Chp. 24 Water, Electrolyte, and Acid-Base Balance
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Blood plasma osmolarity is higher than intracellular fluid osmolarity.
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False
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In a state of water balance, average daily fluid gains and losses are equal.
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True
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Fluid intake is governed mainly by hypothalamic receptors called osmoreceptors.
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True
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The kidneys secrete ADH in response to dehydration.
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False
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Hypovolemia refers to a reduction in total body water while maintaining normal osmolarity.
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True
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Aldosterone promotes potassium excretion.
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True
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Natriuretic peptides promote sodium and potassium excretion.
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False
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Hyponatremia is usually a result of hypotonic hydration.
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True
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Hypocalcemia causes muscle weakness, whereas hypercalcemia causes potentially fatal muscle tetanus.
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False
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Chloride homeostasis is regulated as a side effect of sodium homeostasis.
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True
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A buffer system converts a weak acid or base into a strong one.
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False
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The three physiological buffer systems are urinary, digestive, and respiratory.
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False
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The kidneys neutralize more acid or base than any other buffer system.
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True
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Acidosis is a pH lower than 7, whereas alkalosis is a pH higher than 7.
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False
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Uncompensated alkalosis is a pH imbalance that can only be corrected with clinical intervention.
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True
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Where is the greatest volume of water in the body found?
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Intracellular fluid (ICF)
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What determines osmosis from one fluid compartment to another?
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The relative concentration of solutes in each compartment
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In which compartment would fluid accumulate in edema?
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Tissue (interstitial) fluid
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Most body water intake is from __________, whereas most body water lost is via __________.
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drinking; urine
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Fluid intake is governed mainly by hypothalamic neurons called __________.
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osmoreceptors
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What is the function of antidiuretic hormone?
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It promotes water conservation.
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Water output is largely controlled by varying ___________.
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urine volume
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Which of the following occurs when blood volume and pressure become too high?
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ADH release is inhibited.
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Which of the following can prolonged exposure to cold weather lead to?
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Increased respiratory water loss
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In response to dehydration, osmoreceptors stimulate the secretion of __________.
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ADH
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A hemorrhage results in which of the following?
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A decrease in water volume without significantly affecting the osmolarity
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Long-term inhibition of thirst is mostly associated with which of the following?
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A drop in blood osmolarity
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What is the principal cation of the ECF?
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Na+
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Where are cells with aldosterone receptors found?
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Distal convoluted tubule
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What is the function of aldosterone?
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It increases Na+ reabsorption and K+ secretion.
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Hypernatremia is a plasma __________ concentration above normal.
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Na+
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Which of the following is not caused by hypernatremia?
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A reduction in plasma volume
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What is the most significant solute in determining the distribution of water among fluid compartments?
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Na+
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Which of the following does not stimulate aldosterone secretion?
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High blood sodium concentration
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Women have a tendency to retain water during part of the menstrual cycle because estrogen mimics the action of what?
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Aldosterone
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What is the most abundant cation in the ICF?
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K+
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What is the total body water (TBW) content of a 70 kg young male?
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40 L
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What is the greatest determinant of the intracellular water volume?
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K+
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Which of these conditions is not a result of hyperkalemia?
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The resting membrane potential is more negative.
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Which of the following occurs with hypokalemia?
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Cells are hyperpolarized.
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Hypokalemia can result from all of the following except __________.
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aldosterone hyposecretion
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What is the most abundant anion in the ECF?
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Cl-
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Chloride homeostasis is achieved mainly as a result of ____________ homeostasis.
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Na+
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Which of the following is not a role of calcium in the body?
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It is a significant component of nucleic acids.
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How is calcium concentration in the body regulated?
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By hormones
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Which of the following accurately describes the inorganic phosphates (Pi) of the body fluids?
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They form crystals with calcium in the presence of calsequestrin.
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Which of the following is a result of phosphate excretion from the body?
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An increase in free calcium ions in the ECF
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Which of the following represents the complete chemical reaction for the bicarbonate buffer system?
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CO2 + H2O PictureH2CO3 PictureHCO3- + H+
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What is the normal pH of tissue fluid?
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7.35-7.45
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What are the major chemical buffer systems of the body?
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The bicarbonate, phosphate, and protein
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What protein is the most important buffer in blood plasma?
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Albumin
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What protein is the most important buffer in erythrocytes?
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Hemoglobin
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Which of the following characterizes a weak base?
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It binds a little H+ and has a weak effect on pH.
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When the renal tubules secrete hydrogen ions into the tubular fluid, they __________ at the same time.
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reabsorb sodium
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Which buffer system accounts for 75% of all chemical buffering in the body fluids?
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The protein buffer system
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The bicarbonate buffer system would not work very well in the human body if not for the action of the respiratory system, which ___________.
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expels CO2 produced by the buffer system
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Which of the following describes an antiport system on the basal side of renal tubule cells?
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It exchanges K+ for Na+.
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Proteins can buffer a drop in pH with their ___________ side groups and can buffer an increase in pH with their __________ side groups.
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-NH2; -COOH
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Acidosis has what effect on the resting membrane potential of nerve cells?
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It causes hyperpolarization.
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How do the kidneys compensate respiratory acidosis?
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By secreting more hydrogen ions
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Breathing into and out of a paper bag for a long period of time will lead to __________.
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respiratory acidosis
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An excessive intake of antacids can lead to which of the following?
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Metabolic alkalosis
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Chronic vomiting can lead to which of the following?
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Metabolic alkalosis
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Emphysema can lead to which of the following?
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Respiratory acidosis
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A patient suffering from diabetic acidosis would display which of the following symptoms?
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Hyperventilation
