterior Pituitary to increase water absorption

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11
Q

Osmolality is defined as

A

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

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12
Q

which electrolytes are main contributors to osmolality?

A

sodium, chloride, bicarbonate

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13
Q

Increase in osmolality

A

decreases freezing point temperature and vapor pressure in determining osmolality

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14
Q

What are some osmotically active substances?

A

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

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15
Q

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

A

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

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16
Q

Active transport

A

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

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17
Q

Diffusion

A

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

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18
Q

Rate of diffusion may be altered by

A

Physiological and hormonal processes

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19
Q

Kidneys conserve or excrete sodium depending on

A

aldosterone; including Sodium reabsorption and potassium excretion

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20
Q

Hyponatremia can be caused by

A

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

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21
Q

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

A

Cerebral edema and death can be induced

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22
Q

What are the causes of hypernatremia?

A

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

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23
Q

What is the most common test method used for electrolytes?

A

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.

24
Q

Pseudohyponatremia

A

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)

25
Q

Falsely decreased ionic activity causes

A

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

26
Q

Proximal tubules

A

reabsorb nearly all the K+

27
Q

Aldosterone causes

A

additional K+ to be secreted in the urine in exchange of sodium in distal tubule and collecting ducts.

No renal threshold

28
Q

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

A

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

29
Q

NaK ATPase pump can be inhibited by

A

Hypoxia
Hypomagnesemia
Digoxin overdose

30
Q

Insulin promotes

A

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

31
Q

Catecholamines (epinephrine)

A

promote cellular entry of K+

32
Q

Propranolol

A

impairs cellular entry of K+

33
Q

Forearm exercise during venipuncture can cause

A

erroneously high plasma K+ concentration

34
Q

Hypokalemia can be a result of

A

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

35
Q

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

A

Hyperkalemia

36
Q

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.

A

False; K will increase and Na will decrease

37
Q

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

A

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

38
Q

When maintaining electroneutrality, The amount of Na+ reabsorbed is

A

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

39
Q

Bicarb which helps maintain balance of cell comes from

A

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

40
Q

Bicarbonate diffuses into the plasma while Cl- diffuses into

A

RBC to maintain balance of cell, creating inverse relationship.

41
Q

Sweat chloride can be clinically presented as

A

Chronic obstructive pulmonary disease
Pancreatic insufficiency

42
Q

Swear chloride is caused by

A

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

43
Q

CFTR usually regulates

A

electrolytes transport across epithelial membranes

44
Q

Pilocarpine

A

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

45
Q

The negative electrode in the Gibson Cooke Qpit method has

A

NaCl

46
Q

What is the ratio of bicarbonate to dissolved CO2?

A

bicarbonate to co2 is 20:1

47
Q

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

A

Bicarbonate

48
Q

Increased bicabonate can be seen in

A

Metabolic Alkalosis

49
Q

Decreased bicarbonate can be seen in

A

renal failure and respiratory alkalosis

50
Q

Overall regulation of Magnesium is controlled largely by

A

Kidney

51
Q

The only acceptable coagulant for calcium is

A

Heparin

52
Q

Ionized calcium is proportional to

A

amplitude of heart contraction, decreased concentration impairs myocardial function

53
Q

Lactate is a by product of

A

Anaerobic metabolism

54
Q

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

A

Lactate

55
Q

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

A

Potassium
Bicarb
Phosphate

56
Q

Anion gap is

A

the difference between unmeasured anions and cations