Deck 19: The Urinary System: Fluid and Electrolyte Balance

Question 1

The regulation of acid -base balance in the kidneys occurs primarily through the unique action of which cells in the distal tubules and collecting ducts?

A) mesangial cells
B) granular cells
C) principal cells
D) intercalated cells
E) podocytes

Answer 1

D

Question 2

Plasma can gain solutes and/or water from which of the following?

A) gastrointestinal tract only
B) renal tubules only
C) bone only
D) both the gastrointestinal tract and bone
E) both the gastrointestinal tract and renal tubules

Answer 2

D

Question 3

What solute is primarily responsible for producing the osmotic gradient that drives water reabsorption?

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

Answer 3

C

Question 4

Which of the following is a source of water input?

A) digestive tract only
B) renal tubules only
C) metabolism only
D) both digestive tract and metabolism
E) both the digestive tract and renal tubules

Question 5

A substance is in negative balance when

A) it enters plasma at a greater rate than it exits plasma.
B) its production by cells is increased.
C) it exits plasma at a greater rate than it enters plasma.
D) its usage by cells is decreased.
E) it enters plasma at the same rate it exits plasma.

Question 6

A student in your physiology lab is thirsty and decides to sneak a drink of deionized or distilled water. The student drinks a fairly large quantity of this water in a short period of time. What will happen to the student's cells?

A) Water is water, so it will not do anything to the student's cells.
B) It will cause the student's cells to swell.
C) It will cause the student's cells to shrink.
D) It is an isotonic solution, so water will enter and leave cells at the same rate.
E) It will make the cells hypovolemic.

Question 7

The regulation of water and ion excretion occurs primarily within the

A) proximal tubules only.
B) late distal tubules only.
C) collecting ducts only.
D) both proximal tubules and late distal tubules.
E) both collecting ducts and late distal tubules.

Question 8

If a person is normovolemic and consumes a large quantity of a hyperosmotic solution, it will

A) cause cells to swell due to an increase in the osmolarity of extracellular fluid.
B) cause cells to shrink due to an increase in the osmolarity of extracellular fluid.
C) cause cells to shrink due to a decrease in the osmolarity of extracellular fluid .
D) cause cells to swell due to a decrease in the osmolarity of extracellular fluid.
E) have no effect on cell osmolarity and thereby cell size.

Question 9

Kidneys compensate for changes in plasma volume and osmolarity by adjusting the rate of water

A) reabsorption only.
B) secretion only.
C) resorption only.
D) reabsorption and secretion.
E) secretion and resorption.

Question 10

A greater plasma volume than normal is called

A) normovolemia.
B) equilibrium.
C) fluid balance.
D) hypervolemia.
E) hypovolemia.

Question 11

A substance is in positive balance when

A) its usage by cells is increased.
B) it exits plasma at a greater rate than it enters plasma.
C) it enters plasma at the same rate it exits plasma.
D) its production by cells is decreased.
E) it enters plasma at a greater rate than it exits plasma.

Question 12

What regulates the rate of water loss?

A) kidney
B) cardiovascular system
C) digestive tract
D) skin
E) lungs

Question 13

The regulation of sodium and water balance in the kidneys occurs primarily through the unique action of which cells in the distal tubules and collecting ducts?

A) mesangial cells
B) intercalated cells
C) granular cells
D) podocytes
E) principal cells

Question 14

Seawater has an osmolarity of around 1000 mOsm, mostly from dissolved sodium. Given what you know about the osmolarity in most of the cells in the body, why is it dangerous to drink seawater?

A) In the digestive system, the seawater would draw more water out of the bloodstream than would be absorbed, leading to severe dehydration.
B) In the nervous system, the additional extracellular sodium concentration would slow down the normal flow of sodium ions used to generate action potentials.
C) In the cardiovascular system, the higher sodium levels would decrease the pressure in the arteries making it more difficult to get blood to the systemic capillaries.
D) In membrane transport, the increased sodium concentration would slow down secondary active transport of glucose into cells.
E) In the renal system, the osmolarity of the medulla of the kidney would become even more concentrated.

Question 15

Which of the following is NOT a mechanism of dissipating heat during exercise?

A) convection
B) evaporation
C) secretion of ADH
D) radiation
E) conduction

Question 16

Which of the following accurately describes the thick ascending limb of the loop of Henle?

A) permeable to water and contains Na⁺/K⁺/Cl ^-cotransporters
B) impermeable to water and does NOT contain Na⁺/K⁺/Cl ^-cotransporters
C) permeable to water and does NOT contain Na⁺/K⁺/Cl ^- cotransporters
D) impermeable to water and contains Na⁺/K⁺/Cl ^-cotransporters
E) permeable to water in the presence of specific hormones

Question 17

Which of the following conditions is NOT indicative of a decrease in plasma osmolarity?

A) seizure
B) headache
C) nausea
D) neural hyperexcitability
E) confusion

Question 18

Fluid and electrolyte balance occur when

A) the charges are neutral and happen to be in an aqueous solution.
B) the amount of solute in the plasma is the same as the amount in the interstitial fluid.
C) solutes and water exit the plasma at a greater rate than it enters.
D) solutes and water enter the plasma at a greater rate than it exits.
E) solutes and water enter and exit the plasma at the same rate.

Question 19

What is the force that moves water out of the distal tubules and collecting ducts?

A) the active transport of water
B) an alteration in temperature
C) the passive regulated movement through Na⁺/H₂O transporter
D) an osmotic gradient
E) the passive unregulated movement along the paracellular pathway

Question 20

Under which of the following conditions do cell volumes not change and the osmolarity in both extracellular and intracellular fluids remain the same?

A) hypervolemia
B) osmotic equilibrium
C) hypovolemia
D) hypertonicity
E) hypotonicity

Question 21

What is the strongest stimulus for the release of antidiuretic hormone from the posterior pituitary?

A) decrease in sodium content of the blood
B) decrease in blood pressure
C) decrease in plasma osmolarity
D) increase in blood pressure
E) increase in plasma osmolarity

Question 22

A person must void what volume of urine per day?

A) 0 mL
B) 15 mL
C) 120 mL
D) 440 mL
E) 1200 mL

Question 23

Which of the following diseases is associated with decreased responsiveness of the renal tubules to ADH?

A) diabetes mellitus type 1
B) diabetes mellitus type 2
C) diabetic nephropathy
D) nephrogenic diabetes insipidus
E) central diabetes insipidus

Question 24

Which of the following statements on sodium movement in the renal tubules is TRUE?

A) Sodium is actively transported across the basolateral membrane of both the proximal and distal tubule.
B) Sodium channels are located on the basolateral membrane of principal cells.
C) Sodium is actively secreted from the proximal tubule.
D) Sodium is actively secreted from the collecting duct.
E) Sodium reabsorption follows water reabsorption in all segments of the renal tubules.

Question 25

At high concentrations of antidiuretic hormone, the extent of water reabsorption in the collecting ducts is _ , causing urine output to _ .

A) high : decrease
B) high : increase
C) low : decrease
D) low : increase
E) unaffected : remain unchanged

Question 26

Antidiuretic hormone binds to receptors on cells in the collecting ducts and distal tubules where it .

A) granular : causes vesicles with aquaporin -2 to insert into the apical membrane
B) principal : causes insertion of aquaporin -2 into the apical membrane
C) intercalated : causes vesicles with aquaporin -2 to insert into the basolateral membrane
D) intercalated : causes vesicles with aquaporin -3 to insert into the apical membrane
E) principal : causes vesicle with aquaporin -3 to insert into the apical membrane

Question 27

In the renal tubules, where is the Na⁺/K⁺ pump located?

A) in the apical membrane of the descending limb of the loop of Henle
B) in the basolateral membrane of the proximal tubules
C) in both the apical and basolateral membranes of principal cells
D) in the apical membrane of the collecting ducts
E) in both the apical and basolateral membranes of intercalated cells

Question 28

In the early portion of the collecting duct (in cortical interstitial fluid), an increase in water permeability will result in a(n)

A) transport of sodium out of the tubule.
B) efflux of urea from the tubule.
C) decrease in filtrate volume.
D) movement of water into the duct.
E) increase in filtrate volume.

Question 29

Which of the following conditions would be associated with hypernatremia?

A) increased plasma potassium
B) increased plasma sodium
C) decreased plasma osmolarity
D) decreased plasma volume
E) hypotension

Question 30

Which of the following correctly describes water movement across the epithelial cells lining the collecting duct?

A) Water can permeate the phospholipid bilayer only in the presence of aldosterone.
B) Water can permeate the apical membrane through aquaporin -2 and the basolateral membrane through aquaporin -3, but aquaporin -2 is only present in the presence of ADH.
C) Water can permeate the lipid bilayer at all times.
D) Water can permeate the basolateral membrane through aquaporin -2 and the apical membrane through aquaporin -3, but aquaporin -2 is only present in the presence of aldosterone.
E) Water can permeate the phospholipid bilayer only in the presence of ADH.

Question 31

If nothing else is removed from the filtrate once it reaches the late distal tubules, the urine excreted would have which of the following properties?

A) low osmolarity and low volume
B) high osmolarity and low volume
C) devoid of ions and large volume
D) low osmolarity and large volume
E) high osmolarity and large volume

Question 32

Which of the following best describes sodium movement in the proximal tubule?

A) Sodium is transported across the basolateral membrane by the Na⁺/K⁺ pump and across the apical membrane by secondary active transport.
B) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by diffusion through sodium channels.
C) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by secondary active transport.
D) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by facilitated diffusion.
E) Sodium is transported across the basolateral membrane by the Na⁺/K⁺ pump and across the apical membrane by diffusion through sodium channels.

Question 33

From where is ADH released?

A) collecting duct
B) anterior pituitary
C) posterior pituitary
D) distal tubule
E) pancreas

Question 34

In diabetes insipidus, blood levels of

A) aldosterone : potassium in the urine
B) ADH : plasma volume
C) aldosterone : sodium in the urine
D) insulin : glucose in the urine
E) ADH : urine volume

Question 35

What solute maintains the medullary interstitial fluid osmotic gradient?

A) urea
B) glucose
C) potassium ions
D) sodium ions
E) water

Question 36

Which of the following is an effect of aldosterone on principal cells?

A) decreased number of Na⁺/K⁺ pumps in the basolateral membrane
B) decreased number of open Na⁺/K⁺ channels in the basolateral membrane
C) increased number of Na⁺/K⁺ pumps in the apical membrane
D) increased number of open Na⁺/K⁺ channels in the basolateral membrane
E) increased number of open Na⁺/K⁺ channels in the apical membrane

Question 37

Which of the following best describes sodium movement in the distal tubule?

A) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by diffusion through sodium channels.
B) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by secondary active transport.
C) Sodium is transported across the apical membrane by the Na⁺/K⁺ pump and across the basolateral membrane by facilitated diffusion.
D) Sodium is transported across the basolateral membrane by the Na⁺/K⁺ pump and across the apical membrane by diffusion through sodium channels.
E) Sodium is transported across the basolateral membrane by the Na⁺/K⁺ pump and across the apical membrane by facilitated diffusion.

Question 38

The osmotic gradient in the medullary region of the kidneys is established and maintained by which of the following?

A) Na⁺/K⁺/Cl ^-cotransporters in the ascending limb of the loop of Henle
B) Na⁺/K⁺/Cl ^-cotransporters in the descending limb of the loop of Henle
C) efflux of water from the descending limb of the loop of Henle
D) efflux of water from the ascending limb of the loop of Henle
E) efflux of Na⁺ from the descending limb of the loop of Henle

Question 39

Aldosterone is released from the in response to _.

A) pancreas : increases in plasma glucose
B) adrenal cortex : increases in plasma potassium
C) adrenal medulla : decreases in plasma sodium
D) posterior pituitary : increases in plasma osmolarity
E) macula densa : increased flow of tubular fluid in the distal tubule

Question 40

In diabetes insipidus, why does polyuria occur?

A) A lack of angiotensin II decreases thirst.
B) An increase in aldosterone increases water reabsorption.
C) A lack of insulin decreases water permeability of the renal tubules.
D) Glucose transporters in the renal tubules become saturated.
E) A lack of ADH decreases water reabsorption.

Question 41

Which of the following conditions triggers the release of renin?

A) high blood pressure
B) low blood pressure
C) increased sympathetic stimulation
D) atrial stretching due to increased plasma volume
E) increased mean arterial pressure (MAP)

Question 42

What stimulates atrial natriuretic peptide release?

A) changes in the concentration of sodium in the blood of the atrium
B) renin
C) changes in the concentration of potassium in the blood of the atrium
D) distension of the atrial wall due to an increase in plasma volume
E) distension of the atrial wall due to an increase in blood pressure

Question 43

Potassium secretion is regulated by

A) atrial natriuretic peptide (ANP).
B) aldosterone.
C) parathyroid hormone (PTH).
D) angiotensin I.
E) renin.

Question 44

Which of the following is associated with actions of aldosterone on principal cells?

A) increased sodium secretion
B) decreased blood pressure
C) increased potassium secretion
D) increased calcium reabsorption
E) decreased plasma osmolarity

Question 45

Renin is released by cells of the .

A) principal : afferent arteriole
B) principal : distal tubule
C) intercalated : afferent arteriole
D) granular : afferent arteriole
E) granular : distal tubule

Question 46

The extent of potassium excretion is regulated primarily by the

A) amount secreted into the proximal tubule.
B) amount reabsorbed into the proximal tubule.
C) amount filtered by the basement membrane of the glomerular capillaries.
D) amount reabsorbed in the distal tubule.
E) amount secreted into the distal tubule.

Question 47

Exposure of the skin to sunlight converts

A) calcitriol
B) cholesterol
C) 25 -OH D₃
D) calcium
E) 7 -dehydrocholesterol

Question 48

What enzyme converts angiotensin I into angiotensin II?

A) renin
B) angiotensin converting enzyme (ACE)
C) atrial natriuretic peptide
D) carbonic anhydrase
E) mucin

Question 49

Angiotensinogen is synthesized by what organ?

A) pituitary gland
B) liver
C) kidney
D) bone marrow
E) adrenal gland

Question 50

Atrial natriuretic peptide causes which of the following effects in principal cells?

A) afferent arteriole constriction
B) decreased activity of the Na⁺/K⁺ pump in the basolateral membrane
C) efferent arteriole dilation
D) increase in glomerular filtration rate
E) decreased number of open sodium channels in the apical membrane

Question 51

A decrease in plasma calcium will initiate an increase in the release of which of the following?

A) parathyroid hormone only
B) calcitonin only
C) 1,25 -dihydroxy vitamin D₃ only
D) both parathyroid hormone and calcitonin
E) both parathyroid hormone and 1,25 -dihydroxy vitamin D₃

Question 52

Hyperkalemia refers to an excess of what?

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

Question 53

What enzyme converts angiotensinogen into angiotensin I?

A) atrial natriuretic peptide
B) angiotensin converting enzyme (ACE)
C) renin
D) mucin
E) carbonic anhydrase

Question 54

The primary function of atrial natriuretic peptide (ANP) is to

A) increase potassium secretion thereby decreasing potassium reabsorption.
B) increase sodium secretion thereby decreasing sodium reabsorption.
C) decrease potassium secretion thereby increasing potassium reabsorption.
D) increase the stretching capacity of the atria.
E) decrease sodium secretion thereby increasing sodium reabsorption.

Question 55

ACE inhibitors prevent angiotensin converting enzyme (ACE) from performing its role in the body. Which statement best describes why doctors prescribe ACE inhibitors?

A) ACE inhibitors block the production of renin in the juxtaglomerular cells in the kidneys reducing fluid volume and, therefore, blood pressure.
B) ACE inhibitors block baroreceptors and reduce sympathetic activity to the cardiovascular system, thereby reducing blood pressure.
C) ACE inhibitors reduce blood pressure by blocking the conversion of angiotensin I to angiotensin II.
D) ACE inhibitors slow down the heart rate by not allowing atrial natriuretic peptide (ANP) to be released from the heart, decreasing sodium production and, therefore, blood pressure.
E) ACE inhibitors increase blood pressure by blocking the RASS pathway.

Question 56

What form of osteoporosis would be localized to a specific bone?

A) disuse osteoporosis
B) primary osteoporosis
C) secondary osteoporosis
D) tertiary osteoporosis
E) hyperosteoporosis

Question 57

The bone can supply calcium to the plasma by what process?

A) reabsorption
B) ossification
C) resorption
D) calcification
E) filtration

Question 58

Which of the following structures is NOT involved in the regulation of plasma calcium?

A) kidneys
B) skeletal muscle
C) bone
D) skin
E) gastrointestinal tract

Question 59

Which type of cell carries out bone formation?

A) ossicles
B) osteons
C) osteoblasts
D) osteocytes
E) osteoclasts

Question 60

Angiotensin II acts directly in the hypothalamus to stimulate what?

A) an increase in thirst
B) a systemic increase in blood pressure
C) an increase in body temperature
D) the release of aldosterone
E) the release of oxytocin

Question 61

The activity of the respiratory system can increase pH by

A) a hypoventilation -induced increase in P_CO2.
B) a hyperventilation -induced decrease in P_CO2.
C) a hyperventilation -induced increase in P_CO2.
D) a hypoventilation -induced decrease in P_CO2.
E) increasing the amount of carbonic acid in the blood.

Question 62

The hydrogen ion concentration or pH of arterial blood is regulated by the combined actions of the and .

A) kidneys : buffer systems
B) lungs: buffer systems
C) kidneys : cardiovascular system
D) kidneys : lymphatic system
E) lungs : kidneys

Question 63

How does severe vomiting cause a metabolic alkalosis?

A) production of hydrogen ions
B) loss of bicarbonate
C) loss of phosphate
D) loss of hydrogen ions
E) production of bicarbonate

Question 64

How does severe diarrhea cause a metabolic acidosis?

A) loss of phosphate
B) production of bicarbonate
C) loss of bicarbonate
D) loss of hydrogen ions
E) production of hydrogen ions

Question 65

How might heavy exercise cause metabolic acidosis?

A) loss of hydrogen ions
B) production of lactic acid
C) direct production of hydrogen ions
D) loss of bicarbonate
E) loss of phosphate

Question 66

Which of the following is NOT a metabolic disturbance that can result in a metabolic acidosis?

A) high -protein diet
B) severe diarrhea
C) high -fat diet
D) excessive vomiting
E) heavy exercise

Question 67

How might a high -fat diet cause metabolic acidosis?

A) loss of phosphate
B) loss of bicarbonate
C) loss of hydrogen ions
D) breakdown of fat into fatty acids
E) direct production of hydrogen ions

Question 68

Angiotensin II and atrial natriuretic peptide are able to alter the reabsorption of water through a similar pathway that involves altered

A) integration of aquaporin -3 into the membrane.
B) sodium channel expression on the apical membrane.
C) Na⁺/K⁺ pump activity in the intercalated cells.
D) release of antidiuretic hormone (ADH).
E) Na⁺/K⁺ pump activity in the principal cells.

Question 69

Which type of cell carries out bone resorption?

A) ossicles
B) osteoblasts
C) osteoclasts
D) osteons
E) osteocytes

Question 70

How might a high -protein diet cause metabolic acidosis?

A) loss of hydrogen ions
B) direct production of hydrogen ions
C) loss of phosphate
D) loss of bicarbonate
E) production of phosphoric acid and sulfuric acid

Question 71

What is the most rapid defense against changes in blood pH?

A) cardiac compensation
B) buffering of hydrogen ions
C) hepatic compensation
D) renal compensation
E) respiratory compensation

Question 72

A person walks into the emergency room with rapid and shallow breathing and a feeling of light -headedness. A blood test shows high levels of bicarbonate ions and a pH of 7.34. What could explain these symptoms?

A) respiratory alkalosis with renal compensation
B) metabolic alkalosis with respiratory compensation
C) metabolic acidosis with respiratory compensation
D) respiratory acidosis with renal compensation
E) acidosis with no compensation

Question 73

Which of the following is NOT a response to hemorrhage?

A) decreased renin secretion
B) increased epinephrine secretion
C) increased angiotensin II production
D) increased ADH release
E) increased sympathetic activity

Question 74

The effects of antidiuretic hormone (ADH) are not restricted to regulating water movement; it also affects sodium reabsorption by

A) increasing the synthesis of Na⁺/K⁺ pumps in principal cells.
B) increasing the synthesis of sodium channels in intercalated cells.
C) decreasing the synthesis of sodium channels in intercalated cells.
D) increasing the synthesis of sodium channels in principal cells.
E) decreasing the synthesis of sodium channels in principal cells.

Question 75

Which statement BEST distinguishes metabolic acidosis from respiratory acidosis?

A) Metabolic acidosis is a disturbance in blood pH caused by exercise as opposed to hyper -or hypoventilation.
B) Metabolic acidosis occurs due to changes in P_O2 as opposed to P_CO2.
C) Metabolic acidosis occurs due to changes in bicarbonate as opposed to P_CO2.
D) Metabolic acidosis occurs due to changes in blood glucose as opposed to changes in P_O2 and P_CO2.
E) Metabolic acidosis is a disturbance in blood pH caused by something other than an abnormal P_CO2.

Question 76

The last step to synthesis of 1,25 -dihydroxy vitamin D₃ occurs in what organ?

A) brain
B) liver
C) gastrointestinal tract
D) kidney
E) skin

Question 77

During hyperventilation, why do some people detect a tingling sensation in their hands and feet?

A) an increase in carbon dioxide in blood
B) widespread release of catecholamines
C) hyperexcitability of afferent neurons
D) a decrease in carbon dioxide in blood
E) a decrease in blood flow to the distal extremities

Question 78

What hormone decreases plasma calcium levels?

A) calcitonin only
B) 1,25 -dihydroxy vitamin D_{3 only}
C) parathyroid hormone only
D) both calcitonin and 1,25 -dihydroxy vitamin D₃
E) both calcitonin and parathyroid hormone

Question 79

Which statement best describes why estrogen may contribute to osteoporosis?

A) A decrease in estrogen stimulates the production of interleukin -6 that then stimulates osteoclast activity.
B) A decrease in estrogen causes a corresponding decrease in interleukin -6 that then lowers calcium levels.
C) A decrease in estrogen stimulates an increase in osteoblast activity due to the activation of 1,25 -(OH₂) D_3.
D) A decrease in estrogen stimulates calcitonin secretion from the pituitary gland.
E) Estrogen is a steroid hormone that interferes with calcium resorption.

Question 80

The hemorrhage -induced decrease in blood flow to the kidneys will

A) increase the production of erythrocytes.
B) decrease the release of renin.
C) increase glomerular filtration rate.
D) increase the production of leukocytes.
E) increase the release of atrial natriuretic peptide.