Fluid, Electrolyte, and Acid-base Balance
4. Extracellular fluids in the body consist of __________.
All of the listed responses are correct.
Protein buffer systems do NOT affect __________.
All of these substances are affected by protein buffers.
Which of the following is NOT one of the four basic concepts pertaining to fluid and electrolyte regulation?
Cells are able to move water by the process of active transport.
Which of the following is NOT a basic concept of fluid and electrolyte balance?
All homeostatic mechanisms respond to changes in the ICF.
Which of the following occurs when large amounts of pure water are consumed?
Osmolarities of the two compartments are slightly lower.
Chemoreceptors in the carotid and aortic bodies are sensitive to the __________ of circulating blood.
PCO2
In a protein buffer system, if the pH increases, the carboxyl group (COOH) of the amino acid dissociates and releases __________.
a hydrogen ion
As a result of the aging process, the ability to regulate pH through renal compensation changes as a result of __________.
a reduction in the number of functional nephrons
The elderly have an increased risk of respiratory acidosis because of __________.
a reduction in vital capacity
The concentration of potassium in the ECF is controlled by adjustments in the rate of active secretion __________.
along the distal convoluted tubule of the nephron
The most common problems with electrolyte balance are caused by __________.
an imbalance between sodium gains and losses
Under normal circumstances, during respiratory acidosis the chemoreceptors monitoring the PCO2 of the plasma and CSF will eliminate the problem by calling for __________.
an increase in pulmonary ventilation rates
After a person consumes a meal, the levels of which ion rise in the blood in response to increased acid production in the stomach?
bicarbonate
Sodium levels are figured as a balance between __________.
both absorption of sodium across the digestive epithelium and excretion at the kidney and other sites
Which of the following hormones play(s) a major role in mediating fluid AND electrolyte balance?
both atrial natriuretic peptide and aldosterone
The kidneys respond to respiratory acidosis by __________.
both by excreting hydrogen ions and by generating bicarbonate ions
Which of the following conditions could cause muscle cramps or spasms?
both hyperkalemia and hypocalcemia
The symptoms of low potassium (hypokalemia) include __________.
both muscle weakness and paralysis
The buffering system in the ICF is made up of __________.
both protein buffers and phosphate buffers
Frequent causes of metabolic acidosis include __________.
both severe kidney damage and poorly controlled diabetes mellitus
What is the term for a substance that opposes a change in pH in a solution and can either remove or replace hydrogen ions?
buffer
Abnormal levels of the hormones calcitriol, calcitonin, and parathyroid hormone would lead to an imbalance of which electrolyte?
calcium
Hypercalcemia
calcium concentrations of the ECF in excess of 5.3 mEq/L
Which of the following is NOT a fixed acid?
carbonic acid
Which of the following is a volatile acid and is produced from the combination of carbon dioxide and water?
carbonic acid
Which of the following is NOT one of the major buffer systems of the body?
chloride buffer system
Which of the following does NOT affect fluid levels in the blood?
chloride shift
The major anion in the extracellular fluid compartment is __________, whereas the major intracellular anion is __________.
chloride; biphosphate
What is the most frequent cause of respiratory acidosis?
chronic pulmonary disorders
Alcohol and barbiturate use could cause a desensitization of the respiratory centers, leading to __________.
chronic respiratory acidosis
Aldosterone
conserves sodium and increases sensitivity to salty tastes
Which of the following would NOT be associated with a sensation of increased thirst?
decrease in the production of ADH
The lungs respond to metabolic alkalosis by __________.
decreasing the respiratory rate
When water losses outpace water gains, __________ occurs.
dehydration
Sodium ions enter the ECF by crossing the digestive epithelium via __________.
diffusion and active transport
Angiotensin I and II
elevate systemic blood pressure, promote thirst, and stimulate the release of aldosterone and ADH
Metabolic alkalosis
elevated levels of bicarbonate ions in blood plasma
Interstitial fluid, plasma, and cerebrospinal fluid are all considered __________ fluid.
extracellular
All of the homeostatic mechanisms that monitor and adjust the composition of body fluids respond to changes in the __________.
extracellular fluid
When the amount of water you gain each day is equal to the amount you lose to the environment, you are in __________.
fluid balance
If the ECF is hypertonic with respect to the ICF, water will move __________.
from the cells into the ECF until osmotic equilibrium is restored
What is the term for an abnormally high concentration of sodium in the ECF?
hypernatremia
Respiratory alkalosis
hyperventilation that washes out the carbon dioxide in the blood, increasing the pH
What is the term for an abnormally low concentration of potassium in the ICF?
hypokalemia
When pure water is consumed, the extracellular fluid becomes __________.
hypotonic with respect to the ICF
Which of the following might be a response to respiratory acidosis?
increased respiratory rate
When a normal pulmonary response does NOT reverse respiratory acidosis, the kidneys respond by __________.
increasing the rate of hydrogen ion secretion into the filtrate
The exchange between plasma and interstitial fluid is determined by the relationship between the __________.
net hydrostatic and net colloid osmotic pressures
When water is lost but electrolytes are retained, the osmolarity of the ECF rises and osmosis then moves water __________.
out of the ICF and into the ECF until isotonicity is reached
Blood pH is normally measured at __________.
pH 7.35-7.45
Acidosis can cause all of the following EXCEPT __________.
peripheral vasoconstriction
Hypokalemia
plasma concentrations of potassium below 3.5 mEq/L
Important homeostatic adjustments occur in response to changes in __________.
plasma volume or osmolarity
Which is the most abundant cation in the ICF?
potassium
The primary role of the carbonic acid-bicarbonate buffer system is to __________.
prevent changes in pH caused by organic and fixed acids in the ECF
Metabolic acidosis
producing large quantities of metabolic acids (fixed or organic acids)
Which of the following will NOT cause metabolic acidosis?
production of hydrochloric acid in the stomach
A metabolic alkalosis can be due to __________.
prolonged vomiting
A metabolic alkalosis can occur as a result of __________.
prolonged vomiting
Atrial and brain natriuretic hormone
reduces thirst, lowers blood pressure and plasma volume
What are the two important effects of increased release of ADH?
reduction of urinary water losses and stimulation of the thirst center
Which of the following does NOT cause hypokalemia?
renal failure
A mismatch between carbon dioxide generation in peripheral tissues and carbon dioxide excretion at the lungs is a __________.
respiratory acid-base disorder
Hypercapnia, or an elevation of carbon dioxide in the blood, is a sign of __________.
respiratory acidosis
Hypoventilation causes __________.
respiratory acidosis
What is the most frequent challenge to acid-base equilibrium?
respiratory acidosis
Hyperventilation causes __________.
respiratory alkalosis
Which of the following is NOT a source of water gains?
sensible perspiration
Which is the most abundant cation in the ECF?
sodium
What are the major contributors to the osmolarities of the ECF and the ICF?
sodium and potassium
The most common problems with electrolyte balance are caused by an imbalance between gains and losses of __________.
sodium ions
Which of the following electrically charged substances (ions) are NOT primarily found in the intracellular fluid?
sodium ions
What are the principal ions in the extracellular fluid (ECF)?
sodium, chloride, and bicarbonate
The major cation in the extracellular fluid compartment is __________, whereas the major intracellular cation is __________.
sodium; potassium
Ketone bodies accumulate in the blood during conditions of __________.
starvation
Antidiuretic hormone
stimulates water conservation at the kidneys, and stimulates the thirst center
Which of the following is NOT a buffer system in the ECF or ICF?
sulfate buffer system
What are the most important buffers in the ECF?
the carbonic acid-bicarbonate buffer system
The hemoglobin buffer system helps prevent drastic alterations in pH when __________.
the plasma PCO2 is rising or falling
Which represents the largest volume of water lost each day under normal physiological conditions?
urine
Acute respiratory acidosis can occur in each of the following instances EXCEPT __________.
when normal respiratory function is compromised but compensatory mechanisms have not failed
Chronic diarrhea causes a severe loss of bicarbonate ions, resulting in __________.
metabolic acidosis
Prolonged vomiting and loss of stomach acid cause __________.
metabolic alkalosis
Prolonged vomiting can result in __________.
metabolic alkalosis
Acute respiratory acidosis
most common challenge to acid-base equilibrium, due to hypoventilation and increased CO2 concentrations
Normal ECF pH values are limited to the range between __________.
7.35 and 7.45
Atrial natriuretic peptide __________.
A. blocks aldosterone release B. reduces thirst C. blocks ADH release
Deviations outside of the normal pH range due to changes in hydrogen ion concentrations __________.
A. change the activities of important enzymes B. disrupt the stability of cell membranes C. alter protein structure
High concentrations of hydrogen ions in body tissues can __________.
A. disrupt cell membranes B. change the shape of complex molecules C. break chemical bonds
Disorders that have the potential for disrupting pH balance in the body include __________.
A. heart failure and hypotension B. neural damage and CNS disease C. emphysema and renal failure
The activity that occurs in the body to maintain calcium homeostasis occurs primarily in the __________.
A. kidneys B. bone C. digestive tract
Acidosis is a more common problem than alkalosis because many acids are by-products of metabolic reactions. Which of the following acids fits that description?
A. lactic acid B. carbonic acid C. sulfuric acid
The major causes of metabolic acidosis include which of the following?
A. production of a large number of fixed or organic acids B. impaired ability to excrete H+ at the kidneys C. a severe bicarbonate loss
Atrial natriuretic peptide hormone __________.
A. reduces thirst B. blocks the release of ADH C. blocks the release of aldosterone
Hypocapnia __________.
A. refers to low levels of carbon dioxide in the blood B. can be caused by hyperventilation, which can be used to counter respiratory acidosis C. is a self-correcting condition when caused by hyperventilation
Pulmonary and renal mechanisms support the buffer systems by __________.
A. secreting or generating hydrogen ions B. generating additional buffers when necessary C. controlling the excretion of acids and bases
Angiotensin II produces a coordinated elevation in the extracellular fluid volume by __________.
A. stimulating thirst B. causing the release of ADH C. triggering the secretion of aldosterone
Treatment for hyperkalemia includes the __________.
A. use of appropriate diuretics B. administration of buffers such as sodium bicarbonate C. infusion of hypotonic solution
Which of the following occurs when an individual loses body water?
Plasma volume decreases, and electrolyte concentrations rise.
Which of the following hormones causes the conservation of sodium in the kidneys?
aldosterone
Renin
activates angiotensin I
Which of the following is NOT a response to respiratory acidosis?
inhibition of arterial and CSF chemoreceptors
The body content of water or electrolytes will rise if __________.
intake exceeds outflow
Which of the following is NOT an ECF?
intracellular fluid
Potassium ions are found in the highest concentrations in which of the following fluid compartments?
intracellular fluid (ICF)
What is an electrolyte?
ions released through the dissociation of inorganic compounds
Whenever the rate of sodium intake or output changes, there is a corresponding gain or loss of water that tends to __________.
keep the sodium concentration constant
Which of the following body organs has the greatest measure of control over body fluid and composition levels?
kidneys
What is the most frequent cause of metabolic alkalosis?
loss of acids, especially through vomiting
Increasing or decreasing the rate of respiration can have a profound effect on the buffering capacity of body fluids by __________.
lowering or raising the PCO2
Respiratory alkalosis develops when respiratory activity __________.
lowers plasma PCO2 to below-normal levels