Deck 14: The Urinary System

Question 1

Which nephron structure is especially important in the kidney's ability to produce urine of varying concentration?

A)Bowman' capsule
B)proximal tubule
C)distal tubule
D)loop of Henle
E)glomerulus

Answer 1

D

Question 2

Which of the following statements about juxtamedullary nephrons is incorrect?

A)Their glomeruli lie in the renal medulla.
B)They are important in the ability of the kidneys to concentrate urine.
C)Their loops of Henle dip deep into the medulla.
D)Their peritubular capillaries form vasa recta.
E)They are not the predominant type of nephron found in human kidneys.

Answer 2

A

Question 3

Filtrate passes through all of the following except

A)glomerular capillary pores
B)basement membrane
C)cytoplasm of podocytes
D)filtration slits
E)Bowman's capsule

Answer 3

C

Question 4

The blood that flows through the kidneys is

A)normally about 20 to 25 percent of the total cardiac output
B)all filtered through the glomeruli
C)all used to supply the renal tissue with O₂ and nutrients
D)all of the above
E)only a and b

Question 5

Which factor would reduce the net filtration pressure the most?

A)vasodilation of the afferent arteriole
B)vasoconstriction of the efferent arteriole
C)a large increase in blood colloid osmotic pressure
D)a low capsular hydrostatic pressure
E)a high glomerular hydrostatic pressure

Question 6

Vasa recta are associated with

A)afferent arterioles
B)efferent arterioles
C)cortical nephrons
D)juxtamedullary nephron
E)renal papillae

Question 7

Which of the following is not part of the nephron?

A)collecting duct
B)Bowman's capsule
C)ureter
D)descending limb
E)proximal tubule

Question 8

Which of the following is not a function of the kidneys?

A)Excreting metabolic wastes
B)Maintaining proper plasma volume
C)Secreting aldosterone to regulate sodium
D)Maintaining proper osmolarity of body fluids
E)Assisting in maintaining the proper acid-base balance of the body

Question 9

Identify the correct statement(s).

A)Bowman's capsule hydrostatic pressure opposes filtration.
B)The glomerular filtration rate is limited by a Tm.
C)All of the plasma that enters the glomerulus is filtered.
D)Both b and c
E)a, b, and c

Question 10

The glomerular filtrate

A)is a protein-free plasma
B)is formed as a result of passive forces acting across the glomerular membrane
C)does not contain foreign compounds because these substances are secreted by special transport mechanisms in the proximal tubule instead
D)is both a and b
E)is both a and c

Question 11

Which of the following is not associated with juxtamedullary nephrons?

A)Glomeruli located in medulla
B)Long loops of Henle
C)Peritubular capillaries forming vasa recta
D)Collecting duct in medulla
E)Important role in the ability of the kidneys to produce urine of varying concentration

Question 12

The glomerular capillary blood pressure in the nephron is 78 mm Hg.The Bowman's capsular hydrostatic pressure is 24 mm Hg.The colloidal osmotic pressure is 18 mm Hg.The net filtration pressure is ____ mm Hg.

A)18
B)26
C)36
D)42
E)78

Question 13

The glomerular filtration rate is

A)about 115-125 ml/min
B)about 70-75 liters/day
C)60 to 65 percent of the cardiac output
D)less than the rate of renal reabsorption
E)all of the above

Question 14

Changes in the glomerular filtration rates are accomplished through

A)autoregulation
B)myogenic activity
C)vasoactive responses in the afferent arteriole
D)all of the above
E)none of the above

Question 15

Below is a listing of nephron components and associated structures.
1)descending limb of loop of Henle
2)bowman's capsule
3)collecting tubule
4)ascending limb of loop of Henle
5)distal tubule
6)proximal tubule
Indicate the correct flow of filtrate through these structures.

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

Question 16

The peritubular capillaries

A)supply nutrients and O₂ to the tubular cells
B)take up the substances that are reabsorbed by the tubules
C)supply substances that are secreted by the tubules
D)perform all of the above
E)perform none of the above

Question 17

The functional unit of the kidney is the

A)glomerulus
B)nephron
C)medulla
D)pyramid
E)juxtaglomerular apparatus

Question 18

Which of the following is not a function of the kidneys?

A)They contribute to long-term regulation of arterial blood pressure by maintaining the proper plasma volume.
B)They act directly on the interstitial fluid to maintain constancy in its composition.
C)They excrete the metabolic waste products.
D)They assist in maintaining the proper acid-base balance of the body.
E)They secrete a hormone.

Question 19

The specialized nephron capillary bed where filtration occurs is the

A)afferent arteriole
B)efferent arteriole
C)glomerulus
D)peritubular bed
E)none of these

Question 20

The renal process whereby substances are selectively transferred from the peritubular blood into the renal tubule is

A)filtration
B)secretion
C)reabsorption
D)excretion
E)none of these

Question 21

Which of the following is reabsorbed by the proximal tubule?

A)sodium
B)amino acids
C)glucose
D)All of the above
E)None of the above

Question 22

Tubular reabsorption involves

A)active transport
B)cotransport
C)passive transport
D)countertransport
E)all of the above

Question 23

The macula densa

A)consists of specialized tubular cells in the juxtaglomerular apparatus
B)consists of specialized arteriolar smooth-muscle cells in the juxtaglomerular apparatus
C)secretes renin
D)has characteristics a and b
E)has characteristics b and c

Question 24

Which of the following factors would decrease the GFR?

A)A fall in plasma protein concentration
B)An obstruction such as a kidney stone in the tubular system, which increases Bowman's capsule hydrostatic pressure
C)Vasodilation of the afferent arterioles
D)A fall in plasma protein concentration and vasodilation of the afferent arterioles
E)None of the above

Question 25

Afferent arteriolar vasoconstriction ____ blood flow into the glomerulus, which causes the glomerular-capillary blood pressure to ____, leading to a(n) ____ in the net filtration pressure and a resultant ____ in the GFR.

A)increases; increase; increase; increase
B)decreases; decrease; decrease; decrease
C)increases; increase; decrease; decrease
D)decreases; decrease; increase; increase
E)none of these

Question 26

The Na⁺-K⁺ ATPase transport system that plays a pivotal role in tubular reabsorption is located in the

A)luminal membrane of tubular cells
B)basolateral membrane of tubular cells
C)podocytes
D)glomerular capillary membrane
E)basement membrane

Question 27

A step that is not part of transepithelial transport would be the movement of a substance

A)through the cytosol of the tubular cell
B)across the glomerular capillary wall
C)across the luminal membrane of the tubular cell
D)through the interstitial fluid
E)across the basolateral membrane of the tubular cell

Question 28

Stimulation of the macula densa cells

A)results in vasodilation of the afferent arteriole
B)results in vasoconstriction of the afferent arteriole
C)increases GFR
D)causes all of the above
E)causes only a and c

Question 29

Extrinsic control of the GFR

A)is mediated by sympathetic nervous system input to the afferent arterioles
B)is aimed at the regulation of arterial blood pressure
C)does not require a special mechanism but occurs as part of the baroreceptor reflex
D)decreases the GFR
E)has all of the above characteristics

Question 30

The myogenic mechanism

A)causes the afferent arteriole to constrict when blood pressure is too high
B)may result from stretching of vascular smooth muscle
C)is an autoregulatory mechanism
D)reduces GFR
E)has all of the above characteristics

Question 31

Into which structure does most reabsorption occur?

A)proximal tubule
B)glomerulus
C)distal tubule
D)loop of Henle
E)none of these

Question 32

Which of the following forces oppose glomerular filtration?

A)Blood colloid osmotic pressure
B)Bowman's capsule hydrostatic pressure
C)Glomerular-capillary blood pressure
D)Both a and b
E)Both b and c

Question 33

Glucose is not normally found in the urine because it is

A)not filtered out of glomerulus
B)not found in the blood
C)usually reabsorbed by renal tubule cells
D)kept in the blood
E)secreted by the tubule cells

Question 34

The proximal tubule

A)reabsorbs about 65 percent of the filtered water
B)is not the site of action of renin
C)is where glucose is reabsorbed
D)receives filtrate from Bowman's capsule
E)has all of the above characteristics

Question 35

When arterial blood pressure is elevated above normal, which of the following compensatory changes in renal function occur as a result of the baroreceptor reflex?

A)afferent arteriolar vasoconstriction
B)afferent arteriolar vasodilation
C)reduction in GFR
D)increased water reabsorption
E)Both a and d

Question 36

Glomerular filtration

A)occurs in the loop of Henle
B)is the process by which plasma water, electrolytes, and small molecules, which enter Bowman's capsule, are separated from blood cells and protein, which remain in the glomerular capillaries
C)is the process by which a substance is transported from the tubular fluid to the peritubular capillaries
D)is both a and b
E)is none of the above

Question 37

Which statement about tubular reabsorption is incorrect?

A)It refers to the movement of a substance from the tubular fluid to the peritubular capillary blood.
B)It is important for the conservation of substances important to the body, such as Na+, Cl-, glucose, and amino acids.
C)It can occur by active or passive transport mechanisms.
D)It involves the process of transepithelial transport.
E)It takes place only in the proximal tubule.

Question 38

Tubular reabsorption

A)refers to the movement of a substance from the peritubular capillary blood into the tubular fluid
B)occurs by either active or passive transport
C)involves the process of transepithelial transport
D)has b and c characteristics
E)has none of the above characteristics

Question 39

Tubular reabsorption

A)moves substance from the peritubular capillaries into the tubular fluid
B)moves substances from the tubular fluid into the peritubular capillaries
C)is considered active if any one of the five steps of transepithelial transport is active
D)has characteristics a and b
E)has characteristics b and c

Question 40

Which of the following is involved in autoregulation of the GFR?

A)A myogenic mechanism in which the afferent arteriole automatically constricts when it is stretched
B)A tubuloglomerular feedback mechanism in which vasoactive chemicals released from the juxtaglomerular apparatus bring about afferent arteriolar vasoconstriction
C)Sympathetically induced vasoconstriction of the afferent arterioles
D)Both a and b
E)None of the above

Question 41

Tubular maximum (Tm)

A)is the maximum amount of a substance that the tubular cells can actively transport within a given time period
B)is the maximum rate at which a substance is filtered at the glomerulus
C)occurs when the membrane carrier becomes saturated
D)is both a and c
E)is both b and c

Question 42

The juxtaglomerular apparatus

A)is a combination of specialized tubular and vascular cells
B)secretes renin
C)produces substances involved in the control of kidney function
D)has only two of the above characteristics
E)has characteristics a, b, and c

Question 43

Which of the following plasma constituents is not regulated by the kidneys?

A)glucose
B)Na+
C)H+
D)phosphate
E)water

Question 44

When blood volume becomes abnormally low,

A)sodium reabsorption decreases
B)more dilute urine forms
C)renin catalyzes the conversion of angiotensinogen to angiotensin I
D)aldosterone is secreted by the kidney
E)all of the above occur

Question 45

Sodium reabsorption in the distal portions of the nephron is stimulated by

A)atrial natriuretic peptide
B)vasopressin
C)angiotensin II
D)aldosterone
E)renin

Question 46

Which statement is true about Na⁺ reabsorption in the kidney?

A)It uses 80% of the energy requirement of the kidney
B)It is under control of aldosterone in the distal portions of the nephron
C)It is linked to the reabsorption of water, Cl-, glucose, amino acids, and urea
D)It requires that tubule cells expend energy
E)All of the above

Question 47

The maximum normal glucose concentration in the plasma is about ____ mg per 100 ml.

A)30
B)60
C)100
D)180
E)250

Question 48

Which statement regarding sodium reabsorption is not accurate?

A)It plays a role in glucose, amino acid, and urea reabsorption in the proximal tubule.
B)It is under hormonal control in the distal tubule.
C)In the loop of Henle, it contributes to the formation of concentrated urine.
D)Approximately 0.5% of sodium in the filtrate is reabsorbed on a daily basis.
E)Aldosterone is a key hormone involved in its reabsorption.

Question 49

Given the following data for substance X (GFR = 125 ml/min, Tm = 125 mg/min, at a plasma concentration of 200 mg/100 ml), how much of substance X is filtered, reabsorbed, and excreted?

A)200 mg/min filtered, 125 mg/min reabsorbed, 75 mg/min excreted
B)250 mg/min filtered, 125 mg/min reabsorbed, 125 mg/min excreted
C)125 mg/min filtered, 125 mg/min reabsorbed, 0 mg/min excreted
D)250 mg/min filtered, 200 mg/min reabsorbed, 50 mg/min excreted
E)none of these

Question 50

Tm is the maximum

A)rate of glomerular filtration
B)rate a substance can be reabsorbed because of saturation of the carrier molecule
C)rate of urine excretion
D)rate a substance can be cleared from the blood
E)percentage of renal blood flow that can be converted to filtrate

Question 51

Angiotensin I

A)is formed as a result of activation of angiotensinogen by renin
B)is transformed into angiotensin II as a result of converting enzyme action in the lungs
C)is the primary stimulus for the release of aldosterone from the adrenal glands
D)is both a and b
E)is both a and c

Question 52

The greatest percentage of Na⁺ reabsorption takes place in the

A)proximal tubule
B)loop of Henle
C)distal tubule
D)collecting tubule
E)renal pelvis

Question 53

Aldosterone

A)stimulates Na+ secretion in the collecting duct
B)is secreted by the juxtaglomerular apparatus
C)stimulates K+ secretion in the distal tubule
D)has all of the above characteristics
E)has characteristics a and b

Question 54

Which of the following is not attributable to atrial natriuretic peptide (ANP)?

A)It is released from the cardiac atria when the ECF volume is reduced.
B)It inhibits Na+ reabsorption in the distal parts of the nephron.
C)It inhibits renin secretion by the kidneys.
D)It inhibits aldosterone secretion by the adrenal cortex.
E)It inhibits sympathetic nervous activity to the heart and blood vessels.

Question 55

The renal threshold is the

A)maximum amount of a particular substance that can be excreted in the urine per unit of time
B)maximum amount of a particular substance that the tubular cells are capable of actively reabsorbing per unit of time
C)plasma concentration of a particular substance at which its Tm is reached and the substance first appears in the urine
D)maximum amount of waste products that can be concentrated in the urine per unit of time
E)maximum amount of water that can be osmotically absorbed across the tubules per unit of time

Question 56

Reabsorption of chloride is

A)active
B)passive
C)dependent on the amount of sodium reabsorbed
D)both a and c
E)both b and c

Question 57

The energy requirement for glucose reabsorption is used to

A)run the Na+-K+ ATPase pump
B)run the Na+-glucose co-transport carrier
C)synthesize renin, which controls glucose reabsorption
D)maintain the Tm for glucose
E)produce aldosterone-induced protein, which increases the permeability of the proximal tubular cells to glucose

Question 58

The juxtaglomerular apparatus

A)secretes renin in response to sodium depletion in the filtrate
B)is a thickened region of specialized cells at a point where the distal tubule comes into intimate contact with the afferent and efferent arterioles of the same nephron
C)secretes renin in response to a drop in afferent arteriole blood pressure
D)secretes renin in response to sympathetic impulses
E)has all of the above characteristics

Question 59

Select the major waste product of nitrogen metabolism.

A)plasma proteins
B)urea
C)glucose
D)PO4
E)amino acids

Question 60

Aldosterone secretion

A)occurs in the kidney
B)is stimulated by angiotensin II
C)is controlled by the concentration of Cl-
D)increases due to a higher-than-normal Na+ concentration in the blood
E)allows renin to become activated

Question 61

Potassium is

A)actively reabsorbed in the proximal tubule
B)actively secreted in the distal and collecting tubules
C)secreted under the control of aldosterone
D)filtered, reabsorbed, and secreted in the kidney
E)all of the above

Question 62

Which of the following usually results in an increase in aldosterone secretion?

A)An increase in plasma K+
B)A decrease in plasma K+
C)Activation of the renin-angiotensin pathway
D)Both a and c
E)Both b and c

Question 63

Urea is

A)a waste product resulting from the breakdown of protein
B)passively reabsorbed at the end of the proximal tubule down a urea concentration gradient created by the osmotic-induced reabsorption of water from the proximal tubule
C)recycled between the late portion of the collecting tubule and the long loops of Henle and this contributes to medullary hypertonicity
D)found in the blood, filtrate, and urine
E)all of the above

Question 64

When the extracellular fluid becomes too acidic, the tubular secretion of

A)no ionic substance is affected
B)hydrogen ions decreases
C)hydrogen ions increases
D)sodium ions decreases
E)sodium ions increases

Question 65

Water reabsorption

A)is under vasopressin control in the proximal tubule
B)occurs to the greatest extent in the proximal tubule
C)is under vasopressin control in the distal and collecting tubules
D)is both a and b
E)is both b and c

Question 66

Water reabsorption is under the control of vasopressin

A)along the entire length of the nephron
B)only in the loop of Henle
C)only in the distal and collecting tubules
D)only in the proximal tubule
E)only in the glomerulus

Question 67

Inulin is

A)filtered, not reabsorbed, but secreted
B)filtered, not reabsorbed, and not secreted
C)filtered, reabsorbed, and not secreted
D)filtered, reabsorbed, and secreted
E)not filtered

Question 68

Urea

A)is the waste product with the smallest molecular size in the glomerular filtrate
B)is in greater concentration at the end of the proximal tubule than in other body fluids
C)has a clearance rate greater than GFR
D)is both a and b
E)is all of the above

Question 69

Which substance is not secreted into the tubule?

A)hydrogen ions
B)potassium ions
C)organic ions
D)b and c are not secreted
E)renin

Question 70

Tubular secretion is important

A)in the renal regulation of hydrogen ion concentration
B)for the elimination of certain nonfilterable organic ions from the body
C)in the renal regulation of sodium balance
D)for reasons a and b
E)for reasons a, b, and c

Question 71

Tubular secretion

A)refers to the movement of a substance from the peritubular capillary blood into the tubular lumen
B)can occur by active or passive transport mechanisms
C)of K+ occurs in the distal and collecting tubules and is stimulated by aldosterone
D)of organic ions occurs in the proximal tubule by two distinct types of carriers
E)has all of the above characteristics

Question 72

Which statement is correct?

A)Water reabsorption is under control of vasopressin throughout the length of the nephron.
B)The ascending limb of the loop of Henle is always impermeable to water.
C)Vasopressin makes the distal and collecting tubules impermeable to water.
D)Fifteen percent of the filtered water osmotically follows the absorption of Na+ and other solutes in the proximal tubule.
E)Water reabsorption is passive in the early portions of the nephron but is active in the distal portions of the nephron.

Question 73

Tubular secretion

A)involves transepithelial transport
B)is the movement of a substance from the peritubular capillary blood into the tubular fluid
C)always occurs by active transport
D)is both a and b
E)is both b and c

Question 74

Atrial natriuretic peptide

A)is secreted by the heart when atrial pressure is high
B)results in an increased glomerular filtration rate
C)inhibits aldosterone activity
D)promotes renal excretion of water
E)has all of the above characteristics

Question 75

If a substance has a plasma concentration of 150 mg/ml and a urine concentration of 1.7 mg/ml, and the urine flow rate is 1.3 ml/min, what is the clearance of this substance?

A)15 ml/min
B)196 ml/min
C)0.4 ml/min
D)Cannot be determined with these data
E)None of the above

Question 76

The distal and collecting tubules are the site of

A)the cotransport carriers for glucose and amino acid reabsorption
B)the organic ion secretory systems
C)aldosterone and vasopressin action
D)both a and c
E)both b and c

Question 77

Plasma clearance is the

A)time required to filter blood in the glomerulus
B)amount of a substance appearing in the urine in one minute
C)amount of a substance that is filtered in one minute
D)amount of a substance secreted in one minute
E)volume of plasma cleared of a substance by the kidneys in one minute

Question 78

Which of the following does not play a role in Na⁺ reabsorption?

A)renin
B)vasopressin
C)angiotensinogen
D)aldosterone
E)atrial natriuretic peptide

Question 79

Water reabsorption occurs

A)by osmosis in the proximal tubule
B)under the control of vasopressin in the distal and collecting tubules
C)by osmosis in the distal and collecting tubules
D)under all of the above conditions
E)only under conditions b and c

Question 80

Tubular secretion of foreign substances, such as drugs, generally occurs in the

A)Bowman's capsule
B)loop of Henle
C)proximal tubule
D)collecting duct
E)glomerulus