Fluid, Electrolyte, and Acid-Base Balance, Chapter 26 P Besaw
College: First year
Where is the majority of water stored in the human body?
intracellular fluid (ICF) compartment
Select the person in the following list who would have the highest percentage of water in his or her body.
a 6-month-old baby boy
What solute in body fluids determines most of their chemical and physical reactions?
electrolytes
The most abundant cation in intracellular fluid is potassium.
True
Which of the following is an electrolyte?
potassium
The fluid that bathes the cells found in tissues is called __________.
interstitial fluid
What is the most abundant intracellular anion?
HPO42
What is the most abundant intracellular cation?
K+
What is the most common cation found in the interstitial fluid?
Na
Which of the following creates the greatest osmotic pressure?
H3PO4
The movement of fluids between cellular compartments ________.
is regulated by osmotic and hydrostatic forces
In a given day, what is the typical value for water intake?
2500 ml
What accounts for the route through which most fluid is lost in a day?
urine
How much water is generated per day from cellular metabolism?
250 ml
Which of the following is NOT involved in triggering the thirst mechanism?
increase in blood pressure
What receptors does the brain use to detect changes in osmolality?
osmoreceptors
What hormone helps to maintain extracellular fluid (ECF) osmolality when concentrations become too high?
antidiuretic hormone (ADH)
What type of water imbalance increases the amount of fluid in all compartments?
hypotonic hydration
Which of the following conditions promotes edema?
hypoproteinemia
What is the hallmark of hypotonic hydration?
hyponatremia
Which of the following would NOT be expected to lead to edema?
hyponatremia
The role of ADH is to __________.
increase water reabsorption
Under normal circumstances, most water is lost in __________.
urine
The body's water volume is closely tied to a powerful water "magnet." What magnet is referred to here?
ionic sodium
What is the driving force for water intake?
thirst
Which of the following is NOT a risk factor for dehydration?
increased muscle mass
Which of the following regulates the secretion of K+ into the filtrate?
aldosterone
What results from increased levels of aldosterone?
increased Na+ reabsorption
Which of the following does NOT impact how much sodium is reabsorbed?
transport maximum of the renal proximal tubule
PTH (parathyroid hormone) acts on the __________ to __________ Ca2+ reabsorption.
DCT; increase
Potassium balance is controlled mainly by renal mechanisms.
True
Which of the following is NOT a hormone involved in water and electrolyte balance?
thyroxine
Which hormone raises blood calcium levels?
PTH
A patient is discovered to have a strange craving for iron objects. To try to determine the cause, her physician decides to order tests to determine if this patient might have some type of ______.
anemia
Which of the following abnormalities would not be observed in a patient who has Addison's disease?
hypertension
Hypersecretion of aldosterone results in hypokalemia, which causes hyperpolarization of neurons; this in turn results in ______.
the need for a stronger than normal stimulus in order to trigger an action potential
Which of the following is the only logical explanation for why hypocalcemia increases neuromuscular excitability and causes muscle tetany?
Low plasma calcium ion concentration increases the permeability of neuron membranes to sodium ions, thereby causing depolarization that in turn increases the likelihood of action potentials being generated.
Starvation would cause which of the following acid-base conditions? Also, determine what type of compensation (metabolic or respiratory) there would be.
Hint 1.
During starvation, the body must break down fats for metabolism, which causes a buildup of ketones in the body.
metabolic
A patient is admitted to the hospital with the following plasma values: pH = 7.2, pCO2 = 55 mmHg, and HCO3¯ = 30 mEq/L. What is the acid base imbalance?
Hint 1.
Normal pH = 7.35 to 7.45; normal pCO2 = 35 to 45 mmHg; normal HCO3¯ = 22 to 26 mEq/L
respiratory acidosis with metabolic compensation
A patient is admitted to the hospital with the following plasma values: pH = 7.5, pCO2 = 45 mmHg, and HCO3¯ = 30 mEq/L. What is the acid-base imbalance?
Hint 1.
Normal pH = 7.35 to 7.45; normal pCO2 = 35 to 45 mmHg; normal HCO3¯ = 22 to 26 mEq/L
metabolic alkalosis with no compensation
A patient is admitted to the hospital with the following plasma values: pH = 7.2, pCO2 = 25 mmHg, and HCO3¯ = 18 mEq/L. What is the acid base imbalance?
Hint 1.
Normal pH = 7.35 to 7.45; normal pCO2 = 35 to 45 mmHg; normal HCO3¯ = 22 to 26 mEq/L
metabolic acidosis with respiratory compensation
Diarrhea can lead to which acid/base disturbance? Assuming compensation, would it be a metabolic or respiratory compensation?
Hint 1.
Diarrhea causes a loss of bicarbonate ions.
metabolic acidosis with respiratory compensation
Emphysema can lead to which acid/base disturbance? What would be the compensation?
Hint 1.
A patient with emphysema would retain CO2.
respiratory acidosis; kidneys will retain more HCO3 and excrete H+
Of the three buffering mechanisms in the body, which is the strongest?
Hint 1.
This system is also the slowest system.
renal system
The bicarbonate buffer system is one of the chemical buffer systems of the body. How would the bicarbonate buffer system work if sodium hydroxide were added to a solution?
Hint 1.
The bicarbonate buffer system is a mixture of carbonic acid (weak acid) and its salt sodium bicarbonate (weak base).
A hydrogen on carbonic acid would dissociate and join the hydroxyl group on the base to form water and sodium bicarbonate.
The respiratory system is one of the three systems that regulate acid-base balance in the body. How does it work to decrease an acidosis?
Hint 1.
Think about the main function of the respiratory system.
Carbonic acid is broken down into water and CO2; the CO2 is then exhaled.
In a respiratory acidosis the kidney would do which of the following?
Hint 1.
The kidney has three basic functions: filtration, reabsorption, and secretion.
The kidney would reabsorb bicarbonate and secrete hydrogen ions.
Ingesting too much antacid would cause which of the following acid-base disturbances?
Hint 1.
Sodium bicarbonate is an example of an antacid. Ingestion of bicarbonate would cause which acid-base disturbance?
metabolic alkalosis
Vomiting will cause which type of acid-base disturbance?
Hint 1.
Vomiting would cause a loss of HCl acid from the stomach.
metabolic alkalosis
Severe anxiety would cause which type of acid-base disturbance? What would be the compensation?
Hint 1.
Anxiety would cause hyperventilation
respiratory alkalosis; kidneys would excrete HCO3
Which chemical buffer system is the only important system in the extracellular fluid (ECF) that resists short-term changes in pH?
bicarbonate buffer system
In order to buffer a strong acid into a weak acid, which has a less dramatic effect on pH, what chemical should be used as the buffer?
weak base
Which of the following does NOT serve as a source of acids in the body?
aerobic breakdown of glucose
The most important renal mechanism for regulating acid-base balance of the blood involves __________.
maintaining HCO3- balance.
A decrease in blood CO2 levels leads to __________.
an increase in blood pH
The primary buffer of the extracellular fluid (ECF) is the __________.
bicarbonate buffer system
The most common cause of acid-base imbalance is __________.
respiratory acidosis
Which buffer system is the most abundant in the body?
protein
Which organs are the ultimate acid-base regulatory organs?
kidneys
What is the effect of hyperventilation on pH?
respiratory alkalosis
What is the most common cause of acid-base imbalance?
respiratory acidosis
Which age group most commonly has fluid, electrolyte, and acid-base balance issues?
infants