Electrolytes and Acid-Base Balance

Question 1

Active transport

Answer 1

requires energy to move ions across cellular membranes

Question 2

Cation

Answer 2

electrolytes with a positive charge; migrate towards the cathode

Question 3

Electrolyte

Answer 3

ions (minerals) capable of carrying an electric charge

Question 4

sodium

Answer 4

involved in volume and osmotic regulation; most abundant cation in the ECF; largely determines the osmolality of the plasma

Question 5

chloride

Answer 5

involved in volume and osmotic regulation; acid-base balance; major extracellular anion

Question 6

Diffusion

Answer 6

passive movement of ions (no energy consumed) across a membrane and is dependent on size and charge of the ion

Question 7

potassium

Answer 7

involved in volume and osmotic regulation; myocardial rhythm and contractility; neuromuscular excitability; acid-base balance; major intracellular cation; affects H+ concentration in the blood

Question 8

Extracellular Fluid (ECF)

Answer 8

intravascular ECF (plasma) and interstitial cell fluid that surrounds the cells in the tissue

Question 9

calcium

Answer 9

myocardial rhythm and contractility; cofactor in enzyme activation; blood coagulation; neuromuscular excitability; PTH, vitamin D, and calcitonin regulate Ca2+

Question 10

zinc

Answer 10

cofactor in enzyme activation

Question 11

bicarbonate

Answer 11

acid-base balance

Question 12

phosphate

Answer 12

production and use of ATP from glucose

Question 13

Intracellular fluid

Answer 13

Fluid inside the cells and accounts for about 2/3 of total body water

Question 14

Osmolality

Answer 14

concentration of solutes (mmol) per kilogram of solute; ; parameter to which the hypothalamus responds

Question 15

Normal Osmolality

Answer 15

275-295 mOsm/kg of plasma H2O

Question 16

Arginine Vasopressin Hormone

Answer 16

aka antidiuretic hormone; secretion is stimulated by increase in osmolality of blood; deficit of water or increase in sodium ion

Question 17

factors affecting blood volume

Answer 17

1. atrial natriuretic peptide (ANP) promotes Na+ excretion in the kidney (acts together with B-type natriuretic peptide to regulate blood pressure and fluid balance);
2. volume receptors independent of osmolality stimulate the release of AVP, which conserves water by renal reabsorption;
3. glomerular filtration rate (GFR) increases with volume expansion and decreases with volume depletion;
4. an increased plasma Na+ will increase urinary Na+ (and therefore water) excretion and vice versa

Question 18

determination of osmality

Answer 18

specimen: serum or urine
method: osmometers operating by freezing point depression
units: milliosmoles per kilogram

Question 19

Osmolal gap

Answer 19

difference between measured and calculated osmolality

Question 20

Osmolality calculation

Answer 20

2Na + (glucose(mg/dL)/20)+(BUN(mg/mL)/3) or 1.86Na + (glucose/18)+ (BUN/2.8)+9

Question 21

Hyponatremia

Answer 21

serum/plasma levels less than 135 mmol/L; caused by increased Na+ loss, increased water retention, or water imbalance; most cases have low or decreased osmolality; if osmolality is normal may be due to increase of non sodium cations (i.e. potassium, magnesium, calcium); symptoms include nausea and vomiting, muscular weakness, headache, lethargy, and ataxia

Question 22

Hypernatremia

Answer 22

increased Na+ level in plasma due to decreased water intake, or increased Na+ intake; rarely seen clinically; causes hyperosmolar state; symptoms include altered mental status, lethargy, irritability, restlessness, seizures, muscle twitching, hyper reflexes, fever

Question 23

Hypokalemia

Answer 23

decreased K+ in serum (below lower limit of reference range); decreased H+ in ECF; alkalosis; caused by gastrointestinal loss, renal loss, cellular shift, or decreased intake; symptoms include weakness, fatigue, and constipation; can lead to paralysis

Question 24

Hyperkalemia

Answer 24

increased K+ due to decreased renal excretion, cellular shift (i.e. acidosis), increased intake, or artifactual (i.e. sample hemolysis, thrombocytosis, or tourniquet); can lead to cardia arrhythmias and possible cardiac arrest

Question 25

magnesium

Answer 25

about 1/3 of plasma magnesium is bound to protein (primarily albumin); essential cofactor of 300+ enzymes, trans cellular ion transport, neuromuscular transmission, synthesis of carbs, proteins, lipids, and nucleic acids, and release of and response to certain hormones

Question 26

hypomagnesemia

Answer 26

decreased Mg(2+); caused mostly by reduced intake, decreased absorption (pancreatitis), increased excretion through renal, endocrine or drug induced (diuretics) means

Question 27

hypermagnesemia

Answer 27

increased Mg(2+) due to decreased excretion, increased intake, or dehydration

Question 28

hypocalcemia

Answer 28

decreased Ca(2+) due to decreased or no PTH, hypomagnesemia, acute pancreatitis;

Question 29

Anion Gap

Answer 29

Na+ - (Cl- + HCO3-) or (Na+ +K+) - (Cl- + HCO3-)

Question 30

Acidemia

Answer 30

an increase in the hydrogen ion concentration of the blood, resulting in a decrease in pH; increased pCO2 (primary acidosis) or decreased HCO3- (non respiratory or metabolic acidosis)

Question 31

Alkalemia

Answer 31

a decrease in the hydrogen ion concentration in the blood, resulting in an increase in pH; decreased pCO2 (primary alkalosis) or increased HCO3- (non respiratory or metabolic alkalosis)

Question 32

compensation

Answer 32

response to maintain acid-base homeostasis by altering the factor not associated with the primary process; fully compensated indicates pH is returned to normal; partially compensated implies pH is approaching normal

Question 33

Oxygen saturation

Answer 33

indicates that amount of oxygen traveling through your body with your red blood cells. Normal oxygen saturation is usually between 95% and 100% for most healthy adults