Deck 14: A--The Urinary System

Question 1

Filtrate passes through all of these except

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

Answer 1

C

Question 2

Vasa recta are associated with

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

Answer 2

D

Question 3

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

Answer 3

C

Question 4

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

Question 5

The functional unit of the kidney is the

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

Question 6

Changes in the glomerular filtration rates are accomplished through

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

Question 7

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 these
E) normally about 20 to 25 percent of the total cardiac output, and all filtered through the glomeruli

Question 8

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 9

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 10

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.

Question 11

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 12

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 13

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) all of these
E) none of these

Question 14

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

Question 15

Identify the correct statement(s).

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

Question 16

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 17

The glomerular filtration rate

A) averages 125 ml/min
B) averages 75 liters/day
C) represents 60 to 65 percent of the cardiac output
D) is less than the rate of renal reabsorption
E) all of these

Question 18

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 19

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

A) They contribute significantly to long-term regulation of arterial blood pressure by maintaining the proper plasma volume.
B) They act directly on the interstitial fluid, the fluid that bathes the cells, 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 20

Below is a listing of nephron components and associated structures. $\begin{array}{ll}1.&\text {descending limb of loop of Henle }\\2.&\text {bowman's capsule }\\3.&\text {collecting tubule }\\4.&\text { ascending limb of loop of Henle}\\5.&\text { distal tubule }\\6.&\text {proximal tubule }\\\end{array}$
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 21

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) occurs by either active or passive transport and involves the process of transepithelial transport
E) none of these

Question 22

Tubular reabsorption

A) involves the movement of substances from the peritubular capillaries into the tubular fluid
B) involves the movement of substances from the tubular fluid into the peritubular capillaries
C) is considered to be active if any one of the five steps of transepithelial transport is active
D) involves the movement of substances from the peritubular capillaries into the tubular fluid and is considered to be active if any one of the five steps of transepithelial transport is active
E) involves the movement of substances from the tubular fluid into the peritubular capillaries and is considered to be active if any one of the five steps of transepithelial transport is active

Question 23

Tubular reabsorption involves

A) active transport
B) cotransport
C) facilitated diffusion
D) countertransport
E) all of these

Question 24

The proximal tubule

A) reabsorbs about 65 percent of the filtered water
B) is not the site of action of renin
C) is the location where glucose is reabsorbed
D) reabsorbs about 65 percent of the filtered water and is the location where glucose is reabsorbed
E) all of these

Question 25

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 26

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 27

Which is reabsorbed by the proximal convoluted tubule?

A) sodium
B) amino acids
C) glucose
D) all of these
E) none of these

Question 28

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) consists of specialized tubular cells in the juxtaglomerular apparatus and secretes renin
E) consists of specialized arteriolar smooth-muscle cells in the juxtaglomerular apparatus and secretes renin

Question 29

Into which structure does most reabsorption occur?

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

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) all of these

Question 31

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) all of these

Question 32

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) occurs in the loop of Henle, and 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 and
E) none of these

Question 33

Glucose is not normally found in the urine because

A) It does not get filtered out of glomerulus.
B) It is not found in the blood.
C) It is usually reabsorbed by renal tubule cells.
D) It is kept in the blood.
E) None of these.

Question 34

The Na⁺-K⁺ ATPase transport system that plays a pivotal role in much of 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 35

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 these

Question 36

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) blood colloid osmotic pressure and Bowman's capsule hydrostatic pressure
E) Bowman's capsule hydrostatic pressure and glomerular-capillary blood pressure

Question 37

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 tubulo-glomerular 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) a myogenic mechanism in which the afferent arteriole automatically constricts when it is stretched, and a tubulo-glomerular feedback mechanism in which vasoactive chemicals released from the juxtaglomerular apparatus bring about afferent arteriolar vasoconstriction
E) none of these

Question 38

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) results in vasodilation of the afferent arteriole and results in vasoconstriction of the afferent arteriole
E) results in vasodilation of the afferent arteriole and increases GFR

Question 39

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) afferent arteriolar vasoconstriction and reduction in GFR
E) all of these

Question 40

Which of the following is not a step in transepithelial transport?

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

Question 41

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 42

Select the major waste product of nitrogen metabolism.

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

Question 43

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 facultative reabsorption.

Question 44

When blood volume becomes abnormally low

A) Sodium reabsorption is diminished.
B) Dilute urine is formed.
C) Renin catalyzes the conversion of angiotensinogen.
D) Aldosterone is secreted by the kidney.
E) All of these.

Question 45

Given the following data for substance X (GFR = 125 ml/min, T_m = 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 46

The juxtaglomerular apparatus

A) is a combination of specialized tubular and vascular cells at a point where the beginning of the distal tubule comes into intimate contact with the afferent and efferent arterioles of the same nephron
B) secretes aldosterone
C) secretes renin
D) is a combination of specialized tubular and vascular cells at a point where the beginning of the distal tubule comes into intimate contact with the afferent and efferent arterioles of the same nephron and secretes aldosterone
E) is a combination of specialized tubular and vascular cells at a point where the beginning of the distal tubule comes into intimate contact with the afferent and efferent arterioles of the same nephron and secretes renin

Question 47

Reabsorption of chloride is

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

Question 48

Aldosterone

A) stimulates Na⁺ reabsorption in the distal and collecting tubules
B) is secreted by the JG apparatus
C) stimulates K⁺ secretion in the distal tubule
D) stimulates Na⁺ reabsorption in the distal and collecting tubules and is secreted by the JG apparatus
E) stimulates Na⁺ reabsorption in the distal and collecting tubules and stimulates K⁺ secretion in the distal tubule

Question 49

Aldosterone secretion

A) occurs in the kidney
B) is stimulated by angiotensin II
C) is controlled by the concentration of Cl^-
D) all of these
E) none of these

Question 50

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 T_m for glucose
E) produce aldosterone-induced protein, which increases the permeability of the proximal tubular cells to glucose

Question 51

Tubular maximum (T_m)

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 the maximum amount of a substance that the tubular cells can actively transport within a given time period, and occurs when the membrane carrier becomes saturated
E) is the maximum rate at which a substance is filtered at the glomerulus, and occurs when the membrane carrier becomes saturated

Question 52

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 53

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 54

T_m 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 55

Na⁺ reabsorption

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

Question 56

The juxtaglomerular apparatus

A) secretes renin in response to sodium depletion or plasma volume reduction
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) is where reabsorption of sodium occurs
D) secretes renin in response to sodium depletion or plasma volume reduction, and 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
E) all of these

Question 57

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 58

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 T_m 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 59

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) acts on the adrenal cortex to stimulate aldosterone secretion
D) is formed as a result of activation of angiotensinogen by renin, and is transformed into angiotensin II as a result of converting enzyme action in the lungs
E) all of these

Question 60

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

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

Question 61

Water reabsorption

A) occurs passively by osmosis in the proximal tubule
B) is under the control of vasopressin in the distal and collecting tubules
C) occurs by active transport in the distal and collecting tubules
D) all of these
E) occurs passively by osmosis in the proximal tubule and is under the control of vasopressin in the distal and collecting tubules

Question 62

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 these

Question 63

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

Question 64

Which substance is normally secreted into the tubule?

A) hydrogen ions
B) potassium ions
C) organic ions
D) hydrogen ions and potassium ions
E) all of these

Question 65

Which of the following has a positive effect on aldosterone secretion?

A) an increase in plasma K⁺
B) a decrease in plasma K⁺
C) activation of the renin-angiotensin pathway
D) an increase in plasma K⁺ and activation of the renin-angiotensin pathway
E) a decrease in plasma K⁺ and activation of the renin-angiotensin pathway

Question 66

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 67

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 of time
C) amount of a substance that is filtered in one minute of time
D) amount of a substance secreted in one minute of time
E) volume of plasma that is completely cleared of a substance by the kidneys in one minute of time

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 the waste product with the smallest molecular size in the glomerular filtrate and is in greater concentration at the end of the proximal tubule than in other body fluids
E) all of these

Question 69

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 70

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 anions and cations occurs in the proximal tubule by two distinct types of carriers
E) all of these

Question 71

Urea

A) is a waste product resulting from the breakdown of protein
B) is 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) recycling between the late portion of the collecting tubule and the long loops of Henle contributes to medullary hypertonicity
D) is found in the blood, filtrate, and urine
E) all of these

Question 72

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 73

Potassium

A) is actively reabsorbed in the proximal tubule
B) is actively secreted in the distal and collecting tubules
C) secretion is controlled by aldosterone
D) is filtered, reabsorbed, and secreted in the kidney
E) all of these

Question 74

Tubular secretion is important

A) in the renal regulation of hydrogen ion concentration
B) for the elimination of metabolic waste products from the body
C) in the renal regulation of sodium balance
D) in the secretion of renin
E) all of these

Question 75

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) all of these

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) the cotransport carriers for glucose and amino acid reabsorption, and aldosterone and vasopressin action
E) the organic ion secretory systems and aldosterone and vasopressin action

Question 77

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 78

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 79

Water reabsorption

A) cannot occur from any portion of the nephron in the absence of vasopressin
B) occurs to the greatest extent in the proximal convoluted tubule
C) is under vasopressin control in the proximal tubule
D) is under vasopressin control in the distal and collecting tubules
E) occurs to the greatest extent in the proximal convoluted tubule and is under vasopressin control in the distal and collecting tubules

Question 80

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) involves transepithelial transport and is the movement of a substance from the peritubular capillary blood into the tubular fluid
E) is the movement of a substance from the peritubular capillary blood into the tubular fluid and always occurs by active transport