Adv. Clinical Chemistry Unit 5 - Electrolytes

Name for a positively charged ion.

cation

Name for a negatively charged ion.

anion

Cations move toward the ________ charged _________.

negatively; cathode

Anions move toward the ________ charged ________.

positively; anode

Term for liquid found inside the cells.

intracellular fluid

Term for liquid found outside the cells.

extracellular fluid

Pressure exerted by plasma proteins to draw water into the vessels from the interstitial space or hold water in vessels.

colloid osmotic pressure

Pressure exerted by the heart that drives water out of vessels into the interstitial fluid/tissues.

hydrostatic pressure

Form of moving electrolytes that requires energy.

active transport

Form of moving electrolytes that does not require energy.

diffusion

________ occurs when there is less fluid in the vessels and more in the interstitial space.

edema

Edema is caused by a decrease in _________ pressure or an increase in ________ pressure.

colloid osmotic; hydrostatic

This enzyme is produced by the kidney and is released in response to a decrease in blood volume or blood pressure.

renin

Renin converts __________ into _________.

angiotensinogen; angiotensin I

Angiotensin I becomes angiotensin II in the _________.

lungs

Angiotensin II increases blood pressure by acting as a ___________ and stimulating the release of __________.

vasoconstrictor; aldosterone

This hormone stimulates the kidney into retaining sodium.

aldosterone

What three peptides aid in the regulation of water and sodium metabolism?

ANP/BNP/CNP

What two naturetic peptides can be used to monitor CHF?

ANP/BNP

What two electrolytes are the major contributors to plasma osmality?

sodium/chloride

What method is usually used to measure osmolality.

freezing point depression

What samples can be used to measure osmolality?

urine/serum/stool (watery)

What are the first two primary responses in the body to an increased plasma osmolality?

thirst/production of ADH

This hormone stimulates the kidney into retaining more water.

ADH

Formula for calculating osmolality:

1.86[Na] + (glucose/18) + (BUN/2.8) + 9

A osmolality gap that is _________ indicates the presence of other substances in the blood.

> 10 mOsm/kg

What unit is generally used to express osmolality?

mOsm/kg

Sodium is the major (extracellular/intracellular) (anion/cation).

extracellular cation

What hormonal disorder can lead to hypernatremia?

diabetes insipidus

Potassium deficiency can cause (hyponatremia/hypernatremia).

hyponatremia

Hypoadrenalism can cause (hyponatremia/hypernatremia).

hyponatremia

Name four conditions that result in an increase in water that leads to hyponatremia:

renal failure/nephrotic syndrome/hepatic cirrhosis/CHF

Potassium is the major (extracellular/intracellular) (anion/cation).

intracellular cation

What are the two main mechanisms responsible for regulating potassium?

kidney/cellular exchange

Cushings syndrome can cause (hypokalemia/hyperkalemia).

hypokalemia

Addison's disease can cause (hypokalemia/hyperkalemia).

hyperkalemia

Hypomagnesemia can cause (hypokalemia/hyperkalemia).

hypokalemia

Acidosis can cause (hypokalemia/hyperkalemia).

hyperkalemia

Alkolosis can cause (hypokalemia/hyperkalemia).

hypokalemia

An insulin overdose can cause (hypokalemia/hyperkalemia).

hypokalemia

Acute leukemia can cause (hypokalemia/hyperkalemia).

hypokalemia

Large doses of laxitives can cause (hypokalemia/hyperkalemia).

hypokalemia

Why should potassium samples contain no hemolysis?

clotting process releases K from platelets

Name two unique errors in blood collection that can affect potassium levels?

tourniquet on too long/storing on ice

Chloride is the major (extracellular/intracellular) (anion/cation).

extracellular anion

This electrolyte mainly responsible for electric neutrality is...

chloride

What two mechanisms are primarily responsible for chloride regulation.

kidney/chloride shift

What four conditions result in hypochloremia?

metabolic alkalosis/renal failure/respiratory acidosis/prolonged vomiting

What three conditions result in hyperchloremia?

metabolic acidosis/excess loss of HCO3 through GI tract/renal tubular acidosis

What specimens can be used to measure chloride

serum/plasma/urine (24 hour)/sweat

This method of measuring chloride uses silver ions.

amperometric titration

This method of measuring chloride uses mercury ions to form a blue compound.

mercury titration

This method of measuring chloride uses mercury and ferric nitrate to form a red compound.

ferric nitrate

Sweat chloride can be used to diagnose ________, if levels are _________.

cystic fibrosis; > 60 mmol/L

What method of measuring electrolytes is capable of quantifying Na, K, and Cl.

ion specific electrode

The ___________ electrode in the ISE method creates a constant potential.

reference

The _________ electrode is sensitive to the analyte being quantified.

measuring

Name the three parts of the ISE reference electrode:

mercury chloride electrode/saturated KCl solution/liquid junction

Name the three parts of the ISE measuring electrode:

silver-silver chloride electrode/inner electrolyte solution/ion selective membrane

What are the two types of ISE measurement?

direct (undiluted sample)/indirect (diluted sample)

What is the 2nd most abundant anion in the ECF?

bicarbonate

What is bicarbonates major function?

buffering system

What electrolyte exchanges places with bicarbonate so it can leave/enter RBCs.

chloride

What main mechanism is responsible for regulating bicarbonate?

ventilation

Bicarbonate is decreased in what two conditions?

metabolic acidosis/renal failure

Bicarbonate is increased in what four conditions?

metabolic alkalosis/alkalosis from vomiting/excessive intake of alkali/compensated respiratory acidosis

What samples can be used to measure bicarbonate

plasma (venous)/serum (venous)/arterial whole blood (for blood gases)

What two methods can be used to measure bicarbonate?

ISE/colorimetric

What formula is used to calculated the anion gap?

(Na + K) - (Cl + HCO3)

A low anion gap indicates a decrease in unmeasured _________ and an increase in unmeasured ________.

anions; cations

A low anion gap could indicate what condition?

multiple myeloma

A high anion gap indicates a decrease in unmeasured _______ and an increase in unmeasured ________.

cations; anions

What conditions can lead to a high anion gap?

methanol toxicity/uremia (renal failure)/diabetes mellitus (in ketoacidosis)/paraldehyde toxicity/isoniazid or iron toxicity/lactic acidosis/ethylene glycol toxicity/salicylate toxicity

Most magnesium in the body is found within...

bone

This electrolyte acts as a co activator to more than 300 enzymes.

magnesium

What mechanism is primarily responsible for regulation of magnesium?

kidney

PTH (increases/decreases) renal absorption of Ca and Mg.

increases

Aldosterone (increases/decreases) renal absorption of Mg.

decreases

Thyroxine (increases/decreases) renal absorption of Mg.

decreases

What endocrine disorder can lead to hypomagnesemia?

diabetes mellitus

This electrolyte is decreased with chronic alcoholism.

magnesium

Hypoaldosteronism can cause (hypomagnesemia/Hypermagnesemia).

Hypermagnesemia

Hypothyroidism can cause (hypomagnesemia/hypermagnesemia).

hypermagnesiemia

Excessive intake of antacids can cause (hypomagnesemia/hYpermagnesemia).

hYpermagnesemia

Bone cancer can cause (hypomagnesemia/hyper-magnesemia).

hyper-magnesemia

What samples can you use to test magnesium levels?

serum (non hemolyzed)/lithium heparin plasma/urine (timed)

What is the most abundant electrolyte in the body?

calcium

Almost all of this electrolyte is found within the bones.

calcium

Magnesium is primarily an (extracellular/intracellular) (anion/cation).

extracellular cation

What three mechanisms are responsible for regulating calcium levels?

PTH/vitamin D/calcitonin

PTH (increases/decreases) serum levels of calcium.

increases

Vitamin D (increases/decreases) serum levels of calcium.

increases

Calcitonin (increases/decreases) serum levels of calcium.

decreases

What four conditions can lead to hypercalcemia?

PTH/hyperthyroidism/tumors/renal failure

What three conditions can lead to hypocalcemia?

hypoparathyroidism/hypomagnesemia/pancreatitis

What two tubes should you avoid when collecting a sample for calcium?

EDTA/oxalate

What samples can you use to measure calcium?

serum/lithium heparin plasma

Specimins for ionized calcium must be collected _________.

anaerobically

Urine samples for measuring Ca should be preserved with...

HCl

What substance is combined with calcium so it can be measured colorimetrically? What color does it produce?

o-cresophthalein; red