test bank Human Physiology: An Integrated Approach, 6e (Silverthorn) Chapter 20 Integrative Physiology II: Fluid and Electrolyte Balance

1) The primary route for water loss from the body is the ________ system.

A) respiratory

B) urinary

C) digestive

D) integumentary

E) cardiovascular

: B

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

2) The primary route for ion loss from the body is the ________ system.

A) respiratory

B) urinary

C) digestive

D) integumentary

E) cardiovascular

: B

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

3) Cell volume (and therefore cell function) in most cells is dependent upon careful regulation of

A) volume of extracellular fluid.

B) blood pressure.

C) osmolarity of extracellular fluid.

D) permeability of cell membranes.

E) resting membrane potential.

: C

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

4) The two organ systems that work together to regulate most aspects of the body's water balance are

A) digestive and respiratory.

B) urinary and respiratory.

C) cardiovascular and respiratory.

D) urinary and cardiovascular.

E) digestive and cardiovascular.

: D

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

5) Kidneys respond relatively ________ to changes in blood volume.

A) slowly

B) quickly

: A

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

6) Shrinkage of hepatocytes in the liver causes them to cause which of the following?

A) glycogen production only

B) glycogen breakdown only

C) protein synthesis only

D) both glycogen production and protein synthesis

E) both glycogen breakdown and protein synthesis

: B

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

7) Most body water is located

A) in plasma.

B) in interstitial fluid.

C) inside cells.

D) in lumens of organs open to the outside.

: C

Section Title: Fluid and Electrolyte Homeostasis

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

8) Kidneys regulate

A) water loss only.

B) water gain only.

C) both water loss and gain.

: A

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

9) When a body is dehydrated, water in the urinary bladder

A) can be returned to the circulation directly.

B) can be returned to the circulation after moving back into the kidneys.

C) will still be expelled from the body in the urine.

: C

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

10) Water reabsorption by the kidneys is a result of

A) both passive and active transport processes.

B) cotransport with ions.

C) exchange with ions.

D) osmosis.

: D

Section Title: Water Balance

Learning Outcome: 20.2

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

11) The hormone that directly controls water excretion by the kidneys is

A) ADH.

B) aldosterone.

C) epinephrine.

D) ANP.

E) angiotensin.

: A

Section Title: Water Balance

Learning Outcome: 20.2

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

12) The hormone that regulates water excretion by the kidneys

A) decreases water permeability throughout the kidney tubules.

B) increases water permeability throughout the kidney tubules.

C) only decreases water permeability in certain portions of the kidney tubules.

D) only increases water permeability in certain portions of the kidney tubules.

: D

Section Title: Water Balance

Learning Outcome: 20.2

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

13) Why do patients taking loop diuretics need to take supplemental potassium?

A) They cause active secretion of potassium in the loop of Henle.

B) They inhibit the reabsorption of potassium as well as sodium in the loop of Henle.

C) They inhibit intestinal absorption of potassium.

D) They cause active reabsorption of potassium in the distal convoluted tubule.

: B

Section Title: Water Balance

Learning Outcome: 20.4

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

14) The primary osmoreceptors are located in the

A) pons.

B) kidney.

C) stomach.

D) hypothalamus.

E) medulla.

: D

Section Title: Water Balance

Learning Outcome: 20.3

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

15) Osmoreceptors depolarize after they ________ in response to ________ plasma osmolarity.

A) shrink, decreased

B) shrink, increased

C) swell, decreased

D) swell, increased

: B

Section Title: Water Balance

Learning Outcome: 20.3

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

16) The hormone ADH

A) is secreted by the anterior pituitary gland in response to changes in blood osmolarity.

B) stimulates the kidneys to retain sodium ion.

C) stimulates water conservation at the kidneys.

D) causes the kidneys to produce a large volume of urine.

E) All of the answers are correct.

: C

Section Title: Water Balance

Learning Outcome: 20.2

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

17) When venous return is increased, stretch receptors in the atria of the heart are activated.

This results in

A) secretion of ADH.

B) inhibition of ADH secretion.

C) increased glomerular filtration.

D) decreased urine production.

E) increased thirst.

: B

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

18) When baroreceptors in the carotid and aortic bodies register increased blood pressure, this results in

A) secretion of ADH.

B) inhibition of ADH secretion.

C) increased glomerular filtration.

D) decreased urine production.

E) increased thirst.

: B

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

19) Why is sodium actively reabsorbed in the nephron?

A) to decrease osmolarity inside the nephron

B) to make urine less concentrated

C) to increase passive reabsorption of water

D) to decrease blood pressure

: C

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

20) Juxtaglomerular cells in the nephron secrete

A) angiotensinogen.

B) angiotensin I.

C) aldosterone.

D) renin.

E) angiotensin converting enzyme.

: D

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.7

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

21) ACE converts

A) renin to angiotensinogen.

B) angiotensinogen to angiotensin I.

C) angiotensin I to angiotensin II.

D) angiotensin II to aldosterone.

E) renin to aldosterone.

: C

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

22) Stimuli for the activation of the RAAS pathway include

A) low blood pressure in arterioles in the nephron only.

B) a decrease in fluid flow through the distal tubule only.

C) high blood pressure in the renal artery only.

D) low blood pressure in arterioles in the nephron and a decrease in fluid flow through the distal tubule.

E) low blood pressure in arterioles in the nephron, a decrease in fluid flow through the distal tubule, and high blood pressure in the renal artery.

: D

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

23) Angiotensin II

A) stimulates thirst only.

B) causes widespread vasoconstriction throughout the body only.

C) causes the synthesis and release of aldosterone from the adrenal cortex.

D) stimulates thirst and causes widespread vasoconstriction throughout the body.

E) stimulates thirst, causes widespread vasoconstriction throughout the body, and causes the synthesis and release of aldosterone from the adrenal cortex.

: E

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

24) Which of the following is NOT true about angiotensin II?

A) increases cardiac output

B) activates parasympathetic output

C) is a potent vasoconstrictor

D) elevates blood pressure

E) stimulates thirst

: B

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

25) Drugs that treat hypertension by preventing Angiotensin I from becoming Angiotensin II are called

A) ACE inhibitors.

B) beta blockers.

C) calcium channel blockers.

D) diuretics.

: A

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

26) Aldosterone

A) is secreted in response to elevated levels of sodium in the blood.

B) promotes sodium retention in the kidneys.

C) helps decrease blood volume.

D) increases the concentration of sodium in urine.

E) functions in pH regulation.

: B

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

27) Atrial natriuretic peptide

A) increases the GFR.

B) inhibits the release of renin.

C) stimulates the release of renin.

D) increases the GFR and inhibits the release of renin.

E) increases the GFR and stimulates the release of renin.

: D

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.9

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

28) An increase in plasma potassium levels is properly called

A) hypernatremia.

B) hyperpotassemia.

C) hyperpotasseplasmia.

D) hyperkalemia.

E) hypercalcemia.

: D

Section Title: Potassium Balance

Learning Outcome: 20.10

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

29) Excess potassium ions are eliminated from the body by the

A) sweat glands.

B) kidneys.

C) liver.

D) digestive system.

E) spleen.

: B

Section Title: Potassium Balance

Learning Outcome: 20.10

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

30) Thirst is

A) controlled by centers in the hypothalamus.

B) triggered by increased osmolarity.

C) relieved only when plasma osmolarity is decreased.

D) controlled by centers in the hypothalamus and triggered by increased osmolarity.

E) controlled by centers in the hypothalamus, triggered by increased osmolarity, and relieved only when plasma osmolarity is decreased.

: D

Section Title: Behavioral Mechanisms in Salt and Water Balance

Learning Outcome: 20.11

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

31) A hormone that helps to regulate the sodium ion concentration of the blood is

A) cortisol.

B) parathormone.

C) thymosin.

D) somatotropin.

E) aldosterone.

: E

Section Title: Behavioral Mechanisms in Salt and Water Balance

Learning Outcome: 20.11

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

32) Which of the following statements concerning the hormone atrial natriuretic peptide is FALSE?

A) Atrial natriuretic peptide is produced by cells in the heart.

B) Atrial natriuretic peptide promotes sodium loss at the kidneys.

C) Atrial natriuretic peptide reduces the sensation of thirst.

D) Atrial natriuretic peptide suppresses ADH secretion.

E) Atrial natriuretic peptide increases aldosterone secretion.

: E

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.9

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

33) The enzyme renin is responsible for the activation of

A) angiotensin.

B) cortisol.

C) erythropoietin.

D) atrial natriuretic peptide.

E) adrenaline.

: A

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

34) Angiotensin I is converted to angiotensin II by enzymes primarily located in the

A) kidneys.

B) liver.

C) heart.

D) lungs.

E) blood vessels.

: E

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

35) The osmolarity in the deepest part of the loop of Henle is ________ mOsM.

A) 1200

B) 100

C) 300

D) 900

E) None of these answers are correct.

: A

Section Title: Water Balance

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

36) Decreased ECF volume causes

A) sympathetic output from the cardiovascular control center to increase.

B) parasympathetic output from the cardiovascular control center to increase.

C) the force of ventricular contraction to decrease.

D) arteriolar vasodilation.

E) sympathetic output from the cardiovascular control center to increase and arteriolar vasodilation.

: A

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

37) Symptoms of low plasma pH may include

A) CNS depression.

B) confusion and disorientation.

C) numbness, tingling, or muscle twitches.

D) CNS depression and confusion and disorientation.

E) CNS depression; confusion and disorientation; and numbness, tingling, or muscle twitches.

: D

Section Title: Acid-Base Balance

Learning Outcome: 20.14

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

38) The most important factor affecting the pH of plasma is the concentration of

A) lactic acid.

B) ketone bodies.

C) organic acids.

D) carbon dioxide.

E) hydrochloric acid.

: D

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

39) The primary role of the carbonic acid-bicarbonate buffer system is

A) to buffer stomach acid.

B) to buffer carbonic acid formed by carbon dioxide.

C) the prevention of pH changes caused by organic and fixed acids.

D) to buffer the urine.

E) to increase the amount of carbonic acid during ventilation.

: C

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

40) As a result of respiratory alkalosis,

A) the respiratory rate increases.

B) the tidal volume increases.

C) the kidneys conserve bicarbonate.

D) the kidneys secrete fewer hydrogen ions.

E) the body retains less carbon dioxide.

: E

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

41) Prolonged vomiting of the stomach's contents can result in

A) respiratory acidosis.

B) respiratory alkalosis.

C) metabolic acidosis.

D) metabolic alkalosis.

E) None of the answers are correct.

: D

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

42) A person who suffers from emphysema will exhibit signs of

A) respiratory acidosis.

B) respiratory alkalosis.

C) metabolic acidosis.

D) metabolic alkalosis.

E) None of the answers are correct.

: A

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

43) A person who suffers from hyperventilation will exhibit signs of

A) respiratory acidosis.

B) respiratory alkalosis.

C) metabolic acidosis.

D) metabolic alkalosis.

E) None of the answers are correct.

: B

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

44) The principal ions in the ECF are ________.

: sodium, chloride, and bicarbonate

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

45) A(n) ________ consists of a combination of a weak acid and its dissociation products.

: buffer system

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

46) The normal pH range for most body fluids is ________.

: 7.35 to 7.45

Section Title: Acid-Base Balance

Learning Outcome: 20.14

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Knowledge)

47) When the pH rises above 7.45, a state of ________ exists.

: alkalosis

Section Title: Acid-Base Balance

Learning Outcome: 20.14

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

48) Abnormal fat and amino acid metabolism may lead to the condition called ________.

: ketoacidosis

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

49) The enzyme that catalyzes the conversion of H2O and CO2 to H2CO3 is called ________.

: carbonic anhydrase

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

50) Removal of excess water in urine is known as ________.

: diuresis

Section Title: Water Balance

Learning Outcome: 20.1

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

51) The high ________ osmolarity allows urine to be concentrated.

: medullary interstitial

Section Title: Water Balance

Learning Outcome: 20.4

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

52) AQP2 water pores are added to the cell membrane by ________ and withdrawn by ________ in a process known as ________.

: exocytosis, endocytosis, membrane recycling

Section Title: Water Balance

Learning Outcome: 20.2

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

53) The anatomical arrangement of the kidney that allows transfer of solutes from one blood vessel to another is called the ________.

: countercurrent exchange system

Section Title: Water Balance

Learning Outcome: 20.4

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

54) Paracrine feedback from the ________ in the distal tubule to the granular cells stimulates release of ________.

: macula densa, renin

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

55) The ________ cells of the distal nephron are interspersed among the principal cells and contribute to acid-base regulation.

: intercalated

Section Title: Acid-Base Balance

Learning Outcome: 20.17

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

56) How do kidneys alter urine concentration?

: Kidneys alter urine concentration by varying the amounts of water and sodium reabsorbed in the distal nephron.

Section Title: Water Balance

Learning Outcome: 20.12

: Level I: Reviewing Facts and Terms (Bloom's Taxonomy: Comprehension)

57) A rise in angiotensin II levels would result in

A) elevated blood pressure.

B) increased retention of sodium ions at the kidney.

C) increased water retention.

D) increased blood volume.

E) all of these effects.

: E

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

58) The RAAS pathway begins with

A) secretion of angiotensin converting enzyme.

B) secretion of the enzyme renin.

C) secretion of angiotensinogen.

D) secretion of aldosterone.

E) secretion of antidiuretic hormone.

: B

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

59) Renal tubule cells in the kidney medulla are constantly exposed to high extracellular osmolarity. How do they maintain normal cell volume?

A) They synthesize organic solutes as needed to match the osmolarity.

B) They synthesize water molecules through increased metabolism to offset volume loss.

C) They maintain a water-impermeable membrane.

D) They add or remove aquaporins as needed.

: A

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.12

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

60) When the pH of body fluids begins to fall, proteins will

A) release a hydrogen from the carboxyl group.

B) release a hydrogen from the amino group.

C) bind a hydrogen at the carboxyl group.

D) bind a hydrogen at the amino group.

E) cause none of these actions.

: D

Section Title: Acid-Base Balance

Learning Outcome: 20.14

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

61) When the pH of the extracellular fluid declines,

A) the kidneys excrete more sodium ions.

B) the kidneys excrete more bicarbonate ions.

C) the kidneys reabsorb more potassium ions.

D) the pH of the urine increases.

E) the kidneys reabsorb less water.

: C

Section Title: Acid-Base Balance

Learning Outcome: 20.17

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

62) Two hours before major surgery is to begin, the patient experiences "jitters," an elevated heart rate and blood pressure, increased rate of breathing, cold sweats, and an urge to urinate. These symptoms are the result of

A) sympathetic activation.

B) decreased levels of epinephrine in the blood.

C) decreased activity of sympathetic centers in the hypothalamus.

D) increased parasympathetic activity.

E) all of these mechanisms.

: A

Section Title: Integrated Control of Volume and Osmolarity

Learning Outcome: 20.1

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

63) Dan has been lost in the desert for two days with very little water. As a result, you would expect to observe

A) elevated ADH levels.

B) decreased blood osmolarity.

C) normal urine production.

D) increased blood volume.

E) cells enlarged with fluid.

: A

Section Title: Water Balance

Learning Outcome: 20.1

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

64) What effect would a decrease in pH have on the amount of potassium ion in the urine?

A) an increase in the amount of potassium in the urine

B) a decrease in the amount of potassium in the urine

C) no effect on the amount of potassium in the urine

: B

Section Title: Potassium Balance

Learning Outcome: 20.10

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

65) In response to a rapid increase of organic acid in the body, you would expect to observe

A) increased alveolar ventilation only.

B) decreased blood pressure only.

C) decreased heart rate only.

D) decreased blood pH only.

E) increased alveolar ventilation and decreased blood pH.

: E

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

66) Dehydration may cause some ions to become concentrated. If a person was suffering from severe hyperkalemia, you would expect

A) the potassium ion concentration of the interstitial fluid to be less than normal.

B) the membrane potential of nerves and muscles to be more negative.

C) the skeletal muscles to be unresponsive and cardiac arrest could occur.

D) muscle weakness and increased strength of twitch contractions.

E) All of the answers are correct.

: C

Section Title: Potassium Balance

Learning Outcome: 20.10

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

67) Draw a map that shows the renal compensation for acidosis. Draw another map for alkalosis.

: Figure 20.17 shows compensations for both acidosis and alkalosis.

Section Title: Acid-Base Balance

Learning Outcome: 20.17

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

68) Diagram the reactions and interactions of the renin-angiotensin-aldosterone pathway. What condition is the primary stimulus for its activation?

: Figure 20.10 diagrams these interactions. The primary stimulus is low blood pressure, detected in several ways.

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

69) Water gain during a day comes from either ________ or ________. How is water lost during a day?

: food, drink; metabolism

Also see Figure 20.2 in the chapter.

Section Title: Water Balance

Learning Outcome: 20.11

: Level II: Reviewing Concepts (Bloom's Taxonomy: Comprehension)

70) What three stimuli control vasopressin secretion? The most potent stimulus for vasopressin release is ________.

:

1. plasma osmolarity

2. blood volume

3. blood pressure; an increase in plasma osmolarity

Section Title: Water Balance

Learning Outcome: 20.2

: Level II: Reviewing Concepts (Bloom's Taxonomy: Application)

71) The cellular mechanisms for renal handling of H+ and HCO3- involve several membrane transporters; name three.

: Possible answers include:

1. apical Na+-H+ exchanger

2. basolateral Na+- HCO3- symport

3. H+- ATPase

4. H+- K+- ATPase

5. Na+- NH4+ antiport

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level II: Reviewing Concepts (Bloom's Taxonomy: Application)

72) What are the two ways of bicarbonate reabsorption in the proximal tubule?

:

1. convert HCO3- into carbon dioxide, then back into HCO3-

2. through the metabolism of glutamine (see Fig. 20.17)

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level II: Reviewing Concepts (Bloom's Taxonomy: Application)

73) "Water, water, every where, nor any drop to drink" is a phrase from the Rime of the Ancient Mariner by Samuel Taylor Coleridge. This poem describes an ocean ship unable to sail to land and running out of its supply of fresh water; sailors have long known that drinking seawater cannot prevent death from dehydration. What would result if the sailors attempted to alleviate their dehydration by drinking seawater? Justify your answer by describing kidney physiology. Why wouldn't reflexes, in response to dehydration, fully compensate? What does this illustrate about the force allowing kidneys to retain water under more normal conditions?

: The osmolarity of seawater is higher than that of the kidney medulla, thus the osmotic gradient that normally allows net reabsorption of water does not exist. Seawater osmolarity is largely a result of permeant ions such as sodium and chloride, so ingested seawater raises plasma osmolarity when it is absorbed. When the kidneys form a filtrate of this high-osmolarity solution, the descending limb fails to reabsorb water because the kidney medulla has a lower osmolarity than the filtrate (opposite of normal), along its entire length, and in fact the medulla would lose water as it moved into the descending limb. While ions would be reabsorbed by the ascending limb as usual, it is not enough to drive sufficient water reabsorption. Reflexes such as secretion of water-preserving hormones are ineffective because, ultimately, water reabsorption depends only on osmosis, and the normal osmotic gradient has been disrupted.

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.12

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

74) What are oropharynx receptors, which hormone do they suppress, and how is it known that they exist? If a person stranded on a desert island drank seawater to try to quench his thirst, how would this affect the oropharynx receptors?

: Oropharynx receptors inhibit the sense of thirst when they come in contact with cool water. They also inhibit secretion of vasopressin (ADH). They have not been identified anatomically, but presence of even a small amount of cold water in the throat is known to satisfy thirst even if the water is not absorbed and thus does not actually alleviate dehydration. Presence of receptors that inhibit the thirst sensation are the best guess as to how this works. Presumably drinking seawater would temporarily reduce the sense of thirst by the same proposed mechanism.

Section Title: Behavioral Mechanisms in Salt and Water Balance

Learning Outcome: 20.11

: Level III: Problem Solving (Bloom's Taxonomy: Application)

75) "Glucose, glucose, every where, nor any speck to utilize" is a phrase made up by one of the authors working on this test question. Similar to the irony of not being able to prevent dehydration by drinking seawater, people with untreated diabetes mellitus are unable to prevent starvation despite the large amount of glucose surrounding their cells; as if that isn't bad enough, dehydration is also a problem. Explain why there is glucose in the urine of such people, why glucose is not present in the urine of normal people, and why diabetics become dehydrated.

: Glucose is in the urine simply because the plasma concentration exceeds the number of glucose transporters in the kidney tubules, because plasma glucose is unusually high. Normal individuals are able to reabsorb all the glucose in the filtrate because plasma glucose concentrations are normally low (normal body cells absorb glucose, diabetic cells do not). Glucose in the filtrate raises the osmolarity of the filtrate, which decreases the relative osmotic gradient for reabsorption of water; thus more water is lost in the urine leading to dehydration.

Section Title: Water Balance

Learning Outcome: 20.12

: Level III: Problem Solving (Bloom's Taxonomy: Application)

76) Devising new food recipes is more successful when the chefs understand basic food chemistry. For example, to create a new cake recipe, one must understand the role of both acids and bases in leavening (rising, or trapping of tiny gas bubbles as dough is baking, to provide the characteristic texture). The principle is to incorporate baking soda (NaHCO3) into an acidic batter, causing a chemical reaction resulting in gas production. Looking at the chemical formula, what gas do you think is formed? Summarize the chemical reaction that occurs in a cake batter that contains NaHCO3 and vinegar or acetic acid (produces acetate when ionized: CH3COO- + H+). What would happen to your cake if you didn't use enough baking soda? What would happen if you forgot to acidify your batter with vinegar or a similar food acid?

: CO2 gas is formed. NaHCO3 + CH3COO- + H+ → Na+ + CH3COO- + CO2 + H2O.

Less gas would be produced, so the cake wouldn't rise normally. The chemical reaction would not occur, so the cake wouldn't rise.

Section Title: Acid-Base Balance

Learning Outcome: 20.15

: Level III: Problem Solving (Bloom's Taxonomy: Application)

77) Fred suffers from chronic emphysema. Blood tests show that his pH is normal but his bicarbonate levels are elevated significantly. How can this be?

: As long as the ratio of bicarbonate ion to carbonic acid is 20:1, the pH of body fluids will remain normal. Since Fred's condition is chronic (long term) his body has compensated for the excess carbonic acid (the result of hypercapnea due to poor ventilation) by increasing the amount of bicarbonate to match the elevated level of acid. This process involves the kidneys where some of the excess carbon dioxide is converted into carbonic acid and the carbonic acid is allowed to dissociate. The hydrogen ions are secreted and the newly formed bicarbonate is conserved to maintain a proper buffering capacity.

Section Title: Acid-Base Balance

Learning Outcome: 20.16

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

78) Mary, a nursing student, has been caring for burn patients. She notices that they consistently show elevated levels of potassium in their urine and wonders why. What would you tell her?

: When tissues are burned, cells are destroyed and the contents of their cytoplasm leak into the interstitial fluid and then move into the plasma. Since potassium ion is normally found within the cell, damage to a large number of cells would release relatively large amounts of potassium into the blood. The elevated potassium levels would stimulate the cells of the adrenal cortex that produce aldosterone. The elevated levels of aldosterone would promote sodium retention and potassium secretion by the kidneys, thus accounting for the elevated levels of potassium in the patient's urine.

Section Title: Potassium Balance

Learning Outcome: 20.10

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

79) Mr. Gregory comes to the doctor with high blood pressure. Tests show that he also has elevated levels of renin in his blood and atherosclerotic plaques that have nearly blocked blood flow through his renal arteries. Mr. Gregory is puzzled. Explain to him how decreased blood flow in his renal arteries could cause renin secretion to increase. Map the pathways through which elevated renin causes high blood pressure for Mr. Gregory.

: Atherosclerotic plaques block blood flow, which decreases GFR and decreases pressure in the afferent arteriole. These are both stimuli for renin release. Renin secretion starts a cascade that produces angiotensin II, a vasoconstrictor. Vasoconstriction increases blood pressure, and the medullary control center responds to Ag II by also increasing ADH, aldosterone secretion, and thirst, collectively increasing blood pressure even further.

Section Title: Sodium Balance and ECF Volume

Learning Outcome: 20.8

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

80) How does decreased blood pressure affect the following: granular cells, glomerulus, cardiovascular control center, hypothalamus? Indicate if decreased blood pressure directly affects the organ or tissue above or acts through a reflex pathway. If it acts through a reflex pathway, name the reflex.

: See Table 20.1 in the chapter.

Section Title: Integrated Control of Volume and Osmolarity

Learning Outcome: 20.7

: Level III: Problem Solving (Bloom's Taxonomy: Application)

81) Gossip, an undergraduate, has normal PCO2 levels, high H+ levels, low pH and bicarbonate levels. What type of disturbance is Gossip suffering from and what might cause this? If his PCO2 were elevated, would your answer change? Explain.

: Gossip is likely suffering from metabolic acidosis, since his PCO2 is normal. If his PCO2 was elevated, then he would likely be suffering from respiratory acidosis. Metabolic acidosis may be caused by ingestion of methanol, aspirin, and ethylene glycol. Respiratory acidosis can be caused by drugs or alcohol depression, increased resistance in asthma, impaired gas exchange in fibrosis or severe pneumonia, and muscle weakness in muscular dystrophy and other muscle diseases. The most common cause is chronic obstructive pulmonary disease.

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

82) Diabetes mellitus produces many homeostatic imbalances, including acidosis. The pH imbalance is due to ketoacidosis, which results from excessive accumulation of by-products of fat metabolism, as the body cannot meet energy needs from carbohydrate metabolism. Sally is a teenaged diabetic who sometimes rebels by not taking her insulin. Her mother takes her to the hospital because her breathing has become deep and gasping. Explain Sally's breathing pattern. What other compensatory responses may occur, and would they occur earlier or later than the respiratory response?

: Sally's respiratory system is responding to her ketoacidosis. By hyperventilating, she removes more CO2 from her blood, which shifts the carbonic acid equation to the right, removing free H+ and raising pH. Chemical buffering in the blood occurs immediately after the initial pH disturbance, as this is an ongoing process. The kidneys buffer more slowly, so they are effective later.

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level III: Problem Solving (Bloom's Taxonomy: Analysis)

83) Diabetes mellitus produces many homeostatic imbalances, including acidosis. The pH imbalance is due to ketoacidosis, which results from excessive accumulation of by-products of fat metabolism, as the body cannot meet energy needs from carbohydrate metabolism. Sally is a teenaged diabetic who sometimes rebels by not taking her insulin. Her body is beginning to develop ketoacidosis as a result. Create a chart to indicate and explain how her blood pH, HCO3-, and PCO2 react, by indicating "increase," "decrease," or "no change."

1. ketoacidosis has just developed

2. respiratory compensation occurs

3. renal compensation occurs

:

1. pH decreases by definition, HCO3- decreases as the carbonic acid reaction shifts to the right, PCO2 is unchanged because the excess is expelled by the lungs due to the higher gradient.

2. pH increases and HCO3- decreases as exhaled CO2 drives the carbonic acid reaction to the right, and PCO2 decreases as it is exhaled.

3. pH increases as H+ is excreted, HCO3- increases as it is reabsorbed, and increases as respiration returns to normal.

Section Title: Acid-Base Balance

Learning Outcome: 20.18

: Level IV: Quantitative Problems (Bloom's Taxonomy: Application)

84) The graph below has had its labels removed. One axis is plasma osmolarity. The other axis is EITHER plasma vasopressin concentration OR plasma aldosterone concentration. Write the correct label on each axis of the graph, and explain how you came to that conclusion.

: The dependent variable is typically used for the y-axis, and the independent variable for the x-axis. Plasma osmolarity is the independent variable, and it regulates the secretion of hormones. As osmolarity increases, vasopressin secretion increases to promote water retention, but aldosterone secretion is inhibited to promote sodium loss. Therefore vasopressin concentration is the correct label for the y-axis. See Figure 20.6 in the chapter.

Section Title: Water Balance

Learning Outcome: 20.3

: Level IV: Quantitative Problems (Bloom's Taxonomy: Application)