Deck 15: A--Fluid and Acid-Base Balance

Question 1

Extracellular fluid

A) constitutes a greater percentage of total body water than does intracellular fluid
B) osmolarity must be regulated to prevent an acid-base imbalance because the hydrogen ions might become too concentrated or too dilute in the body fluids
C) volume must be regulated to prevent the cells from swelling or shrinking
D) more than one of these
E) none of these

Answer 1

E

Question 2

Extracellular fluid

A) includes plasma
B) includes interstitial fluid
C) constitutes a smaller percentage of total body water than does intracellular fluid
D) includes lymph
E) all of these

Answer 2

E

Question 3

The primary ECF cation is ____, and the primary ICF cation is ____.

A) K⁺; Na⁺
B) K⁺; Ca²⁺
C) Ca²⁺; Na⁺
D) Na⁺; K⁺
E) Na⁺; Ca²⁺

Answer 3

D

Question 4

The primary electrolyte in the extracellular fluid is

A) calcium ion
B) chloride
C) phosphate
D) potassium ion
E) sodium ion

Question 5

A ____ exists when total body input of a particular substance equals its total body output.

A) positive balance
B) negative balance
C) stable balance
D) state of equilibrium
E) steady state

Question 6

The ion in greatest concentration within the cytoplasm is

A) calcium ion
B) chloride
C) phosphate
D) potassium ion
E) sodium ion

Question 7

The unequal distribution of sodium and potassium between the ICF and ECF

A) results from sodium being pumped in and potassium being pumped out of cells
B) results from sodium being pumped out and potassium being pumped into cells
C) results from ATPase activity
D) results from sodium being pumped in and potassium being pumped out of cells, and from sodium being pumped out and potassium being pumped into cells
E) results from sodium being pumped out and potassium being pumped into cells, and from ATPase activity

Question 8

Interstitial fluid

A) is the largest component of the extracellular fluid
B) is the true internal environment of the body
C) represents a larger percentage of total body weight than does intracellular fluid
D) includes the cytosol
E) is the largest component of the extracellular fluid and the true internal environment of the body

Question 9

The tissue in the body containing the lowest percentage of water is

A) skin
B) skeletal muscle
C) muscle
D) smooth muscle
E) adipose (fat)

Question 10

When large amounts of pure water are consumed

A) The volume of the ICF will decrease.
B) The volume of the ECF will decrease.
C) The ECF becomes hypertonic to the ICF.
D) Osmolarities of the ICF and ECF will drop.
E) None of these.

Question 11

The ICF contains about ____ of the total water of the body.

A) 1/10
B) 1/4
C) 1/2
D) 2/3
E) 5/6

Question 12

The barrier between the plasma and interstitial fluid

A) is the blood vessel walls
B) is the plasma membrane
C) transports materials between these two fluid compartments by both passive and active means
D) is the blood vessel walls and the plasma membrane
E) all of these

Question 13

Transcellular fluid

A) is the sum of fluid within all of the cells
B) consists of a number of small specialized fluid volumes, all of which are secreted by specific cells into a particular body cavity to perform a specialized function
C) plays a crucial role in fluid balance
D) includes the lymph
E) lies in the spaces between the cells

Question 14

Select the transcellular fluid that serves as a shock absorber in the joints.

A) intraocular
B) pericardial
C) peritoneal
D) pleural
E) synovial

Question 15

Variation in percent body water among individuals is primarily due to differences in

A) amount of adipose tissue
B) total muscle mass
C) vasopressin secretion
D) drinking habits
E) glomerular filtration rate

Question 16

The primary anion of the ECF is

A) bicarbonate
B) chloride
C) phosphate
D) sodium ion
E) potassium ion

Question 17

The major source of water loss from the body is

A) feces
B) insensible respiratory loss
C) insensible skin loss
D) sweat
E) urine

Question 18

The largest percentage of water is located in what "compartment"?

A) synovial fluids
B) plasma
C) interstitial fluids
D) intracellular fluids
E) extracellular fluids

Question 19

The component that constitutes the largest percentage of body weight is

A) protein
B) H₂O
C) Na⁺
D) carbohydrate
E) phospholipid

Question 20

When water is lost from the ECF but electrolytes are retained:

A) Both ECF and ICF become more dilute.
B) Osmosis moves water from the ICF to the ECF.
C) The osmolarity of the ECF drops.
D) There is an increase in the volume of the ICF.
E) Water levels remain the same.

Question 21

The baroreceptor reflexes affect sodium balance by

A) causing release of renin
B) causing the release of vasopressin
C) lowering GFR through vasoconstriction of afferent arterioles
D) lowering GFR through vasodilation of afferent arterioles
E) none of these

Question 22

All of the following will occur during water intoxication except

A) ICF hypotonicity
B) ECF hypotonicity circulatory
C) excess free water retention
D) water movement from ICF to ECF
E) overhydration

Question 23

Ingesting more salt would

A) increase the plasma's osmolarity
B) make the plasma hypotonic to blood cells
C) cause a decrease in vasopressin secretion
D) increase the plasma's osmolarity and make the plasma hypotonic to blood cells
E) make the plasma hypotonic to blood cells and cause a decrease in vasopressin secretion

Question 24

The main control for salt balance is

A) control of salt intake
B) control of salt output in the sweat
C) control of salt output in the feces
D) control of salt output in the urine
E) regulation through salt hunger

Question 25

Which of the following are compensatory measures for a fall in arterial blood pressure?

A) increased cardiac output
B) a shift of fluid out of the interstitial compartment into the vasculature
C) a reduction in the urinary excretion of salt and accompanying fluid
D) increased total peripheral resistance as a result of the baroreceptor reflex
E) all of these

Question 26

The most important factor in the long-term regulation of ECF volume is

A) maintenance of salt balance
B) maintenance of water balance
C) thirst
D) the baroreceptor reflex
E) fluid shifts between the interstitial fluid and plasma

Question 27

If an individual is overhydrated:

A) H₂O will move by osmosis into the cells.
B) Both the ECF and ICF compartments will be hypotonic after the fluid shift has occurred.
C) Symptoms might include confusion, headache, lethargy, weakness, and edema.
D) H₂O will move by osmosis into the cells and symptoms might include confusion, headache, lethargy, weakness, and edema.
E) All of these.

Question 28

Diabetes insipidus

A) is due to excess vasopressin secretion
B) is due to vasopressin deficiency
C) gives rise to hypertonicity of the ECF
D) is due to excess vasopressin secretion and gives rise to hypertonicity of the ECF
E) is due to vasopressin deficiency and gives rise to hypertonicity of the ECF

Question 29

Osmotic activity across plasma membranes is most closely related to

A) the distribution of proteins in the membrane
B) ionic differences between the ECF and ICF
C) differences in protein composition between the ECF and ICF
D) the distribution of proteins in the membrane and ionic differences between the ECF and ICF
E) the distribution of proteins in the membrane and differences in protein composition between the ECF and ICF

Question 30

Sodium is directly or indirectly controlled through all these mechanisms except

A) the baroreceptor reflexes
B) the renin-angiotensin mechanism
C) aldosterone activity
D) changes in GFR
E) by altering gastrointestinal absorption

Question 31

The major importance of regulating ECF osmolarity is

A) to help maintain blood pressure
B) to prevent the urine from becoming too concentrated
C) to prevent fluid shifts between the cells and the extracellular fluid, which could produce profound symptoms as the cells swell or shrink
D) to prevent spontaneous depolarization of nerve and muscle cell membranes because of shifts in Na⁺ balance
E) to prevent an acid-base imbalance if the hydrogen ions were to become too concentrated or too dilute in the body fluids

Question 32

The vast majority of the extracellular fluid's osmotic activity is contributed by

A) plasma proteins
B) Na⁺ and its attendant anions
C) K⁺ and its attendant anions
D) Ca²⁺ and its attendant anions
E) red blood cells

Question 33

The primary reason that extracellular fluid volume must be closely regulated is

A) to prevent changes in ICF osmolarity
B) to maintain adequate urine formation
C) to maintain proper blood pressure
D) to prevent cells from swelling or shrinking
E) to allow changes in ICF volume

Question 34

Which statement is correct?

A) During hypotonicity, water enters the cells by osmosis.
B) The only cause of hypotonicity is drinking excess fluid.
C) Hypotonicity is a major consequence of diabetes mellitus, which is a deficiency of vasopressin.
D) Hypotonicity is usually associated with a negative water balance.
E) Common symptoms of hypotonicity include dry skin and sunken eyeballs.

Question 35

When the ECF becomes hypertonic, water

A) movement is unaffected
B) moves into the cells by active transport
C) moves into the cells by osmosis
D) moves out of the cells by active transport
E) moves out of the cells by osmosis

Question 36

Why would eating a very salty snack make you thirsty?

A) It would cause decreased ECF volume.
B) It would decrease the osmolarity of the ECF.
C) It would inhibit the hypothalamic osmoreceptors.
D) It would stimulate the hypothalamic osmoreceptors.
E) It would immediately cause more urine output.

Question 37

A drop in arterial blood pressure would trigger

A) decreased GFR
B) release of aldosterone
C) increased sodium reabsorption
D) decreased chloride excretion
E) all of these

Question 38

If an individual becomes dehydrated

A) Increased facultative reabsorption of water occurs.
B) Urinary output increases.
C) Vasopressin secretion is decreased.
D) The ECF osmolarity becomes hypotonic.
E) All of these.

Question 39

If the ECF's osmolarity increases

A) Water will shift from the ICF into the ECF.
B) Water will not shift between the ECF and the ICF.
C) Water will move from the ECF into the ICF.
D) Vasopressin secretion will decrease.
E) Potassium and sodium will compensate.

Question 40

Which of the following is not a potential cause of hypertonicity in the body?

A) water deprivation
B) heavy sweating
C) excess vasopressin secretion
D) diabetes insipidus
E) severe diarrhea

Question 41

A pH of 4 is ____ times as acidic as a pH of 7.

A) 10
B) 100
C) 1,000
D) 10,000
E) 100,000

Question 42

Insensible water loss includes loss

A) during cellular metabolism
B) from the lungs
C) from sweat
D) in the feces
E) none of these

Question 43

The pH of a solution with a H⁺ concentration of 0.0000567 is

A) between 4 and 5
B) between 5 and 6
C) between 6 and 7
D) between 7 and 8
E) none of these

Question 44

pH is

A) equal to log 1/[H⁺]
B) equal to pK + log [HCO₃^-]/[CO₂]
C) low when acidosis is present
D) both equal to log 1/[H⁺] and pK + log [HCO₃^-]/[CO₂]
E) all of these

Question 45

The thirst mechanism is invoked when

A) the plasma osmolarity increases
B) the plasma osmolarity decreases
C) hypothalamic osmoreceptors are activated
D) the plasma osmolarity increases and the plasma osmolarity decreases
E) the plasma osmolarity increases and hypothalamic osmoreceptors are activated

Question 46

Metabolic water

A) results from cellular respiration
B) is roughly 15% of daily water input
C) production increases during times of dehydration to compensate for water loss
D) results from cellular respiration and is roughly 15% of daily water input
E) results from cellular respiration, and its production increases during times of dehydration to compensate for water loss

Question 47

Vasopressin

A) is released when hypothalamic osmoreceptors are activated
B) promotes water secretion in the kidneys
C) causes increased systemic vasoconstriction
D) is released when hypothalamic osmoreceptors are activated and causes increased systemic vasoconstriction
E) all of these

Question 48

Which statement is incorrect?

A) Acids can dissociate in solution to yield free hydrogen ions and anions.
B) All substances that contain hydrogen are considered to be acids.
C) A strong acid has a greater tendency to dissociate than a weak acid.
D) The extent of dissociation for a given acid is a constant, K.
E) Only free hydrogen ions contribute to the acidity of a solution.

Question 49

When isotonic fluid is added to the ECF, fluid

A) will shift from the ICF into the ECF
B) will not shift between the ECF and ICF
C) will shift from the ECF into the ICF
D) in the ECF will become hypotonic
E) will shift from the ECF into the ICF and in the ECF will become hypotonic

Question 50

Hypothalamic osmoreceptors are nearest to

A) angiotensin-secreting cells
B) carotid baroreceptors
C) the adrenal cortex
D) the adrenal medulla
E) vasopressin-secreting cells

Question 51

Salt balance in humans

A) depends primarily upon control of Na⁺ intake through salt hunger
B) depends primarily upon control of Na⁺ output by the kidneys
C) is poorly regulated
D) depends upon Na⁺ secretion by the kidneys
E) is not affected by aldosterone secretion

Question 52

Select the incorrect statement about acids.

A) Carbohydrates are acidic.
B) HCl is one example.
C) They can be strong or weak.
D) They dissociate to produce anions.
E) They dissociate to produce free hydrogen ions.

Question 53

Given the following information, what is the pH? ratio of [HCO₃]/[CO₂] = 20/0.5
PK = 6.1
Log of 10 = 1.0
Log of 20 = 1.3
Log of 40 = 1.6

A) pH = 7.0
B) pH = 7.4
C) pH = 7.1
D) pH = 7.7
E) It is impossible to determine the pH with the information provided.

Question 54

The amount of Na⁺ excreted in the urine equals the amount of Na⁺ ____ minus the amount of Na⁺ ____.

A) filtered; reabsorbed
B) ingested; filtered
C) ingested; metabolically consumed
D) ingested; placed in storage
E) secreted; reabsorbed

Question 55

Which acid below would be considered a strong acid?

A) one with a dissociation constant (K) = 0.05
B) one with a dissociation constant (K) = 0.10
C) one with a dissociation constant (K) = 0.47
D) one with a dissociation constant (K) = 0.53
E) one with a dissociation constant (K) = 0.99

Question 56

Which statement about hypotonicity of the body fluids is incorrect?

A) Diabetes insipidus can cause it.
B) It occurs when excess free H₂O is present.
C) Drowsiness, headache, confusion, lethargy, weakness, and edema are symptoms associated with it.
D) Drinking excess fluid is a cause of it.
E) The cells become swollen because of it.

Question 57

pH

A) equals the logarithm to the base 10 of the reciprocal of the hydrogen-ion concentration
B) can be calculated if the HCO₃^- and CO₂ concentration in the body fluids is known, even if the H⁺ concentration is unknown
C) is higher in arterial blood than venous blood
D) equals the logarithm to the base 10 of the reciprocal of the hydrogen-ion concentration, and can be calculated if the HCO₃^- and CO₂ concentration in the body fluids is known, even if the H⁺ concentration is unknown
E) all of these

Question 58

What is the primary regulatory mechanism to maintain water balance in the body?

A) control of intake through thirst
B) control of sweating
C) control of output through regulation of urine production by the kidney
D) oral metering
E) control of insensible water loss

Question 59

Which is a source of water input?

A) fluid intake
B) ingested food
C) chemical reactions within the cells that convert food and O₂ into energy
D) all of these
E) fluid intake and ingested food

Question 60

When there is excess Na⁺ in the body

A) The plasma volume is expanded, and arterial blood pressure is increased.
B) As a compensatory measure, the GFR is increased.
C) As a compensatory measure, aldosterone secretion is increased to increase the amount of Na⁺ reabsorbed.
D) The plasma volume is expanded and arterial blood pressure is increased, and as a compensatory measure, the GFR is increased.
E) All of these.

Question 61

Which of the following symptoms is not associated with alkalosis?

A) disorientation and comatose state
B) tingling "pins and needles" sensations
C) muscle twitches and muscle spasms
D) extreme nervousness
E) convulsions

Question 62

Which statement is correct?

A) Respiratory rate and depth decrease as a compensatory measure to combat metabolic acidosis.
B) The respiratory system can compensate completely for uremic acidosis.
C) Metabolic alkalosis inhibits (depresses) the respiratory center.
D) The respiratory responses to acid-base imbalances represent the first line of defense against changes in pH of the body fluids.
E) The respiratory system responds to changes in [H⁺] only if the kidneys are unable to cope with the change.

Question 63

When the concentration of H⁺ increases above normal, for compensation the response is a(n):

A) decreased excretion of H⁺ in the urine
B) increased concentration of H⁺ in the plasma
C) increased reabsorption of all filtered bicarbonate ions
D) increased secretion of aldosterone from the posterior pituitary
E) synthesis of H⁺ by acid dissociation

Question 64

Which statement is incorrect?

A) A chemical buffer system consists of a pair of substances involved in a reversible reaction, one that can yield free H⁺ and one that can bind with free H⁺.
B) A chemical buffer system minimizes changes in the pH of a solution when an acid or base is added to or removed from the solution.
C) Buffers respond to pH changes in about three minutes, but then can be very effective in preventing dramatic pH changes.
D) A buffer system cannot actually eliminate hydrogen ions from the body.
E) Buffer systems act according to the law of mass action.

Question 65

The kidney tubular cells secrete NH₃

A) when the urinary pH becomes too high
B) when the body is in a state of alkalosis
C) to buffer the acid phosphate excreted in the urine
D) when there is excess NH₃ in the body fluid
E) to enable further renal secretion of H⁺

Question 66

A patient with lung congestion would

A) have higher levels of carbonic acid in the blood
B) have a greater respiratory rate
C) be making use of chemical buffers to a greater extent
D) all of these
E) none of these

Question 67

Which of the following symptoms is associated with acidosis?

A) extreme nervousness
B) disorientation and comatose state
C) tingling, "pins and needles" sensations
D) muscle twitches and muscle spasms
E) convulsions

Question 68

Chemical buffer systems

A) respond in one to three minutes to changes in hydrogen ion concentration
B) stimulate the respiratory center when acidosis is present
C) promote H⁺ excretion by the kidneys when acidosis is present
D) are the most powerful mechanism available for regulating changes in [H⁺] within the body
E) buffers changes in acid or base levels

Question 69

Which chemical buffer system primarily buffers against carbonic acid changes?

A) bicarbonate
B) protein
C) hemoglobin
D) phosphate
E) ammonium

Question 70

Which of the following is not influenced by a change in the pH of body fluids?

A) phosphate excretion
B) enzyme activity
C) potassium excretion
D) protein shape and activity
E) nerve and muscle excitability

Question 71

H⁺ generated from CO₂ at the tissue level is

A) the major source of hydrogen ion in the body
B) normally buffered in transit between the tissues and the lungs by hemoglobin
C) responsible for the fact that the pH of the venous blood is higher than the pH of the arterial blood
D) the major source of hydrogen ion in the body and normally buffered in transit between the tissues and the lungs by hemoglobin
E) all of these

Question 72

Chemical buffer systems

A) can act within a fraction of a second to buffer changes in [H⁺]
B) are the only mechanism available for regulating changes in [H⁺] within the body
C) actually eliminate acid from the body
D) can act within a fraction of a second to buffer changes in [H⁺], and actually eliminate acid from the body
E) none of these

Question 73

Normal blood pH

A) is slightly basic
B) is slightly alkaline
C) falls between 7.35 and 7.45
D) varies greatly
E) is slightly basic, and falls between 7.35 and 7.45

Question 74

Select the primary buffer system in the ECF.

A) bicarbonate/carbonic acid
B) chloride/hydrochloric acid
C) hemoglobin
D) phosphate
E) protein

Question 75

If the tubular filtrate becomes too acidic, which of the following is secreted by the tubular epithelial cells to buffer the secreted H⁺?

A) HCO₃^-
B) OH^-
C) NH₃
D) NH₄⁺
E) basic phosphate

Question 76

Which of the following is normally the major source of hydrogen ions in the body?

A) phosphoric and sulfuric acids formed during the metabolism of dietary proteins
B) lactic acid production by the muscles during exercise
C) carbonic acid generated from metabolically produced CO₂
D) natural acids found in foods, such as citric acid
E) fatty acids produced during fat metabolism

Question 77

If [HCO₃^-]/[CO₂] is 20/2, what is occurring?

A) uncompensated respiratory acidosis
B) uncompensated respiratory alkalosis.
C) uncompensated metabolic acidosis
D) uncompensated metabolic alkalosis
E) normal pH of body fluids

Question 78

An increased secretion of H ions in the kidney has the greatest direct effect on the tubular secretion of ____ ions.

A) calcium
B) chloride
C) phosphate
D) potassium
E) sodium

Question 79

Which statement is incorrect?

A) Respiratory rate and depth increase as a compensatory measure to combat metabolic acidosis.
B) The respiratory system can compensate completely for metabolic acidosis.
C) The respiratory responses to acid-base imbalances represent the second line of defense against changes in pH of the body fluids.
D) Metabolic alkalosis inhibits (depresses) respiration.
E) The respiratory system responds to changes in [H⁺] within one to three minutes.

Question 80

H⁺ generated at the tissue level from CO₂ is buffered in transit between the tissues and the lungs primarily by

A) hemoglobin
B) phosphate buffer system
C) H₂CO₃.HCO₃^- buffer system
D) plasma proteins
E) respiratory regulation