Deck 13: The Urinary System

Question 1

Filtration slits:

A) provide a pathway through which fluid from the glomerulus can enter the Bowman's capsule..
B) allow proteins to pass into the filtrate
C) are not found in all nephrons
D) do not allow nutrients to pass into the filtrate
E) are important in the ability of the kidneys to produce urine of varying concentration.

Answer 1

provide a pathway through which fluid from the glomerulus can enter the Bowman's capsule..

Question 2

Filtrate passes through all of these except

A) glomerular capillary pores.
B) basement membrane.
C) podocytes.
D) filtration slits.
E) none of these answers.

Answer 2

podocytes.

Question 3

Vasa recta are associated with

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

Answer 3

juxtamedullary nephron.

Question 4

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 answers.

Question 5

This vessel carries blood directly into the capillary beds of each nephron:

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

Question 6

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 answers.
E) none of these answers.

Question 7

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

A) excretion of metabolic wastes.
B) maintaining proper plasma volume.
C) secreting aldosterone to regulate sodium.
D) maintains proper osmolarity of body fluids.
E) assisting in maintaining the proper acid-base balance of the body.

Question 8

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 9

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 10

Which of the following is not found in the filtrate at the beginning of the proximal tubules

A) water
B) glucose
C) urea
D) salts
E) all of the above are found

Question 11

Which of the following statements concerning the process of glomerular filtration is correct?

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) two of these answers.
E) all of these answers.

Question 12

The functional unit of the kidney is the

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

Question 13

Which of the following is not found in the filtrate at the end of the proximal tubules

A) water
B) glucose
C) urea
D) salts
E) all of the above are found

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

The glomerular filtration rate

A) averages 125 ml/min.
B) varies significantly as blood pressure changes
C) represents 60 to 65% of the cardiac output.
D) can be measured by calculating inulin clearance
E) any two of the above

Question 16

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 17

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) both (a) and (b) above.
E) all of these answers.

Question 18

The blood that flows through the kidneys is

A) normally about 20 to 25% of the total cardiac output.
B) all filtered through the glomeruli.
C) all used to supply the renal tissue with O₂ and nutrients.
D) both (a) and (b) above.
E) all of these answers.

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 several hormones.

Question 20

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 21

Glucose and amino acids are transferred by means of:

A) osmosis
B) primary active transport
C) secondary active transport
D) simple diffusion
E) facilitated diffusion

Question 22

Tubular maximum (Tm_max)

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) both (a) and (c) above.
E) both (b) and (c) above.

Question 23

Which of the following statements regarding tubular reabsorption is incorrect? Tubular reabsorption

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

Question 24

Glucose is not normally found in the urine because:

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

Question 25

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) two of these answers.
E) all of these answers.

Question 26

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) both (a) and (b) above.
E) none of these answers.

Question 27

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) both (b) and (c) above.
E) all of these answers.

Question 28

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) above.
E) both (b) and (c) above.

Question 29

Which is reabsorbed under hormonal control by the proximal tubule?

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

Question 30

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 31

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 32

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 33

The proximal tubule

A) reabsorbs about 65% of the filtered water.
B) is the site of action for vasopressin
C) is the location where glucose is secreted
D) lies between the loop of Henle and the collecting ducts
E) none of these answers.

Question 34

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) can override autoregulatory mechanisms
E) all of these answers.

Question 35

The GLUT transporter is:

A) moves salt
B) moves water
C) is found in the distal tubules
D) located on the basolateral membrane of tubule cells
E) is an active transporter

Question 36

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) both (a) and (c) above.
E) both (b) and (c) above.

Question 37

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 answers.

Question 38

Which structure is the primary target for aldosterone?

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

Question 39

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 40

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) both (a) and (c) above.
E) both (b) and (c) above.

Question 41

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

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

Question 42

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) both (a) and (b) above.
E) all of these answers.

Question 43

When blood volume becomes abnormally low all of the following occur except:

A) sodium reabsorption is increased
B) concentrated urine is formed
C) renin release is increased
D) aldosterone is secreted by the kidney.
E) vasopressin levels rise

Question 44

Select the major waste product of nitrogen metabolism.

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

Question 45

Aldosterone secretion

A) is controlled by the concentration of K⁺
B) is stimulated by angiotensin II.
C) is controlled by the concentration of Cl^-.
D) both (a) and (b)
E) both (b) and (c)

Question 46

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 is reabsorbed on a daily basis.
E) aldosterone is a key hormone involved in facultative reabsorption.

Question 47

The normal glucose concentration in the plasma is about____ mg per 100 ml.

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

Question 48

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) both (a) and (b) above.
E) both (a) and (c) above.

Question 49

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 50

During reabsorption, for the most part chloride ions:

A) pass between cells
B) move down their electrical gradient
C) move against their concentration gradient
D) both (a) and (b)
E) all of the above

Question 51

Which transporter is a symport carrier for glucose?

A) SGLT
B) Na⁺-K⁺ ATPase
C) GLUT
D) both (a) and (c)
E) none of the above

Question 52

The glucose concentration in the plasma when glucose first starts to appear in the urine is about____ mg per 100 ml.

A) 30
B) 60
C) 100
D) 150
E) none of the above

Question 53

Reabsorption of chloride

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

Question 54

Which of the following is true of potassium ions?

A) they are actively secreted in the proximal tubule
B) their concentration is controlled by aldosterone
C) changes in concentration can affect membrane excitability
D) are reabsorbed in the distal tubule
E) both (b) and (c)

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) both (a) and (b) above.
E) all of these answers.

Question 56

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) both (a) and (b) above.
E) all of these answers.

Question 57

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

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

Question 58

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

Question 59

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

A) atrial natriuretic peptide.
B) vasopressin.
C) angiotensin II.
D) aldosterone.
E) none of the above

Question 60

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) both (a) and (b) above.
E) both (a) and (c) above.

Question 61

Which of the following statements concerning water reabsorption 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 62

Which of the following stimulates 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) above.
E) both (b) and (c) above.

Question 63

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 answers.

Question 64

Secretion of organic ions:

A) occurs only for anions, not cations
B) is a highly selective process
C) occurs across all parts of the tubule
D) is regulated by hormones
E) involves the removal of many foreign organic chemicals, including food additives, environmental pollutants, drugs

Question 65

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) both (a) and (b) above are correct.
E) all of these answers.

Question 66

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) both (b) and (d) above.

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

Which substance is normally secreted into the tubule

A) hydrogen ions.
B) potassium ions.
C) organic ions
D) both (a) and (b) above.
E) all of these answers.

Question 69

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 70

Urea

A) reabsorption occurs passively in the distal tubules
B) is only 50% reabsorbed in the proximal tubule.
C) is not normally found in the urine because it is completely reabsorbed
D) reabsorption is controlled by aldosterone
E) has a clearance value of 0

Question 71

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) both (a) and (b) above.
E) all of these answers.

Question 72

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 73

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) both (a) and (b) above.
E) all of these answers.

Question 74

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) both (a) and (b) above.
E) all of these answers.

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) can not be determined with these data.
E) none of these answers.

Question 76

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) both (a) and (b) above.
E) both (b) and (c) above.

Question 77

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) both (a) and (b) above.
E) all of these answers.

Question 78

Drinking a large amount of water over a short period of time would cause an increase in which of the following?

A) renin.
B) vasopressin.
C) angiotensin II
D) aldosterone.
E) none of the above

Question 79

The distal and collecting tubules are the site of

A) the co-transport carriers for glucose and amino acid reabsorption.
B) the organic ion secretory systems.
C) aldosterone and vasopressin action.
D) both (a) and (c) above.
E) both (b) and (c) above.

Question 80

Secretion of organic ions takes place in the:

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